Term
| What terms are used to describe "acutely alered consciousness" and how do you define each of these terms? |
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Definition
| lethargy (sleepy but easily aroused with stimulation); hypersomnia (excessively sleepy but normal cognition when awakened); obtundation (mental blunting, decreased alertness; shows cognitive dysfunction in addition to severe lethargy); stupor (eyes open briefly after vigorous stimulation before returning to deep sleep; cognition is impaired); coma (eyes remain closed after vigorous stimulation); delirium (altered mental state in which a disoriented, confused patient fluctuates between lethargy and agitation; mispercpeiton of sensory stimuli, hallucinations; vacillates between quiet, sleepy periods and hyper-vigilance/agitation) |
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Term
| Why is it essential to describe a patient's response to stimulation and to define what you mean by "remains obtunded" when documenting a patient's presentation? |
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Definition
| different doctors may use terms to mean slightly different things, so detailed description of patient's symptoms may be better than saying "remains obtunded" |
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Term
| What terms are used to describe patients in the aftermath of a coma and what do the terms mean? |
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Definition
| abulia (awake but apathetic, no spontaneity; may have normal cognitive function with vigorous stimulation; ex: bilateral frontal lobe disease, lobotomized); akinetic mutism (silent, alert-appearing immobility; no mental activity with vigorous sitmulation; no evidence of mental activity even with vigorous stimulation; ex: disease of frontal lobes and hypothalamus); minimally conscious state (appears "vegetative" but shows fragments of awareness); vegetative state (awake, no awareness or meaningful interaction with the environment; akinetic mutism is sometimes used interchangeably; defined as persistent if symptoms last more than 30 days) |
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Term
| When do patients in deep coma develop eye-opening? |
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Definition
| generally after 2-4 weeks, regardless of coma cause (they show sleep-wake cycles) |
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Term
| What does "vegetative" refer to in the term "vegetative state" or "persistent vegetative state" (PVS)? |
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Definition
| the "vegetative functions" of the brainstem that include maintaining sleep-wake cycles, respirations, heart rate, BP, and visceral autonomic regulation |
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Term
| If a patient is in a minimally conscious state (MCS), what might they do? |
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Definition
| reach for objects, grunt, gesture in response to a command, visually fixate and track |
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Term
| Are abulia, akinetic mutism, minimally conscious state, or vegetative state mutually exclusive terms or can they overlap? |
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Definition
| these conditions overlap and transition over time; they are NOT static; they simply describe the stimuli for arousal and the patient's response |
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Term
| What are the 2 components of consciousness? |
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Definition
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Term
| What is arousal? What brain components contribute to arousal? What do diseases of arousal cause? |
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Definition
| wakefullness/sleep-wake cycles; ascending arousal system (aka reticular activating system) of the rostral brainstem; diseases of arousal cause stupor and coma |
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Term
| What is content? What brain components contribute to content? What do diseases of content cause? |
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Definition
| all cognitive activity responsible for self-awareness and purposeful intereaction with the environment (behaviors are premeditated and not reflex); cortical circuits contribute to cognition and purposeful interaction with the world; diseases of content cause dementia |
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Term
| What is/are impossible without arousal? |
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Definition
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Term
| In the early 1900s, an encephalitis known as encephalitis lethargica caused a "sleeping sickness" with patients sleeping for 20 hours a day (described by von Economo). When autopsy/post-mortem studies were performed on those who died, where were the lesions in the brain found? Were there any variations to this presentation? |
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Definition
| rostral periaqueductal gray matter and posterior 3rd ventricle; some patients with encephalitis would sleep at most only a FEW hours per day and had lesions in the rostral hypthalamus |
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Term
| Among survivors of encephalitis lethargica, what occurred during the recovery phase? Define these terms |
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Definition
| sleep attacks and cataplexy (sudden, involuntary loss of muscle tone during emotional excitement, such as intense laughter, causing the individual to fall down)= narcolepsy, as we call it today |
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Term
| Where were the lesions found in narcoleptic patients? |
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Definition
| posterior lateral hypothalmus lying between a sleep promoting area in rostral hypothalmus and wakefulness-promoting area in upper midbrain |
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Term
| What disappears during atonic phase of cataplexy? What appears? |
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Definition
| deep tendon reflexes disappear and Babinki signs transiently appear |
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Term
| What is the sleep promoting area? What happens when it is destroyed? |
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Definition
| ventrolateral preoptic nucleus; when destroyed=insomnia |
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Term
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Definition
| loss of neurons that you can histochemically stain with Ab against neuropeptide NT orexin |
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Term
| What did long term survivors of von Economo's encephalitis/encephalitis lethargica? |
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Definition
| developed a post-encephalitic Parkinsonism syndrome |
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Term
| What does the EEG distinguish? |
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Definition
| patterns of cortical electrical activity characteristic of wakefulness versus sleep |
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Term
| What does a brainstem transection at the level of the cervical medulla cause? What happens when you mechanically ventilate someone with lesion at this point? What do successive lesions marched rostral toward the midbrain produce? What does all of thiis mean? |
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Definition
| quadriplegia and respiratory arrest are caused by a cervical medulla transection; mechanically ventilating will show a desynchronized brain wave pattern on EEG (characteristic for awake state); successive lesions marched rostral produce the SAME effect until a cut at the level of posterior colliculi (quadrigeminal plate)- at which point, EEG becomes synchronized, showing high voltage slow waves typically of sleep pattern and in some coma patients; this means that lesions of the brainstem did not affect wakefulness (as defined by EEG pattern) until the lesion reached the upper pontine and midbrain level (which corresponds to von Economo's encephalitis lethargica theory of lesions in an "arousal center of the midbrain") |
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Term
| What are the primary lesions that cause coma? |
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Definition
| extensive, acute bi-hemispheric disease; lesions of the diencephalon (thalamus and hypothalamus); lesions of the midbrain peri-aqueductal gray; involvement of upper 1/3 of pontine tegmentum |
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Term
| Is the upper brainstem typically involved in coma-causing lesions? |
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Definition
| it is unusual to have an extensive global insult (such as sudden, bilateral hemispheric disease) without affecting the upper brainstem; most of the primary lesions that cause coma notably include some part of the upper brainstem but ALWAYS include the reticular gray formation (whether in thalamus, hypothalamus, midbrain peri-aqueductal gray, or upper 1/3 of pons) |
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Term
| Is damage secondary to herniation syndrome common in primary lesions leading to coma? |
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Definition
| yes (though not shown in pictures in the lecture); damage to diencephalon, micbrain peri-aqueductal gray, and upper 1/3 of pontine tegmentum is often secondary to herniation syndrome affecting one or both cerebral hemispheres |
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Term
| What is the reticular gray formation? What does it do? |
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Definition
| diffuse aggregations (found among CN nuclei and other clearly demarcated cell groups) of neurons of different types/sizes, separated by fibers traveling in all direction; sections stained to show neuronal processes displayed a net-like/reticular pattern of fibers (myelin) and cell bodies; provide heightened alertness to sudden major sensory changes (really does much more than this- cytoarchitectonic differences exist between different areas of reticular formation and various cell groups have highly specific connections) |
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Term
| If diencephalon/most of the midbrain are spared injury in your coma patient, where might you expect the injury/lesion to be? |
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Definition
| most commonly in the paramedian tegmental area just ventral to aqueduct of Sylvius from midbrain to rostral pons |
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Term
| Knowing that the paramedian tegmental area just ventral to aqueduct of Sylvius from midbrain to rostral pons is a common lesion helps to explain what? |
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Definition
| lesions confined to upper pons can cause coma in absence of midbrain and thalamic injury, explaining why some paitnets with pontine hemorrhage are comatose |
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Term
| What do lesions below the rostral pons disrupt? |
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Definition
| disrupt corticospinal and corticobulbar tracts bilaterally to leave patient quadriplegic with a paralyzed lower face, unable to speak, swallow, or breathe on his/her own BUT patient is conscious, aware, can see and hear, retains some control voer vertical eye movements and blinking through which he can communicate with outside world |
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Term
| How should you treat "locked-in" patients? |
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Definition
| patients with more caudal pontine hemorrhages appear to be in a coma but actually awake and "locked-in," and you should treat them as fully conscious and mentally competent (therfore, you must make the correct diagnosis) |
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Term
| What is the minimal amount of reticular formation that can be damaged in the upper brainstem to produce coma? |
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Definition
| paramedian tegmental area just ventral to aqueduct of Sylvius from midbrain to rostral pons |
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Term
| What is the reticular activating system? Where is it? How might it be impaired? |
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Definition
| RAS= areas of reticular formation that might result in coma when damage; RAS lies in intralaminar nuclei of thalamus, the tegmentum of midbrain, and the tegmentum of the upper 1/3 of the pons (extends from upper 1/3 of pons through midbrain tegmentum and through 3rd ventricle into thalmus); may be impaired by structural lesions, or by diffuse metabolic conditions (injuries include traumatic, hemorrhagic, ischemic, or metabolic) |
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Term
| What does the Ascending Arousal System (AAS) include? |
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Definition
| cholinergic nuclei that put that thalamus in "transmission" mode for relaying sensory info to the cortex; consists of multiple ascending pathways originating in tegmentum of midbrain and pons |
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Term
| How is the cortex activated in the AAS? |
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Definition
| acitvated directly by monoaminergic inputs to improve the signal to noise ratio and avoid misperception of incoming stimuli (like that which occurs in delirium) |
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Term
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Definition
| cholinergic lateral dorsal tegmental (LDT) and pedunculopontine tegmental (PPT) nuclei project to thalamic relay nuclei that are inhibited from firing, increasing wakefulness and placing thaalmus in transmission mode for filtering and relaying sensory info to cortex |
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Term
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Definition
| increased bursting by thalmic relay neurons promotes synchronization of cortical activity, inducing sleep |
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Term
| What is the purpose of monoaminergic systems of AAS? |
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Definition
| direct and indirect connections that are widespread to the cortex; to improve signal to noise ratio and avoid misperception of incoming sensory stimuli (delirium results if system fails) |
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Term
| What is the VPLO? What does it do? What drugs mimic it? |
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Definition
| ventrolateral preoptic nucleus is the sleep promoting center in the brain (causes insomnia when destroyed); deploys inhibitory NT GABA and inhibitory neuropeptide galanin to inhibit many nuclear centers that promote wakefulness and comprise the AAS; sedatives (ethanol, benzos) have GABAergic activity |
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Term
| From where does the AAS receive feedback? What do the pathways mediate? |
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Definition
| AAS receives feedback from thalamus, limbic system, frontal and association cortex; pathways mediate emotional memories and permit concentrated attention to one sensory modality when necessary; loss of feedback-->apathy and indifference to sensory stimul with severe damage causing abulia and akinetic mutism |
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Term
| What are the causes of coma? |
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Definition
| structural: supratentorial mass lesions, acute obstructive hydrocephalus, ifratentorial mass lesions; metabolic: reversible injury (sedative overdose), irreversible injury (hypoxia in cardiac arrest); always rule out psychogenic coma first |
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Term
| What symptoms/presentations might you see in structural causes of coma? What interventions might you do? |
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Definition
| raised ICP with headache made worse with recumbency, nausea, vomiting, transient visual obscurations, papilledema, focal deficits on exam and an abnormal CT/MRI pointing to hemispheric abscess, stroke,neoplasm, or mass in posterior fossa; may require neurosurgical intervention such as evacuating a subdural hematoma or placing a shunt for acute hydrocephalus |
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Term
| What symptoms/presentation might you see in metabolic causes of coma? What interventions might you do? |
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Definition
| non-focal exam with no lateralizing signs and patient may be managed medically in ICU (no need for surgery) |
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Term
| What might be trapped in a transtentorial (uncal) herniation of medial temporal lobe? What else does the herniation cause? |
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Definition
| oculomotor nerve is compressed first (particularly the nerve fascile mediating pupillary consctriction), even before pressure on midbrain and diencephalon produces ischemia and causes increased lethargy/stupor/coma; posterior cerebral artery may also be trapped against cerebellar tentorium, causing ipsilateral ischemia and stroke |
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Term
| How does a patient present bedside with uncal herniation? Are these signs important? |
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Definition
| pupil on herniated side is widened and slower to react to direct and indirect light (may precede ptosis and weakness of ocular movement); often precedes increased lethargy and development of ocntrolateral hemiparesis and controlateral babinksi sign; STRUCTURAL and SURGICAL emergency- loss of puil reactivity to light should signal possiblity of imminent herniation, raised ICP, and impending catastrophe |
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Term
| Uncal herniation might be caused by epidural hematoma from skull fracture. What else might cause it? What do you see grossly? |
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Definition
| large, malignant tumor such as glioblastoma multiforme; causes massive swelling of right/left hemisphere (depending on which side tumor is on) with herniation of medial temporal lobe; causes medial temporal lobe to herniate around the tentorium and compress brainstem; compression of brainstem causes small hemorrhages called Duret's hemorrhages; pressure against midbrain causes ischemic hemorrhagic necrosis; you may see indentation of tentorium into temporal lobe |
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Term
| What do you think gets caught between the herniating temporal lobe and the upper brainstem? |
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Definition
| oculomotor nerve; oculomotor nerve is quite close to the tentorium (rests on the uncus of the temporal lobe) |
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Term
| How can herniation involve both hemispheres? |
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Definition
| trauma that produces bilateral subdural hematoms or hemispheres are severely and irreversibly damaged by certain metabolic insults such as hypoxia or cerebral edema that accompanies fulminant liver failure (diffuse and symmetric pressure on the brain both medial and downward to produce central herniation |
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Term
| What is a falcine herniation? |
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Definition
| herniation that involves a mass effect pushing the brain under the falx cerebri; traps and compresses one or both anterior cerebral arteries against the falx to cause ischemic stroke in the parasagittal cortex on one or both sides |
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Term
| Is ICP diffuse or symmetric? |
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Definition
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Term
| How do you recognize central herniation at bedside? |
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Definition
| rostral to caudal deterioration (steady progressive failure of brainstem in that direction); diencephalon --> midbrain failure; begins with increasing lethargy due to early pressure on retircular gray in both thalami; pressure on hypothalmus and central sympathetic tracts originating in hypothalamus are then compromised, leading to small but still reactive pupils; later, pressure extends to midbrain and Edinger-Westphal nuclei fail (constrictive puipllary tone is lost and pupils become fixed in mid-position); decorticate or flexor posturing is followed by decrebrate or extensor posturing and is a late sign of herniation; Cheyne =-Stokes respirations (apneic spells interspersed with hyperventilation periods) provide an early warning of herniation |
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Term
| How do lesions produce mixed transtentorial and central herniation syndrome? |
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Definition
| lesions cause both diffuse and focal supratentorial pressure; monitor transtentorial by lateral signs and by neuroimaging |
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Term
| Describe infratentorial lesions. |
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Definition
| below the cerebellar tentorium in the posterior fossa; intrinsic brainstem lesions: top of the basilar artery, ischemic stroke; pontine hemorrhage OR extrinsic lesions that compress and distort the brainstem: cerebellar hemorrhage/infarction/brain tumor |
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Term
| What do primary brainstem lesions cause? |
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Definition
| segmental cranial nerve deficits; ascending (spinothalamic) tract dysfunction- contralateral pain and temprature is reduced; descending (corticospinal, central sympathetic) tract dysfunction; early cerebellar signs ; medial lemniscus carries fine touch, vibration, and propriocenptive information |
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Term
| What do pontine hemorrhages cause? |
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Definition
| a distinct clinical syndrome: abrupt coma, pinpoint pupils, decerebrate rigidity or flaccid quadriplegia, horizontal gaze paresis, ocular bobbing |
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Term
| What is metabolic encephalopathy (toxic-metabolic coma)? |
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Definition
| non-cerebral disease that may interfere with the metabolism of the cerebral cortex and rostral brainstem AAS; endogenous toxins in uremia and hepatic failure; exogenous toxins in drug overdose, poisons, and sepsis; hypoxia, hypoglycemia, hypo- and hyper-osmolality; electrolyte and acid-base imbalances |
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Term
| What causes metabolic encephalopathy? |
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Definition
| metabolic abnormalities such as: hyponatremia, hypoglycemia, hypothermia, hyperglycemia, uremia, hepatic failure, thiamine deficiency, hypoxia, drug intoxication, etc (cause altered mental status due to metabolic encephalopathy) |
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Term
| How do you recognize metabolic encephalopathy at bedside? |
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Definition
| neurological deficits are diffuse and global (b/c the metabolic insult is also diffuse and global); insult is symmetric; neuro exam is non-focal (minimal or no lateralizing signs such as hemiparesis); negative head CT (or old findings): pupils stay reactive even with other brainstem reflexes lost (exceptions: atropine, botulism, glutethimide); asterixes, multifocal myoclonus and tremor (ex: uremia, liver failure, hypoxia); stupor and coma are reversible with metabolic correction and ICU support |
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Term
| What is one significant sign difference between metabolic and structural causes of coma? |
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Definition
| In metabolic causes, the pupils are often the last to go whereas in structural causes, pupils are often the earliest to be affected |
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Term
| What is another way to describe asterixes? |
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Definition
| negative myoclonus (refers to sudden lapse in muscle tone) |
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Term
| Describe multifocal myoclonus. |
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Definition
| refers to mucle twitching in different parts of the body that occurs in chaotic and unpredictable fashion (reversible etiologies for these abnormal movements are liver failure, uremia, hypoxia, drug overdose; irreversible in the rare Creutzfeld-Jacob dx) |
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Term
| Which causes of metabolic encephalopathy are common in the elderly? |
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Definition
| dehydration; drug intoxication; sepsis; Wernicke's (thiamine deficiency) |
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Term
| How does the post-ictal state compare to metabolic encephalopathy? |
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Definition
| post-ictal state may mimic metabolic encephalopathy but consciousness improves over the next few hours |
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Term
| How can a metabolic encephalopathy and a structural lesion be confused? |
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Definition
| if a patient has an old and well-compensated brain lesion (ex: stroke), a new metabolic encephalopathy may unmask the old lesion and foold the clinician into thinking there is an acute structural lesions causing new focal weakness; use CT and MRI to date the structural lesion and get diagnosis back on track |
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Term
| What do you do for immediate management of coma? |
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Definition
| stabilize vital signs (ABCs first)- secure airway, cardiac monitor, IV access and blood draw; stabilize neck (particularly in trauma but assume neck is broken until you get a CT or x-ray to clear the C spine if you are unclear about trauma as a possiblity); determine circumstances (history); rapidly examine the patient; empirical D50 (in case patient is hypoglycemic) preceded by IV thiamine, naloxone (opiate OD); tasks performed simultaneously by ED team |
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Term
| Do coma patients have normal vital signs? |
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Definition
| seldom! Usually increased/decreased body temp or purlse or BP or respirations..abnormal patterns; if you find normal vital signs in someone who is not responding , consider psychogenic coma (test by ice water calorics) |
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Term
| In coma patients, what do you look for on the skin? |
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Definition
| petechiae, purpura, spider angiomata, jaundice, splinter hemorrhages, needle tracks; clues to meningococcal meningitis, Rocky Mtn Spotted Fever, hepatic encephalopathy, bacterial endocarditis |
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Term
| What do retinal venous pulsations do for our diagnosis? |
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Definition
| increased ICP is NOT a aprt of the equation so a huge list of diagnostic possibilities have been eliminated |
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Term
| What do you ask in your history of a comatose patient? |
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Definition
| onset of coma (sudden-->head trauma, seizure, top of basilar artery embolic stroke, masive brain hemorrhage); recent complains of HA, head injury, depression, limb weakness, dizziness; hx of psychiatric illness; medical illnesses predisposing to metabolic encephalopathy (diabetes, renal failure, alcoholism, absue of sedative or street drugs) |
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Term
| What do respiratory patterns in coma depend on? |
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Definition
| site of lesion; remember that Cheyne-Stokes respirations can be early warning sign of transtentorial or central herniation |
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Term
| What are some noxious stimuli to arouse patients who do not respond to voice command? |
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Definition
| motor response is important SO you may try: pressure on supraorbital nerve, nailbed pinch, sternal rub (painful but leave no marks); nipple pinch or twisting may leave a bruise which appears sadistic |
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Term
| What does a flexor response to pain indicate? |
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Definition
| loss of cortical control of brainstem motor centers (corticospinal tract, rubrospinal tract, tectospinal tract, rostral reticulospinal tract are all flexor facilitory- origins at cortex or midbrain level); aka decorticate posturing |
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Term
| What does extensor response to pain indicate? |
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Definition
| aka decerebrate posturing; arises with loss of red nucleus and rubrospinal tract in midbrain; vestibulospinal tract and caudal reticulospinal are extensor facilitatory (origin at pontine level) |
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Term
| What is the Glasgow coma scale? |
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Definition
| developed for prognosis in head trauma; score of 15 has excellent prognosis; 8 is poor; and 3 is very poor(usually death); measure eye opening, motor response |
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Term
| How do you measure prognosis in regards to motor response in coma patients? |
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Definition
| For prognosis: best response is following a complex motor command; slightly greater injury shows patients following simple commands; with no response t ovoice command, painful stimulus is introduced with highest level of response is localizing pain and pushing away offending hand; next decrement is purposeful withdrawal to pain, following by semi-purposeful movement to pain; next are reflex, stereotypic responses to pain (definite deterioration), first with flexor responses, then extensor; prognosisis worse with extensor posturing; changing from flexor to extensor posturing is a dire development (patient just lost midbrain); worst prognosis is no motor response at all (ex; such a severe insult, such as hypoxia and hypotension, that even spinal cord suffers direct hypoxic damage) |
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Term
| How do flexor and extensor responses interact? |
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Definition
| balance between extensor and flexor in response to pain favors flexor posturing when cerebrum loses conscious control of movement; once midbrain is compromied, flexor influence is lost and pontine extensor pathways dominate |
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Term
| Which lab tests to do you use to evaluate metabolic coma? |
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Definition
| stat tests: venous blood (glucose, electrolytes, urea or creatinine, osmolality, CBC, coag studies); arterial blood (color, pH, PO2, PCO2, carboxyhemoglobin, esp if blood is bright red); CSF (cells, gram stain, glucose); EKG; additional tests: venous blood (LFTs, thyroid and adrenal function, blood cultures, viral titers); urine (culture); CSF (protein, culture, viral and fungal Ab, PCR) |
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Term
| What diagnostic testing is used in coma? What are those tests looking for? |
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Definition
| STAT Head CT (or MRI if available; screen for structural etiologies such as trauma, ischemic stroke, hemorrhage, other mass lesions, herniations, hydrocephalus); CXR (screen for CHF, pneumonia, lung cancer); special tests: EEG (status epilepticus, brain death), spinal tap (CNS infx, SAH), cervical spine X-ray (trauma), STAT toxicology (cocaine, opiates, phencyclidine; barbiturates, anticonvulsants, sedatives; ethanol, methanol, ethylene glycol; acetaminophen, salicylates, tricyclics, others) |
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Term
|
Definition
| Apart from necessary surgical intervention: ensure oxygenation (check blood gas that it is adequate and not inducing CO2 narcsosis); maintain circulation (BP must be maintained with IV fluids and pressor agents if necessary); control glucose; lower ICP (hyperventilation can bring PCO2 down to 25-30 mm Hg to reduce pressure for 30 min or so; mannitol/other osmotic agnets can draw free water out of brain and into circulation- allows extra time to get to OR so shunt could be placed); stop seizures (anticonvulsants); treat infx (Abx empirically given if chance of CNS infx and/or sepsis); restore acid-base balance and electrolytes; body tempoerature adjusted (may help to lower temp in conditions such as ischemia or hypoxia); give thiamine and multivitamins; give antitode if specific cause is known (ex: naloxone, flumazenil); control agitation (haldol, ativan for sedation; hypoxia can be unsuspected cause of agitated delirium and treatment is with O2; sedation and tight restraints can result in respiratory arrest |
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Term
| In non-traumatic coma, what might indicate poor prognosis? |
|
Definition
| absence of pupillary light and coreneal reflex at 3 days |
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Term
| In hypoxic coma, what might indicate poor prognosis? |
|
Definition
| absence of purposeful motor movements at 3 days |
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Term
| When is there zero chance of moderate disability/good recovery on day 3? |
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Definition
| if the corneal reflex is absent and motor response is absent or reflex at best showing extensor or flexor posturing |
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Term
| What is the clinical criteria for brain death in adults and children in the US? |
|
Definition
| coma of established cause (no presence of potentially anesthetizing amounts of toxins or therapeutic drugs; no hypothermia below 30°C or other physiologic abnormalities; irreversible structural disease or a known and irreversible endogenous metabolic cause due to organ failure); absence of motor responses (absence of pupillary responses to light and pupils at midposition with respect to dilation 4-6 mm; absence of corneal/gag/sucking/rooting reflexes; absence of caloric vestibulo-ocular responses; absence of coughing in response to tracheal suctioning; absence of respirtaory drive at PaCO2 that is 60 mmHg or 20 mmHg above normal baseline values- apnea testing); interval between 2 evaluations by patients age (term to 2 months: 48 hours; >2 months to 1 year: 24 hours; >1 year to <18 years : 12 hours; ≥ 18 years, optional); confirmatory tests (term to 2 months: 2 confirmatory tests >2 months to 1 year: 1 confirmatory test >1 year to <18 years optional; ≥ 18 years, optional) |
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Term
|
Definition
| any disease that affects the spinal cord |
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|
Term
| Where does the spinal cord end? |
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Definition
|
|
Term
| Where are spinal taps performed? |
|
Definition
|
|
Term
|
Definition
| lumbar - if a patient describes thoracic back pain, be concerned |
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|
Term
| Describe pertinent spinal cord anatomy and presentations of lesions at those anatomical locations. |
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Definition
| root: lancinating pain, numbness, hyporeflexia; spinothalamic tract: loss of pain and temperature, sensory level; posterior columns: loss of vibration, position sense, Romberg sign; corticospinal tract: hyperreflexia, spasticity, Babinski signs, weakness; Anterior horn cells: flaccid weaness, hyporeflexia, fasciculations |
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Term
| Describe spinal cord anatomy from inside of cord to outside. Which areas have multiple terms for description? |
|
Definition
| spinal cord (parenchyma)-->pia mater-->subarachnoid space-->subdural space-->dura-->epidrual space (with fat)-->bone (vertebral body) remember that epidural=extradural; intradural=subdural; leptomeningeal=within the subarachnoid space; intramedullary=within spinal cord parenchyma |
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|
Term
| What is notable in an MRI of the cervical spine? |
|
Definition
| CSF is white; spinal cord is gray/black; proximity of cord to discs, vertebral bodies, etc |
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|
Term
| What are common sensory dermatomes in spinal cord lesions? |
|
Definition
| patients with spinal cord syndrome commonly develop sensory levels (they cannot feel sensation at or below this level); T4 is the nipple line; T10 is the umbilicus |
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Term
| What is common in spinal cord lesions? What is the mechanism? |
|
Definition
| sphincter dysfunction is common; micturition (bladder control) is a CNS phenomenon (complex process controlled by brain and spinal cord), so bladder symptoms are common in spinal cord lesions; long axons from frontal lobe of brain synapse in thoracic and sacral areas of spinal cord, making these tracts very vulnerable to injury |
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Term
| What bladder symptoms might you expect in spinal cord lesions? |
|
Definition
| 2 kinds- acute and chronic; acute= urinary retention with some overflow incontinence while chronic= small spastic bladder that does not completely empty with spasms, urinary frequency, urge incontinence |
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Term
| How do you approach a patient with acute/subacutemyelopathy? |
|
Definition
| acute and subacute myelopathies are neurologic emergencies! Recognize signs and symptoms; IMMEDIATE neuro-radiologic testing; other diagnostic tests depending on clinical picture; LP may be needed (especially with negative neuro-radiologic testing); therapy is usually IV steroids |
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|
Term
| How do you approach a patient with chronic myelopathies? |
|
Definition
| you need to RECOGNIZE them as many are reversible; work up on an expedited basis; recognize signs and symptoms; neuro-radiologic testing to rule out compressive myelopathies; other diagnostic tests depending on clinical picture; LP (esp if neuro-radiologic testing is negative); therapy directly related to cause of myelopathy |
|
|
Term
| How does therapy differ in chronic versus acute/subacute myelopathy? |
|
Definition
| chronic: treat the cause; acute/subacute: IV steroids |
|
|
Term
| Generally speaking, what do you ask about in history for a patient in which you suspect myelopathy? General exam? Neuro exam? |
|
Definition
| Hx: other illnesses, fever, location of pain, neuro symptoms, pace of symptoms; General exam: fever, have patient show you where it hurts, check for vertebral body tenderness; Neuro exam: motor weakness and tone; sensory pain or temperature, joint position sense/vibration; reflexes (Babinski), gait |
|
|
Term
| Why is the pace of symptoms critical when dealing with myelopathy? |
|
Definition
| pace is critical and unpredictable b/c patients may walk into your office and without recognition of symptoms, they may be paralyzed when they leave |
|
|
Term
| Describe the progression of an epidural lesion. |
|
Definition
| A. may occur over hours to days; motor symptoms are usually early (compression of corticospinal tract) with hyperreflexia, Babinski signs, difficulty walking (weakness is not always evident); sensory: numbness or allodynia if dorsal root is damaged or compressed at level of lesion (root irritatio)n, hypersesnitive to touch (IPSILATERAL), if spinothalamic tract is injured at this point, subtle changes in sensory symptoms seen in CONTRALATERAL lower extremity; band or girdle-like sensation in the abdomen; urinary urgency (DO NOT FORGET TO ASK- patients may be embarassed); B. may occur over hours to days; motor: spastic and weak legs, brisk reflexes, Babinski; sensory: symptoms are worse with root area is totally numb (ipsilateral), pain in contralateral LE is decreased (spinothalamic); definite sphincter dysfunction ; may appear as Partial Brown-Sequard Syndrome: hemi-cord syndrome with weakness and numbness to touch and vibration on the IPSILATERAL side AND loss of pain sensation on the CONTRALATERAL side due to crossing of spinothalamic tract within the spinal cord; C. may occur over hours to days; final stage- may be acute; motor:if acute or hyper-acute, flaccid, areflexic due to spinal cord shock OR spastic paraparesis if more chronic or subacute or slow; sensory: complete sensory level to all modalities at level of the lesion |
|
|
Term
| What are some extradural examples of myelopathy? Intradural extramedullary? Intramedullary? (these were starred in the notes) |
|
Definition
| Disc disease, metastatic tumor, abscess/// neurinoma, meningioma///syringomyelia, glioma,myelitis |
|
|
Term
| Describe myelopathy caused by disc disease. |
|
Definition
| severe disc disease in cervical or thoracic cord can cause epidural cord compression and myelopathy; herniated disc or degnerative disc disease; may see edema associated with compression; treat with steroids and surgery |
|
|
Term
| Describe spinal cord trauma. |
|
Definition
| paraparesis/paraplegia; quadriparesis/quadriplegia; vertebral body compression; hematoma; spinal cord infarct; cord transection; patient may present with spinal cord "shock" b/c of acuity of lesion; treat with methylprednisolone 30 mg/kg IV over 1 hour and follow with 5.4 mg/kg/hr over the next 23 hours |
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|
Term
| What are some causes of spinal cord dysfunction in patients with cancer? |
|
Definition
| cancers can affect spinal cord at every level/layer; epidural cord compression due to tumor, abscess, hematoma; intramedullary processes due to metastases, abscess, hematoma, syrinx; other myelopathies due to radiation, chemotherapy, paraneoplastic; neoplastic meningitis; spinal arachnoiditis |
|
|
Term
| Where is epidural compression common? |
|
Definition
| complication of metastatic cancer; cancer enters vertebral body, weakens it, expands, and then compresses spinal cord; most common in lung, breast, prostate cancer |
|
|
Term
| What do you do if you suspect spinal cord compression? |
|
Definition
| treat with steroids (dexamethasone), spinal MRI with gadolinium, and follow patient slowly; neurosurgical consult; CT myelograms are rare (sensitivity and non-invasiveness of MRI); even with negative work-up, cancer cells may enter SA space, cause meningitis and spinal cord injury so a spinal tap is REQUIRED if no evidence of cord compression by imaging techniques |
|
|
Term
| Where do most metastic cancers begin (in the spine)? |
|
Definition
|
|
Term
| Where do most spinal abscesses begin? What causes them? How do you test it? |
|
Definition
| spinal abscesses usually begin in disc space and expand to cause spinal cord compression; most common infection involved is Staph aureus; be suspiciuos in IV drug users; use MRI of spine to test |
|
|
Term
| What are the signs and symptoms of epidural abscess? What are the risk factors? |
|
Definition
| fever, pain on percussion, elevated white count, elevated ESR; risk factors include IV drug use, HIV, immunosuppression |
|
|
Term
|
Definition
| infection of the vertebral bodies, causing weakness of bones, collapse of vertebral body, and subsequent cord compression |
|
|
Term
|
Definition
| classic neurologic syndrome of osteomyelitis from TB infection |
|
|
Term
| What is a spinal meningioma? |
|
Definition
| usually typical benign meningiomas; 2nd most common of spinal tumor; classic patient is middle-aged women; most common in thoracic spine; 90% are intradural extramedullary; image findings: bone erosion, Ca rare, isointense with cord on T1- and T2WI, moderate contrast enhancement, +/- dural "tail"; clinical clue: occasionally, benign herniated disc occur in thoracic spine but most diseases of thoracic spine are bad |
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|
Term
| Describe nerve sheath tumors. |
|
Definition
| variable location but most common intradural extramedullary mass; Schwannoma and neurofibroma are most common types; usually seen in middle-aged adults; dumbell shape is relatively uncommon but CLASSIC; clinical symptoms mimic disc herniation; image findings: enlarged neural foramen is common, Ca rare; 75% isointense and 25% hyperintense on T1WI; >95% hyperintense on T2WI; virtually 100% enhance |
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Term
| Describe the progression of a central cord lesion (lesions beginning in the spinal cord parenchyma itself). |
|
Definition
| A: may start in central spinal cord, where spinothalamic fibers cross, so loss of pain and temperature is an early sign; also begins with pain in shoulders (cervical lesion); B. as lesion involves dorsal root entry zones, reflexes are lost in arms; continued loss of pain and temperature (more severe); Horner's syndrome due to involvement of sympathetic pathways; posterior columns are spared until late so touch and joint position are intact though pain and temperature are lost (konwn as dissociated sensory level); below lesion, involvement of corticospinal pathways result in spastic paraparesis, hyperreflexia, and Babinski signs;C. worsening of symptoms but there may be sacral sparing b/c those fibers are the most lateral from central cord/spinothalamics (not damaged and sacral dermatomes maintain normal sensation); may involve face due to sensory nucleus of trigeminal nerve |
|
|
Term
| What is the classic central cord syndrome? |
|
Definition
| syrinx- large expanding space in spinal cord; can be result of a trauma or tumor |
|
|
Term
| Describe spinal cord astrocytoma. |
|
Definition
| central cord syndrome; usually low grade fibrillary astrocytoma, anaplastic astrocytoma, GBM rare; 2nd most common spinal cord tumor overal (most common cord tumor in children); cause of low back pain and painful scoliosis in children; image findings: long, multisegment intramedullary mass typical, causes diffuse cord expansion; interpediculate distance widened and pedicles thinned; iso-to-hypointense on T1; hyperintense on T2WI; cysts common, often extensive; virtually 100% enhance; large amount of edema |
|
|
Term
| Describe vascular disease of the spinal cord. |
|
Definition
| aneurysm, AVM, infarct much less common than in brain; aneurysm EXTREMELY rare except with AVM; infarct secondary to atherosclerosis, aortic dissection, disck herniation, trauma, hypertension, etc; venous infarct (?Foix-Alajouanin syndrome); Spinal cord vascular supply: one anterior, 2 posterior spinal arteries; anterior spinal artery (Adamkiewicz) supplies 70% of cord; many end arteries, comparative few collaterals; watershed zone at periphery of central gray matter |
|
|
Term
| Describe anterior spinal artery syndrome. (what does it affect/symptoms/etc) |
|
Definition
| aka artery of Adamkiewicz or great radicular artery; anterior 2/3 of spinal cord is supplied by this artery (located in mid-thoracic region); sypmtoms referable to spinothalamic (pain/temp/sensory level loss), corticospinal function (weakness) but INTACT POSTERIOR COLUMN FUNCTION (vibration and joint position) |
|
|
Term
| Describe anterior spinal artery syndrome caused by AVM. |
|
Definition
| can also cause anterior spinal artery syndrome but may be incomplete due to location and area of hemorrhage |
|
|
Term
| Patient presents w/ acute onset of numbness below waste, patchy areas of numbness at torso and upper abdomen. Initially not weak but over 24 hours developed lower extremity weakness and urinary retention. What is important to note here? |
|
Definition
| patient is presenting with acute non-compressive myelopathy; note that did NOT have back pain; early urinary retention suggests a spinal cord lesion |
|
|
Term
| What do you find on neuro exam in acute non-compressive myelopathy? |
|
Definition
| HIF normal; CN full and symmetric; decreased pinprick of midchest distally; paraparesis L>R; great difficulty walking; hyperreflexic w/extensor plantar response; decreased rectal tone; post-void residual of 250 cc |
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|
Term
| What is the definition of transverse myelitis? |
|
Definition
| acute neurologic condition that reflects focal inflammation of spinal cord; acute or subacutely developing motor, sensory, and sphincter disturbance; spinal segmental level of sensory disturbance w/ well-defined upper limit; no evidence of spinal cord compression (radiological, not clinical issue); absence of other known neurologic disease; may be first sign of MS (30%) |
|
|
Term
| How do you treat transverse myelitis? |
|
Definition
|
|
Term
| What might be an early sign of multiple sclerosis? |
|
Definition
|
|
Term
| How does transverse myelitis look on MRI? |
|
Definition
| hyperintense on T2WI, acutely enhances with gadolinium |
|
|
Term
| What if you have a patient with both optic neuritis (ON) and transverse myelitis â„¢? |
|
Definition
| the patient has neuromyelitis optica (NMO) |
|
|
Term
| What does the brain MRI look like in a neuromyelitis optica patient? |
|
Definition
|
|
Term
| other than MRI, what testing might you do for neuromyelitis optica? |
|
Definition
| antibody testing for NMO titer (aquaporin 4); CSF-acute w/neutrophils but oligoclonal bands usually NEGATIVE |
|
|
Term
| How many levels of thes pinal cord are usually involved in neuromyelitis optica? |
|
Definition
| 3 or more levels usually involved |
|
|
Term
| Flaccidity is usually an indication of peripheral nerve lesion, but in the setting of complete sensory level and urinary retention, how would you view the symptom of flaccidity? |
|
Definition
| dagnosis of acute spinal cord injury |
|
|
Term
| With complete transection of the spinal cord, what symptoms do you see? What might cause it? How might you describe it? |
|
Definition
| transverse myelitis, among other causes, can lead to complete transection of the cord, which is acutely described as spinal cord shock; symptoms include flaccid paralysis, complete sensory level to all modalities, loss of bladder/bowel/sexual function, autonomic malfunction; if transection presents chronically, there is no shock and spastic paralysis accompanies the symptoms above |
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|
Term
| What causes Brown-Seuard hemi-section syndrome? |
|
Definition
| rare condition (though more common to see Brown-Sequared in partial form); sometimes seen in myelitis |
|
|
Term
| What presentation do you see in Brown-Sequard syndrome? |
|
Definition
| ipsilateral spastic paralysis (after spinal shock) below the level of the lesion; hyperreflexia; Babinski signs; ipsilateral loss of vibration and joint position sense; contralateral loss of pain and temperature |
|
|
Term
| How does B12 deficiency (pernicious anemia) cause in the spinal cord? |
|
Definition
| subacute combined degeneration of the spinal cord |
|
|
Term
| How does B12 deficiency-caused subacute combine degeneration of the spinal cord present? |
|
Definition
| spastic weakness of lower extremities; decreased sensation to vibration and position; Romberg's sign; ataxia (non-cerebellar); Babinski signs and hyperreflexia; may also cause peripheral neuropathy (mixed signs) |
|
|
Term
| How do you treat B12 deficiency? |
|
Definition
| intramuscular B12 injections |
|
|
Term
|
Definition
| human T-lymphocyte virus type 1; first human retrovirus discovered with reservoir of CD4+ T-lymphocytes |
|
|
Term
| What is HTLV-1 associated with? |
|
Definition
| HAM/TSP, acute T cell leukemia (ATL); uveitis, polymyositis; arthritis, ALS, other diseases |
|
|
Term
| What does infection with HTLV-1 cause? |
|
Definition
| spastic paraparesis and spinal cord disease |
|
|
Term
| What is HAM/TSP? What are the symptoms/clinical presentation? |
|
Definition
| HTLV-1 associated myelopathy/tropical spastic paraparesis; patients infected with HTLV-1; develop paraparesis; CNS infiltrated by monocytes; CNS demyelination and axonal degeneration (corticospinal tract > posterior columns); CSF shows oligoclonal bands and increased IgG |
|
|
Term
| What is vacuolar myelopathy? |
|
Definition
| neurologic complication of HIV infection, usually late with AIDS; progressive spastic parapresis- hyperreflexia, extensor plantar responses; sensory ataxia and incontinence; vacuolation and myelin pallor (posterior and lateral columns); resembles B12 defiency |
|
|
Term
| What resembles B12 defiency? |
|
Definition
|
|
Term
| Describe posterior tract syndrome. |
|
Definition
| loss of sensation for position and vibration; astereognosis; Romberg's sign; Tabes dorsalis (syphilis); subacute combined degeneration; Friedrich's ataxia; trauma; extramedullary tumors |
|
|
Term
|
Definition
| complication of neurosyphilis; posterior column dysfunction; loss of vibration and position sense; Romberg's sign |
|
|
Term
|
Definition
| Lou Gehrig's disease; combination of flaccid (anterior horn cell) and spastic (pyramidal tract) weakness; combination of hyper and hyporeflexia, Babinski signs; no sensory signs (included in spinal cord syndrome lecture b/c it can present clincally with spinal cord lesions) |
|
|
Term
| Remember these top 10 things about myelopathy. |
|
Definition
| acute myelopathies are neuro emergencies; spinal cord ends at L1/L2; back pain in cancer patient is an emergency until proven otherwise; myelopathies can progress quickly; do not delay neuroradiologic testing; ask the patient where it hurts; percuss the vertebral column; steroids are always always indicated in acute myelopathies (plus other tx needed); make the patient walk; remember the basic neuroanatomy |
|
|
Term
| Remember 10 things commonly on the boards. |
|
Definition
| basic spinal cord anatomy; epidural abscess; Pott's disease; Brown-Sequard syndrome; anterior spinal artery syndrome; extradural vs intradural vs intramedullary; tabes dorsalis and syphilis; dissociated sensory level; spinal cord shock; central cord vs epidural syndrome |
|
|
Term
| What is multiple sclerosis (MS)? |
|
Definition
| most common demyelinating disease in humans; chronic , inflammatory disease of CNS |
|
|
Term
| What causes MS and what results from it? |
|
Definition
| occurs when myelin (made by oligodendrocytes) is destroyed and underlying axons and neurons are damaged; pathological lesion (loss of myeling in multple areas) in the CNS is the MS plaque (inflammation and sclerosis=scar tissue); results in periodic loss of neurological function and often progressive disability |
|
|
Term
|
Definition
| periodic loss of neurologic function; a new neurologic disability that lasts greater than 24 hours |
|
|
Term
| What is Uhthoff's phenomena? Why does it occur? |
|
Definition
| MS symptoms that worsen in the heat/during increase in body temperature- very common in MS patients; occurs as a result of poor electrical conduction along demyelinated axons |
|
|
Term
| With MS relapse, do patients return to normal? |
|
Definition
| relapses may resolve over time or patients may not return entirely to normal |
|
|
Term
| Are relapses occurences of the same neurlogical symptoms or different? |
|
Definition
| relapses are separated by time and space (2 different areas of the CNS); onset is subacute (separating it from stroke); may be a recurrence of an old symptom (ex: loss of vision in same eye twice, separated by a year); may be a new symptom (ex: weakness and numbness of both legs) |
|
|
Term
| How do you visualize MS plaques? |
|
Definition
| you can visualize them with MRI- this is how you diagnose MS |
|
|
Term
| What do you seen in spinal fluid in MS patients? |
|
Definition
| inflammatory profile (lecture patient had 20 lymphocytes, elevated IgG index and oligoclonal bands; CSF protein may be normal, however; NEVER see neutrophils) |
|
|
Term
| How do MS plaques present in MRI? |
|
Definition
| bright white hyperintense areas; enhance w/gadolinium, a sign of inflammation and breakdown of BBB; periventricular |
|
|
Term
| If MS plaques enhance with gadolinium, what can you assume? |
|
Definition
| that there is an acute (new) plaque with active inflammation and breakdown of the BBB that allows gadolinium to enter the brain parenchyma |
|
|
Term
| What are the classic diagnostic criteria for MS? |
|
Definition
| clinical evidence of lesions reflecting white matter dysfunction disseminated in time and space and in expected age range (18-50); objective abnormalities on neurlogical examination (preferably at time of diagnosis); dissemination of lesions in one of 2 patterns: at least 2 clear cut episodes of functionally significant symptoms lasting over 24 hours each and separated by at least 1 month OR slow progressive deterioration of same disseminated pattern evolving over at least 6 months; diagnosis made by a skilled physician; no better explanation for diagnosis |
|
|
Term
| Where do you see MS plaques at autopsy? |
|
Definition
| within deep white matter and periventricular areas |
|
|
Term
| How do MS plaques look when stained with Luxol fast blue stain? |
|
Definition
| Luxol fast blue stains normal myelin blue; damaged areas (demyelinated) are white |
|
|
Term
| What do you see histologically when looking at a MS plaque? |
|
Definition
| robust inflammatory response within plaque, especially at edges; monocytes within a blood vessel is a perivascular cuff, show staining for T cell and B cells and macrophages but NOT neutrophils; some cells enter the brain parenchyma |
|
|
Term
| Normal axons are contiguous. In MS, axons and nerve cells are damaged. What would you see upon staining? |
|
Definition
| staining is disrupted with an abnormal spheroid at end of axon- indicative of a transected axon |
|
|
Term
| What triggers symptoms of MS? |
|
Definition
| inflammation that leads to demyelination that leads to axonal nerve loss |
|
|
Term
| What does myelin allow for? |
|
Definition
| very fast saltatory conduction down an axon |
|
|
Term
| What occurs in an MS patient as a result of demyelination? |
|
Definition
| neurologic dysfunction due to conduction impairment along partially or completely demyelinated fibers; these demyelinated fibers are temperature sensitive and less efficient with increasing temperature; decree of edema following breakdown of myelin also contributes to severity of symptoms |
|
|
Term
| What is the pathogenesis of MS? |
|
Definition
| cause uncertain but it is an immune-mediated inflammatory disease of the CNS; leukocytes penetrate BBB and secrete inflammatory cytokines; T cells, B cells, and macrophages orchestrate the autoimmune attack against myelin antigens; may develop in genetically susceptible individuals who are exposed to undefined "triggers" |
|
|
Term
| What do TH1 cells do in MS? TH2? |
|
Definition
| TH1 are activated in systemic circulation and cross BBB to initate an autoimmune response in the CNS; they stimulate B cells to make Ab and macrophages to make substance that demyelinate or cause axonal damage; TH2 cells regulate the process and reudce the pro-inflammatory response of the TH1 cells; CNS becomes its own immune organ in MS patients (like a lymph node) |
|
|
Term
| How many people in the US are affected by MS? In whom is MS typically diagnosed? |
|
Definition
| approx 350,000 in the US affected; most commonly diagnosed in young adults between 20-40; 2/3 of people diagnosed with relaspsing remitting MS (RRMS) are women but gender distribution is about equal in primary progressive MS (PPMS) |
|
|
Term
| What is the typical age of onset for MS? By how much do women outnumber women? Is there any geographic relationshpi to MS? What is the incidence of MS? What is the prevalence? |
|
Definition
| peak age of onset is 3rd decade of life with age range 15-45; 70% of those diagnosed are women by a ratio of 2:1 over men; studies support a copmlex interaction with environmental and genetic factors with incidence increasing with distance from the equator; incidence is 8500-10,000 new cases per year with 350,000 cases in the US total |
|
|
Term
| What are the 2 categories of MS? |
|
Definition
| relapsing and progressive |
|
|
Term
| Describe relapsing forms of MS. |
|
Definition
| exacerbations followed by complete or incomplete recovery; slow, inconsistent accumulation of disability occurs in the majority of patients |
|
|
Term
| Describe progressive forms of MS. |
|
Definition
| steady progression of disabilty with few or no exacerbations; if progressive from onset, MS falls into this category; gender distribution is equal; patients usually develop spastic paraparesis over a period of years; they will have evidence of corticospinal dysfunction (spasticity, weakness), sensory disturbance, urinary symptoms ("long tracts of the CNS symptoms") |
|
|
Term
| Do MRI and CSF of progressive MS look any different than relapsing MS? |
|
Definition
| no- work up looks the same, yet progressive patients never relapsed |
|
|
Term
| Is progressive MS easy to treat? |
|
Definition
| very difficult to treat with no FDA approved medications to treat progressive MS |
|
|
Term
| What do MS medicines treat? |
|
Definition
|
|
Term
| Can patients develop a progressive MS after having a relapsing MS? |
|
Definition
| yes- then it is called secondary progressive MS |
|
|
Term
| percent of patients presenting with relapsing remitting MS at onset? |
|
Definition
|
|
Term
| Is it common for RRMS patients to develop secondary progressive MS? |
|
Definition
| yes- a large number of patients progress in this way- they have significant disability so early treatment with an immunomodulating is crucial |
|
|
Term
| How many patients need walking aids within 15 years of diagnosis? |
|
Definition
|
|
Term
| What is the natural history of benign MS? |
|
Definition
| benign MS: patients have few relapses and never progerss (rare) |
|
|
Term
| What is the natural history of secondary progressive MS? |
|
Definition
| the number of plaques increases within the CNS and patients worsen even when the relapses stop |
|
|
Term
| What is the natural history of PPMS? |
|
Definition
| patients worsen without relapses; usually they lose ability to walk due to spastic paraparesis and other symptoms referable to CNS system that affect gait (balance, sensory input, etc0 |
|
|
Term
|
Definition
| in any combination: weakness, numbness, fatigue, vision problems, slurred speech, poor coordination, short-term memory loss, depression, bladder and bowel dysfunction, in severe cases- partial or complete paralysis |
|
|
Term
| What are some common demylinating syndromes you see with MS? Are theyacute or subacute symptoms? |
|
Definition
| optic neuritis, myelitis, and brainstem syndromes; they are subacute at onset (separating them from stroke which is acute and neurodegenerative diseases like PD which is chronic) |
|
|
Term
| Describe optic neuritis as related to MS. |
|
Definition
| unilateral, retrobulbar pain; no retinal exudates, disc hemorrhage infrequent, some recovery |
|
|
Term
| Describe myelitis as related to MS. |
|
Definition
| partial sensory >motor, band-like pressure; Lhermitte's sign; bowel and bladder sx are common; acute dystonias |
|
|
Term
|
Definition
| clincial signs and symptoms; MRI (brain, cervical, thoracic, and/or lumbar; gadolinium enhanced are best to evaluate progression); spinal tap (elevated myelin basic protein, oligoclonal banding); evoked potentials (measures brain's response to visual, auditory, sensory stimuli) |
|
|
Term
| what are oligoclonal bands? What do they suggest? |
|
Definition
| markers for MS are increased IgG index and presence of oligoclonal bands; oligoclonal ands are IgGs of similar size that are not normally present in normal CSF (they are present in serum); suggest MS in a patient w/no other isgns of systemic illness (may also be elevated in lyme disease, syphilis, lupus) |
|
|
Term
| What is a visual evoked response (in MS)? |
|
Definition
| can assist in diagnosing MS; flash light in front of a patient (takes 100 msec for light to pass from retina through optic nerve and chiasm to occipital cortex); wave that results is calledthe P100; if optic nerve is demyelinated, there is a delay of P100 or copmlete absence |
|
|
Term
| What are other evoked responses (in MS)? |
|
Definition
| measure how long it takes for a click to be heard from ear to auditory cortex (brainstem evoked response), how long for an electrical stimulus to travel from finger and toes to sensory cortex via ascending sensory fibers (somatosensory evoked response), demyelination of these pathways shows abnormal wave forms |
|
|
Term
| What is an APD consisten with? |
|
Definition
| demyelination and axon damage on the side of the lesion |
|
|
Term
| Describe a classic MS lesion on MRI. |
|
Definition
| ovoid, deep white matter, periventricular, hyperintense |
|
|
Term
| What is common in the corpus callosum and why? |
|
Definition
| MS plaques b/c the CC is heavily myelinated |
|
|
Term
| Does one MS elapse event, accompanied by plaques on MRI mean the patient has MS? |
|
Definition
| classically, MS patients must be diagnosed using time and space as criteria. Historically you wait for a second relapse and examine for new neurologic deficits; but MRI can now be used diagnositcally- so if a patient had 5 lesions and then 3 months later had 6 lesions, that patient has now had a 2nd attack ("time") OR if a patient has optic neuritis (lesion of optic nerve) and 15 lesions within her brain, she has 2 lesions in 2 different areas of the CNS, satisfying "space" |
|
|
Term
| What are some conditions to exclude in suspected MS? |
|
Definition
| vasculopathies and vasculitis; structural lesions; inherited leukodystrophies; infections; other (B12 deficiences, neuro sarcoid, Behcet's disease, Sjogren's syndrome), Acute disseminated encephalomyelitis |
|
|
Term
| What should you use MRI for in MS diagnosis? |
|
Definition
|
|
Term
| What MRI should you order for MS? |
|
Definition
| brain MRI: T1, T1+gad, T2 (post fossa) flair, in axial and saggital view; spine MRI; repeat in 3-12 months if necessary |
|
|
Term
| What drugs are used to treat specific MS symptoms? |
|
Definition
| steroids (acute relapse); baclofen; tizanidine; amantadine; modafinil; antidepressants |
|
|
Term
| DO steroids alter the natural history of MS? |
|
Definition
|
|
Term
| drugs that treat underlying disease in MS? |
|
Definition
| interferon beta-1a; interferon-beta- 1b, glatiramer acetate, mitoxantrone, natalizumab, phase 2 trial data |
|
|
Term
| What are your treatment options for a MS relapse? |
|
Definition
| none b/c at least 1/3 of relapses resolve with no intervention; steroids for severe neurlogic deficit |
|
|
Term
| What is internuclear opthalmoplegia? |
|
Definition
| results from damage to the medial longitudinal fasciculus; lesion is on the side of the adduction deficit; can be bilateral or unilateral; most commonly seen in MS |
|
|
Term
| Where do cell bodies of origin for sensory nerve fibers reside? |
|
Definition
|
|
Term
| How do sensory and motor nerve fibers exit the spinal cord? |
|
Definition
| they exit in small groups called rootlets which fuse to form roots |
|
|
Term
| How many pairs of nerve roots come from the spinal cord? |
|
Definition
| 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal |
|
|
Term
| Where does the spinal cord end? What do the nerve roots that have not yet exited do? |
|
Definition
| spinal cord ends at conus medullaris between L1 and L2 vertebral bodies; nerve roots that have not yet exited continue inferiorly and exit at their respective formina, forming the cauda equina |
|
|
Term
| What do dorsal and ventral rootlets fuse to form? |
|
Definition
|
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Term
| What do dorsal and ventral roots fuse to form? |
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Definition
| fuse within their respective intervertebral foramen, forming a mixed spinal nerve (MSN) |
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Term
| Upon exiting the intervertebral foramen, what does the MSN give off? |
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Definition
| a posteriorly directed branch, the posterior primary ramus, and continues as the anterior primary ramus- these are the proximal elements of the brachial plexus |
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Term
| Describe the brachial plexus (divisions, root, trunk, etc). |
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Definition
| C5-T1 nerve roots (anterior rami); upper/middle/lower trunks; 6 divisions lie behind the clavicle--> lateral, posterior, medial cords |
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Term
| What is the sensory domain of a PNS element? |
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Definition
| sensory domain: skin region innervated by sensory nerve fibers contained within a nerve root; dermatom is a sensory domain of a root |
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Term
| What is a muscle domain of a PNS element? |
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Definition
| muscle innervated by motor nerve fibers contained within a nerve root; mytome is the motor domain of a root |
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Term
| What are the 2 most common causes of radiculopathies? |
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Definition
| disk herniation and degeneration (cervical radiculopathies: HNP C7>C6 and spondylosis C5 and C6 most frequent) AND lumbosacral radiculopathies (95%HNP affect either L5 or S1) |
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Term
| What is the frequency of spondylosis? |
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Definition
| by age 60 years, 70% women and 85% of men; after age 70, 93% of women and 97% men |
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Term
| Why does traction tend to produce rupture at C5 and C6 MSN? |
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Definition
| C5 and C6 MSNs are tehtered to the transverse process by connective tissue |
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Term
| Why does traction tend to cause avulsion injury at C8 and T 1 nerve roots? |
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Definition
| these roots are typically NOT tethered, resulting in avulsion injury from traction |
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Term
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Definition
| C7 MSN varies in its degree of tethering |
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Term
| What are the clinical features of radiculopathy? |
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Definition
| pain the historical hallmark: paracentral axial pain that is radiation in nature, sharp, stabbing, hot, electric; often aggravated by maneuver's that stretch the root |
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Term
| What are some of the maneuvers that aggravate radiculopathy? |
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Definition
| neck extension is best maneuver for upper extremity; neck rotation, and spurling's maneuver may also be used for cervical radiculopathies; for lower extremity, SLR (if L5 or S1 suspected) and reverse SLR (if L4 is suspected); also crossed- SLR may be more specific |
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Term
| Other than maneuvers that stretch the root, how else might you physically examine a radiculopathy? |
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Definition
| spinal column percussion: may ID disorders of the VBs- metastic disease, epidural abscess, osteomyelitis |
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Term
| What are some other clinical features of radiculopathy (other than classic hallmark of pain)? |
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Definition
| weakness and atrophy (motor nerve fibers, myotomal distribution); paresthesias and sensory loss (sensory nerve fibers, dermatomal distribution); muscle stretch reflexes (diminished or absent) |
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Term
| What are the different types of spondylosis? |
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Definition
| common in greater than 50 year old age range; cervical: myeloradiculopathy (spinal canal stenosis); lumbosacral: neurogenic claudication (ambulation -->LE pain and weakness) and cauda equina syndrome) |
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Term
| What do you do when confronted with a patient with new onset lower back pain? |
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Definition
| Step 1: exclude emergencies- require immediate attention or diagnostic evaluation for etiology, spinal cord compression, cauda equina syndrome; possible causes include: fractures or dislocation due to trauma is the major cause in young patients, minor cause in elderly; bone disease such as osteoporosis, osteomalacia, paget disease, corticosteroid therapy, congenital anomalies; infection (myelitis) such as fever, immunosuppressed status, IVDA, spinal surgery, penetrating wound; neoplasm such as history of cancer, constitutional symptoms (like weight loss), pain at rest, neurological deficit (cauda equina localization) |
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Term
| In patients with new onset lower back pain, why is addressing the etiology so pertinent? |
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Definition
| neoplastic processes may progress rapidly not be functionally reversible if not recognized and treated early; myelitis is a neurologic emergency; w/fractures or bone disease: spinal column instability puts the cord at risk |
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Term
| What are some pertinent positives in the history of a patient with new onset lower back pain? What conditions are associated with these positives? |
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Definition
| pain at rest (neoplasm, infection, primary bone disease); pain that causes writhing(neoplasm, visceral disease- ulcers, pancreatic disease); fever (vertebral osteomyelitis, subacute bacterial endocarditis); acute pain in a cancer patient (metastasis- epidural spinal cord compression); urinary incontinence or retention (cauda equina syndrome, myelopathy); pain increases with spinal extension and decreases with flexion (spinal stenosis) |
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Term
| What do standing and walking cause in regards to spinal flexion/extension? Sitting? |
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Definition
| standing and walking cause spinal extension and narrow intervertebral foramina while sitting causes spinal flexion and expansion of intervertebral foramina- walking uphill is easier than downhill; bicycling is easier than walking |
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Term
| What do you do to evaluate a patient with suspected radiculopathy? |
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Definition
| history and exam are most important- sw/spinal cord compression, determine the sensory level, anal tone, fecal or urinary incontinence, check cutaneous reflexes (abdominal, bulbocavernosus, anal wink, cremaster); cauda equina syndrome; plain radiographs, CT (+/- myelography), MRI |
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Term
| What are you looking for on plain radiographs in a suspected radiculopathy patient? |
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Definition
| assess VBs for body abnormalities (fracture, neoplasm, congenital deformity); oblique views (spondylosis and spondylolisthesis); flexion and extension views (assess spinal stability) |
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Term
| What are you using CT for in a radiculopathy patient? |
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Definition
| useful for body detail but invasive; adding contrast die (myelography) gives enhancement of spinal cord and root visualization |
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Term
| What are you using MRI for in a radiculopathy patient? |
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Definition
| most useful imaging modality for assessing anatomic structure; superior to CT for all spine conditions; multiplanar; greater contrast sensitivity (tumor and infection detection); noninvasive; non-ionizing radiation; gadolinium contrast (scar tissue versus recurrent disk protrustion) |
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Term
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Definition
| most helpful study for assessing nerve fiber function; more sensitive than clinical exam and false positive studies are extemely unlikely; yields physiologic infromation; complements MRI (anatomic changes with high false positive rate) |
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Term
| What does EDX testing do? |
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Definition
| assesses sensory and motor nerve fibers; assesses muscle fibers; identifies demyelination and axon loss; localizes the disorder; generates differential diagnosis or the actual diagnosis; determines severity; determines prognosis; dictates management and follow up |
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Term
| How do you treat radiculopathy? |
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Definition
| conservatively! Most acute radiculopathies improve within 6 weeks; bed rest 0-2 days, if required; do daily activities, avoiding those that exacerbate pain; physical therapy (heat, cold, ultrasound, massage; stretching exercises; ergonomic education); medications (NSAIDs, prednisone, benzos); nerve blocks |
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Term
| Why would you do surgery for radiculopathy? |
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Definition
| certain etiologies suggest surgery- neoplasm; spinal instability; severe or progressive weakness; spinal cord compression; cauda equina syndrome; sphincter or sexual dysfunction; incapacitating neurogenic claudication; intractable pain (**ill advised if isolated pain w/ negative imaging) |
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Term
| What are the elements of the brachial plexus? |
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Definition
| anterior primary rami; trunks; divisions; cords; terminal nerves |
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Term
| The brachial plexus is divided into a supraclavicular and infraclavicular plexus. What does this mean for lesions? |
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Definition
| from roots --> trunks, little nerve fiber rearrangement occurs so trunk lesions resemble root lesions clinically; after divisions -->cords, terminal nerves are given off, making cord lesions resember nerve lesions clincally |
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Term
| What do C5 and C6 join to form? C7? C8 and T1? Basically, how is the brachial plexus formed? |
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Definition
| C5+C6= upper trunk, C7=middle trunk, and C8+T1=lower trunk; each trunk becomes 2 divisions, one anterior and one posterior; anterior divisions of upper and middle trunk join to form lateral cord; 3 posterior divisions form the posterior division; anterior division of lower trunk continues as medial cord; terminal nerves derive from cords |
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Term
| Are the muscle domains of the brachial plexus definable? |
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Definition
| yes, they are derived from the mytome charts |
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Term
| What is the muscle domain of the upper trunk? |
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Definition
| C5 mytome+C6 myotome=dorsal scapular and long thoracic nerves |
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Term
| From where do sensory nerve fibers constituting lateral antebrachial cutaneous nerve come? |
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Definition
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Term
| Which sensory nerve fibers innervate the thumb? |
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Definition
| sensory nerve fibers of median nerve that derive from C6 DRG |
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Term
| From where do the sensory nerve fibers making up superficial radial nerve come? |
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Definition
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Term
| The nerve fibers that innervate the second digit come from? |
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Definition
| sensory nerve fibers of median nerve that derive mostly from C7 DRG |
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Term
| Digit 3 is innervated by? |
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Definition
| sensory nerve fibers of median nerve derived from C7 DRG |
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Term
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Definition
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Term
| The medial antebrachial cutaneous nerve comes from? |
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Definition
| sensory nerve fibers derived from T1 DRG |
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Term
| When presented with a patient w/neuropathy, what information should you gather for a differential diagnosis? |
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Definition
| distribution and symmetry (generalized, multiple mononeuropathies, mononeuropathies); sensory or motor fibers; demyelinating or axon loss; temporal course |
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Term
| Describe stocking-glove distribution. |
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Definition
| axonal loss, sensory earlier and more profoundly than motor |
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Term
| Describe a situation with generalized motor with distal sensory neuropahty? |
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Definition
| acquired demyelination, acute-subacute (AIDP-SIDP-CIDP) |
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Term
| Describe a situation with generalized distal motor>sensory neuropathy. |
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Definition
| hereditary dysmyelination, chronic |
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Term
| What is the etiology in the majority of acquired, slowly progressive, sensory > motor, stocking glove neuropathies? |
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Definition
| toxic metabolite : #1 diabetes, #2 ethanol abuse |
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Term
| What do the majority of acute to subacute-onset generalized weakness w/ stocking globe sensory abnormalities represent? |
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Definition
| typically represent acquired demyelinating neuropathy |
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Term
| What do the majority of chronic, stocking glove distribution weakness that is out of proportion with degree of sensory loss represent? |
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Definition
| usuallyr elated to hereditary dysmyelination |
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Term
| What are some examples of multiple mononeuropathies (multifocal presenation)? |
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Definition
| ischemic (vasculitis, diabetic amyotrophy); inflammatory/immune-mediated (neuralgic amyotrophy, sarcoidosis); infectious (leprosy, lyme disease, CMV); genetic (HNPP, hereditary enuralgic amyotrophy); mechanical (entrapments); neoplastic |
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Term
| List the cutaneous and motor branches of radial nerve. |
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Definition
| posterior cutaneous nerve of arm; posterior cutaneous nerve of forearm; triceps and anconeus muscles; brachioradialis and ECR longus; gives off SRN and continues as PIN; supinator; ECR brevis; EDC; EDM; ECU; APL; EPL; EPB; EIP |
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Term
| List the cutaneous and motor branches of the median nerve. |
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Definition
| pronator teres and FCR; palmaris longus and FDS; anterior interosseus nerve (FPL, FDP-D2 and D3; pronator quadratus); palmar cutaenous nerve; thenar muscles and lumbricals 1 and 2; palmar digital nerves |
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Term
| List the cutaneous and motor branches of the ulnar nerve. |
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Definition
| FCU and FDP-D3 and D4; palmar cutaneous nerve; dorsal cutaneous nerve; superficial terminal nerve; palmaris brevis; hypothenar muscles; lumbriclas 3 and 4; interossei; adductor pollicis; FPB (deep head) |
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Term
| List the cutaneous and motor branches of the common peroneal nerve. |
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Definition
| lateral sural cutaneous nerve; lateral cutaneous nerve of calf (superficial peroneal nerve- peroneus longus and brevis, cutaneous distribution; deep peroneal nerve-TA, EHL, EDL, EDB, cutaneous distribution) |
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Term
| List the cutaneous and motor branches of the tibial nerve. |
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Definition
| medial sural cutaneous nerve; gastrocnemius; soleus (popliteus, plantaris); tibialis posterior; FDL; FHL (medial plantar nerve- AH, FDB, FH, lumbricals 1 and 2, cutaneous distribution; lateral plantar nerve- ADM, FDM, adductor hallucis, interossei, lumbricals 3 and 4, cutaneous distribution; medial calcaneal nerve) |
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Term
| Where does Wallerian degeneration occur? What does it allow? |
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Definition
| occurs from the disruption site, distally; it permits EDX testing to differentiate intraspinal canal lesions (ex: ALS, radiculopathies) from plexopathies and neuropathies |
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Term
| How do you identify focal demyelination? |
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Definition
| stimulating and recording electrodes must be placed so that they straddle the 2 sides of the lesion |
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Term
| What does uniform slowing (EMG) do? |
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Definition
| maintains the shape of recorded waveform |
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Term
| What does nonuniformed slowing do (EMG)? |
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Definition
| affects the CMAP morphology |
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Term
| What happens with demyelinating conduction block (DMCB)? |
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Definition
| demyelination is so severe that the impulses cannot propagate across the lesion site; lesions may be partial or complete |
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Term
| What does axon disruption do? |
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Definition
| induces distal degenerative changes (wallerian degeneration) that renders the distal segment of the disrupted nerve fiber unexcitable; process occurs over 3-7 day period |
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Term
| How long does it take for axon disruption to induce distal degenerative changes? |
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Definition
| 3-7 days; until then, the distal stump still conducts and mimics demylinating conduction block |
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Term
| Why is it important that demyelinating conduction block can look much like axon disruption on EMG? |
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Definition
| prognoses vary significantly so the timing of EDX assessment is extremely important to provide the EDX consultant |
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Term
| What sort of prognosis does does demyelinating conduction block have, as compared to axon disruption? |
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Definition
| DMCB has an excellent prognosis but axon disruption does not; because these can look similar on on nerve conduction study, it is important to note the onset of weakness |
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Term
| Do denervated muscle fibers discharge? |
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Definition
| yes, they can generate spontaneous discharges- see insertional postiive waves and fibrillation potentials |
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