Term
| What cells secrete thyroid hormones? |
|
Definition
| follicular cells of the thyroid |
|
|
Term
| What cells secrete calcitonin? |
|
Definition
| parafollicular cells of the thyroid |
|
|
Term
| Over 99% of thyroid hormones (T3 and T4) are bound to a protein, _______________. |
|
Definition
| thyroid-binding globulin (TBG) |
|
|
Term
| What thyroid hormone is active? |
|
Definition
| that not bound to TBG (only about 1%) |
|
|
Term
| What makes up the bulk of active thyroid hormone? |
|
Definition
|
|
Term
| How does thyroid hormone affect metabolism? |
|
Definition
| enters tissues and increases oxygen consumption and heat production to increase metabolic rate |
|
|
Term
| What specific effects does thyroid hormone have? |
|
Definition
increases heart rate
increases cardiac output
increases gut motility
increases bone turnover
increases gluconeogenesis
increases muscle protein turnover |
|
|
Term
| What is the first test that should be done when screening for thyroid disorders? |
|
Definition
|
|
Term
| screening guidelines for thyroid disorders |
|
Definition
-TSH on all infants at birth and 2 weeks
American Thyroid Association says TSH on everyone over 35 yo every 5 years
American Association of Clinical Endocrinologists says TSH on all women by 50 yo and pregnant/postpartum women |
|
|
Term
|
Definition
| decreased production of thyroid hormone (T3, T4) |
|
|
Term
|
Definition
-mostly unknown
-exogenous dopamine suppresses TSH
-lithium decreases thyroid hormone synthesis
-amiodarone |
|
|
Term
| risk factors for hypothyroidism |
|
Definition
female
Caucasian
family history
increasing age
autoimmune disease |
|
|
Term
| clinical presentation of congenital hypothyroidism (cretinism) |
|
Definition
feeding problems
hypotonia
edema of face/hands |
|
|
Term
| What does cretinism (congenital hypothyroidism) lead to? |
|
Definition
mental retardation
short stature
delayed puberty
possible infertility |
|
|
Term
| clinical presentation of adult onset hypothyroidism |
|
Definition
fatigue/lethargy
weight gain
cold intolerance
dry skin
constipation
coarse hair/hair loss
menstrual abnormalities
myalgias/weakness |
|
|
Term
| What physical exam findings are consistent with hypothyroidism? |
|
Definition
-thinning of lateral third of eyebrows
-coarse, thick, dry skin
-coarse, brittle hair
-dull expression with thick tongue and lips
-slowed mentation
-delayed relaxation phase of DTRs
-muscle weakness
-myxedema (late stage) |
|
|
Term
| What is myxedema related to? |
|
Definition
| high levels of TSH receptor stimulation |
|
|
Term
| cutaneous and dermal edema secondary to increased deposition of connective tissues |
|
Definition
|
|
Term
| What is caused by interstitial accumulation of hydrophilic mucopolysaccharides leading to lymphedema? |
|
Definition
|
|
Term
| complications of untreated hypothyroidism |
|
Definition
CHF
increased susceptibility to infection
megacolon
psychoses ("myxedema madness")
infertility/miscarriage
sellar enlargement
myxedema coma (medical emergency) |
|
|
Term
| What causes the sellar enlargement associated with hypothyroidism? |
|
Definition
|
|
Term
| What findings are consistent with myxedema coma? |
|
Definition
hypothermia
hypoventilation
hyponatremia, hypoglycemia
hypoxia
hypercapnea
hypotension |
|
|
Term
| What often induces a myxedema coma? |
|
Definition
|
|
Term
| Who most often gets myxedema coma? |
|
Definition
|
|
Term
| treatment of myxedema coma |
|
Definition
IV levothyroxine sodium
blankets
possibly intubation
ID and treatment of precipitating factor |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| TSH level in primary hypothyroidism |
|
Definition
|
|
Term
| free T4 level in primary hypothyroidism |
|
Definition
|
|
Term
| TSH level in central hypothyroidism |
|
Definition
| low-normal (in the setting of low free T4) |
|
|
Term
| free T4 level in central hypothyroidism |
|
Definition
|
|
Term
| What causes central hypothyroidism? |
|
Definition
| pituitary or hypothalamic disorder |
|
|
Term
| treatment of hypothyroidism |
|
Definition
| L-thyroxine (Synthroid, Levothroid, Levoxyl) |
|
|
Term
| How should levothyroxine be taken? |
|
Definition
| in the morning, 1 hour before food |
|
|
Term
| How should you initiate treatment with levothyroxine? |
|
Definition
start 50-100 mcg
titrate every 4-8 weeks based on TSH |
|
|
Term
| How should levothyroxine treatment be initiated in a pregnant woman? |
|
Definition
|
|
Term
| How should levothyroxine treatment be initiated in the elderly? |
|
Definition
|
|
Term
| How would you treat a patient with a TSH >8 but free T4 and free T3 are normal? |
|
Definition
|
|
Term
| clinical syndrome due to elevated thyroid hormones |
|
Definition
|
|
Term
| increased production of thyroid hormone |
|
Definition
|
|
Term
| What are the symptoms of thyrotoxicosis due to? |
|
Definition
effects of hormones
increased sensitivity to catecholamines |
|
|
Term
| risk factors for hyperthyroidism |
|
Definition
age 20-60 (20-40 for Graves')
females
Caucasians and Hispanics
family history |
|
|
Term
| What history findings are consistent with hyperthyroidism? |
|
Definition
heat intolerance
anxiety
increased sweating
sleep disturbances
weakness/fatigue
muscle cramps
frequent BMs
palpitations or angina pectoris
irregular periods
decreased libido, impotence, gynecomastia, decreased sperm count |
|
|
Term
| What physical exam findings are consistent with hyperthyroidism? |
|
Definition
irritability
nervousness/restlessness
weight loss
muscle weakness
tremors
perspiration
thin and brittle hair
tachycardia
atrial fibrillation (late stage)
exophthalmos
hyperreflexia |
|
|
Term
| Why does exophthalmos occur in patients with hyperthyroidism? |
|
Definition
| TSH receptor stimulation on fibroblasts behind the eyes causes increased glycosaminoglycan deposition |
|
|
Term
| What can exophthalmos cause? |
|
Definition
-diplopia (due to extraocular muscle entrapment)
-optic nerve compression
-corneal drying (due to lid lag) |
|
|
Term
| Exophthalmos is often coexistent with ____________ ______. |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What causes Graves' disease? |
|
Definition
| autoantibodies stimulate TSH receptors, leading to enlarged thyroid and excess thyroid hormone |
|
|
Term
| What will be present in the serum of a patient with Graves' disease? |
|
Definition
| thyroid-stimulating immunoglobulins (TSI) |
|
|
Term
| clinical features of Graves' disease |
|
Definition
goiter
pretibial myxedema
exophthalmos |
|
|
Term
| What is Graves' disease associated with? |
|
Definition
other autoimmune diseases
elevated ANA |
|
|
Term
| What would a thyroid uptake scan show in a patient with Graves' disease? |
|
Definition
| diffusely increased uptake |
|
|
Term
| Toxic adenomas of the thyroid are _________. |
|
Definition
|
|
Term
|
Definition
| single toxic adenoma in the thyroid |
|
|
Term
| What would the labs show in a patient with a toxic adenoma? |
|
Definition
low TSH
markedly elevated T3
mildly elevated T4
no TSI in serum |
|
|
Term
| What would a thyroid uptake scan show in a patient with a toxic adenoma? |
|
Definition
| one or more "hot" nodules |
|
|
Term
|
Definition
| ingestion of lots of thyroxine |
|
|
Term
|
Definition
| iodine-induced thyrotoxicosis |
|
|
Term
| What condition can occur in some patients with goiter who are given iodine? |
|
Definition
|
|
Term
|
Definition
| ovarian teratoma that contains thyroid tissue and secretes thyroid hormone |
|
|
Term
| High levels of _____ can cause hyperthyroidism. |
|
Definition
|
|
Term
| TSH level in primary hyperthyroidism |
|
Definition
|
|
Term
| free T3 level in primary hyperthyroidism |
|
Definition
|
|
Term
| free T4 level in primary hyperthyroidism |
|
Definition
|
|
Term
| TSH level in central hyperthyroidism |
|
Definition
| normal-high (in presence of high free T4) |
|
|
Term
| free T3 level in central hyperthyroidism |
|
Definition
|
|
Term
| free T4 level in central hyperthyroidism |
|
Definition
|
|
Term
| What differentiates Graves' from thyroiditis? |
|
Definition
| increased iodine uptake in RAI scan with Graves' |
|
|
Term
| What beta blocker is used in the treatment of hyperthyroidism for symptomatic relief? |
|
Definition
|
|
Term
| What drugs block thyroid hormone synthesis? |
|
Definition
| thioureas (methimazole, propylthiouracil) |
|
|
Term
| What is the drug of choice for hyperthyroidism in pregnancy? |
|
Definition
|
|
Term
| What is the treatment of choice for Graves' disease? |
|
Definition
|
|
Term
| What needs to be done before treating a patient with radioactive iodine? |
|
Definition
| pre-treat with anti-thyroid meds |
|
|
Term
| What treatment is useful for solitary toxic adenoma of the thyroid? |
|
Definition
|
|
Term
| What surgical treatment can be used for hyperthyroidism? |
|
Definition
|
|
Term
| What needs to be done prior to doing a thyroidectomy? |
|
Definition
| pre-treat with anti-thyroid meds |
|
|
Term
| What complications are associated with thyroidectomy? |
|
Definition
hypoparathyroidism
recurrent laryngeal nerve palsy |
|
|
Term
| What is the treatment of choice for multinodular goiter? |
|
Definition
|
|
Term
| What treatment can be given for myxedema? |
|
Definition
|
|
Term
| What referral needs to be made in a patient with hyperthyroidism? |
|
Definition
|
|
Term
| What will patients need to be on for the rest of their life if they have a thyroidectomy? |
|
Definition
| thyroid supplements (levothyroxine) |
|
|
Term
| acute, life-threatening, hypermetabolic state in individuals with thyrotoxicosis |
|
Definition
|
|
Term
| symptoms of thyroid storm |
|
Definition
fever
tachycardia
hypertension
confusion
delerium
n/v/d
sweating |
|
|
Term
| What is the most common cause of thyroid storm? |
|
Definition
|
|
Term
| How is a diagnosis of thyroid storm made? |
|
Definition
primarily clinical
no specific lab tests are available |
|
|
Term
| treatment of thyroid storm |
|
Definition
thioureas
beta blockers
steroids |
|
|
Term
| inflammation of the thyroid gland |
|
Definition
|
|
Term
| How does thyroiditis present? |
|
Definition
| initially as hyperthyroidism, but eventually results in hypothyroidism |
|
|
Term
|
Definition
|
|
Term
| What type of thyroiditis is a complication of septicemia? |
|
Definition
| suppurative thyroiditis (acute) |
|
|
Term
| symptoms of suppurative thyroiditis |
|
Definition
fever
redness over anterior neck
tenderness of thyroid |
|
|
Term
| How do you make a diagnosis of suppurative thyroiditis? |
|
Definition
|
|
Term
| How do you treat suppurative thyroiditis? |
|
Definition
|
|
Term
|
Definition
| De Quervain's thyroiditis |
|
|
Term
| How does postpartum thyroiditis present? |
|
Definition
| painless inflammation 2-6 months after childbirth |
|
|
Term
| How does De Quervain's thyroiditis present? |
|
Definition
fever
anterior neck pain
tender thyroid on exam |
|
|
Term
| Who is most often affected by De Quervain's thyroiditis? |
|
Definition
|
|
Term
| What is thought to be the cause of De Quervain's thyroiditis? |
|
Definition
|
|
Term
| What lab finding is consistent with De Quervain's thyroiditis? |
|
Definition
|
|
Term
| What would you expect to see with RAI uptake scan in a patient with De Quervain's thyroiditis? |
|
Definition
|
|
Term
| How would you treat De Quervain's thyroiditis? |
|
Definition
NSAIDs
levothyroxine
rarely, a short course of prednisone |
|
|
Term
| subacute lymphocytic thyroiditis |
|
Definition
|
|
Term
| Painless thyroiditis is most likely _________ in origin. |
|
Definition
|
|
Term
| How does painless thyroiditis present? |
|
Definition
| small goiter without tenderness |
|
|
Term
| What lab finding is consistent with painless thyroiditis? |
|
Definition
|
|
Term
| What would you expect to see with a RAI scan in a patient with painless thyroiditis? |
|
Definition
|
|
Term
| How do you treat painless thyroiditis? |
|
Definition
|
|
Term
| chronic lymphocytic thyroiditis |
|
Definition
|
|
Term
| What is the most common cause of goiter and hypothyroidism in the U.S.? |
|
Definition
|
|
Term
| What causes Hashimoto's thyroiditis? |
|
Definition
autoimmune
antibodies to thyroid peroxidase and thyroglobulin cause gradual destruction of follicles in the thyroid gland |
|
|
Term
| What characterizes Hashimoto's thyroiditis? |
|
Definition
| invasion of the thyroid tissue by lymphocytes |
|
|
Term
| How does Hashimoto's thyroiditis present? |
|
Definition
| symptoms of hyperthyroidism or hypothyroidism and goiter (non-tender) |
|
|
Term
| How is a diagnosis of Hashimoto's thyroiditis made? |
|
Definition
thyroid ultrasound to look for nodules
FNA biopsy shows lymphocytes and Hurthle cells |
|
|
Term
| How do you treat Hashimoto's thyroiditis? |
|
Definition
|
|
Term
|
Definition
| enlargement of thyroid gland |
|
|
Term
| What must be ruled out when you have a goiter? |
|
Definition
|
|
Term
|
Definition
| stimulation of the TSH receptor on the thyroid gland leads to hyperplasia of thyroid cells |
|
|
Term
| What causes an endemic goiter? |
|
Definition
|
|
Term
| A patient with a goiter can be... |
|
Definition
| euthyroid, hyperthyroid, or hypothyroid |
|
|
Term
| How do you treat endemic goiter? |
|
Definition
add iodine to diet
thyroxine supplementation to shrink goiter
thyroidectomy |
|
|
Term
| What causes a goiter in Graves' disease? |
|
Definition
| TSIs bind to TSH receptor, leading to excess thyroid hormone and goiter |
|
|
Term
| What causes a goiter in Hashimoto's thyroiditis? |
|
Definition
| autoimmune process destroys the normal thyroid tissue, hormone levels drop, and TSH increases |
|
|
Term
|
Definition
formation of thyroid cells
formation of T3 and T4 |
|
|
Term
| What would you expect labs to reveal in a patient with primary hypothyroidism? |
|
Definition
elevated TSH
suppressed free T4 |
|
|
Term
| What do you base your treatment with levothyroxine on in a hypothyroid patient? |
|
Definition
|
|
Term
| risk factors for thyroid cancer |
|
Definition
inherited genetic syndromes (MEN)
personal or family history of goiter
radiation exposure |
|
|
Term
| symptoms of thyroid cancer |
|
Definition
-palpable, firm, non-tender nodule
-hard and fixed nodules are more suspicious for malignancy than supple, mobile nodules
-usually painless
-infrequently: hoarseness, neck pain, enlarged lymph nodes, hemoptysis, dysphagia
-3% present with mets |
|
|
Term
| What does a decreased TSH suggest when working a patient up for thyroid cancer? |
|
Definition
| functioning nodule, which is typically benign |
|
|
Term
| Can low or high TSH rule out malignant disease? |
|
Definition
|
|
Term
| What is elevated serum calcitonin suggestive for? |
|
Definition
| medullary thyroid carcinoma (MTC) |
|
|
Term
| What lab tests should be done if you are suspicious for FMTC or MEN-2A or MEN-2B? |
|
Definition
| PCR-based assays for germline mutations in the RET proto-oncogene |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| What studies can be used to confirm a diagnosis of thyroid carcinoma? |
|
Definition
FNA biopsy
thyroid ultrasound
thyroid uptake scan |
|
|
Term
| What offers a worse prognosis for patients diagnosed with thyroid carcinoma? |
|
Definition
older age
male sex
more aggressive type : anaplastic
fast growing nodule
cervical LAD
bone/brain mets
large pulmonary mets
lack of I131 uptake into mets |
|
|
Term
| Treatment of thyroid cancer is __________. |
|
Definition
|
|
Term
| What complications are associated with surgical removal of the thyroid as treatment for thyroid carcinoma? |
|
Definition
recurrent laryngeal nerve injury
hypoparathyroidism |
|
|
Term
| What is done after surgery in a patient with thyroid carcinoma? |
|
Definition
| radioiodine scan for detection of metastatic disease followed by radioablation |
|
|
Term
| What conservative surgical treatment is used for thyroid cancer? |
|
Definition
| subtotal thyroidectomy (tissue opposite the side of malignancy is left in place) |
|
|
Term
| How is chemotherapy and radiation used for the treatment of thyroid cancer? |
|
Definition
| usually as adjunct (not very useful alone) |
|
|
Term
| What are the 4 main types of thyroid carcinoma? |
|
Definition
papillary carcinoma
follicular carcinoma
medullary carcinoma
anaplastic carcinoma |
|
|
Term
| What is medullary thyroid carcinoma broken down into? |
|
Definition
MEN 2A
MEN 2B
FMTC (familial medullary thyroid carcinoma) |
|
|
Term
| What is the most common type of thyroid malignancy? |
|
Definition
|
|
Term
| Papillary carcinoma can occur in association with ______________. |
|
Definition
| Gardner syndrome (familial adenomatous polyposis) |
|
|
Term
| Patients with papillary carcinoma usually have a history of what? |
|
Definition
|
|
Term
| Papillary carcinoma is a _________-growing tumor arising from the _________ cells. |
|
Definition
slow-growing
follicular (thyroxine-producing) |
|
|
Term
| Papillary carcinomas are/are not TSH sensitive. |
|
Definition
|
|
Term
| Where does papillary carcinoma have a high propensity to spread to? |
|
Definition
|
|
Term
| Although distant mets are rare with papillary carcinoma, where do they usually occur if they do? |
|
Definition
|
|
Term
| What is the second most common type of thyroid malignancy? |
|
Definition
|
|
Term
| How can follicular carcinoma spread? |
|
Definition
| via local invasion, lymphatics, or hematogenously |
|
|
Term
| Where does follicular carcinoma usually spread to? |
|
Definition
|
|
Term
| Follicular carcinomas are/are not TSH sensitive. |
|
Definition
|
|
Term
| What is another name for MEN 2A? |
|
Definition
|
|
Term
| What conditions is MEN 2A associated with? |
|
Definition
MTC
pheochromocytoma
hyperparathyroidism |
|
|
Term
| What conditions is MEN 2B associated with? |
|
Definition
MTC
pheochromocytoma
marfanoid habitus
ganglioneuromatosis |
|
|
Term
| What is the most common cause of mortality in patients with MEN syndromes? |
|
Definition
| medullary thyroid carcinoma (MTC) |
|
|
Term
| What cells are affected by medullary thyroid carcinoma? |
|
Definition
| C-cells (parafollicular cells), which produce calcitonin |
|
|
Term
| What is the mainstay of diagnosis for medullary thyroid carcinoma? |
|
Definition
| genetic testing (RET proto-oncogene mutations) |
|
|
Term
| What other lab finding besides genetic abnormalities is helpful in diagnosis medullary thyroid carcinoma? |
|
Definition
| elevated serum calcitonin |
|
|
Term
|
Definition
| total thyroidectomy with lymphatic dissection of the anterior compartment of the neck |
|
|
Term
|
Definition
| annual calcitonin and carcinoembryonic antigen (CEA) |
|
|
Term
| What is the most aggressive type of thyroid malignancy? |
|
Definition
|
|
Term
| median survival for anaplastic thyroid carcinoma |
|
Definition
|
|
Term
| What is the least common type of thyroid malignancy? |
|
Definition
|
|
Term
| symptoms of anaplastic carcinoma |
|
Definition
rapidly growing thyroid mass
hoarseness, dyspnea, vocal cord paralysis
palpable cervical mets early
at presentation, about half have distant mets (lungs, bones, brain) |
|
|
Term
| Where are anaplastic thyroid carcinomas believed to arise from? |
|
Definition
| pre-existing well-differentiated thyroid carcinoma |
|
|
Term
| treatment of anaplastic carcinoma |
|
Definition
-thyroidectomy with neck dissection
-tracheotomy often needed
-chemo/XRT |
|
|
Term
| How do most patients with anaplastic thyroid carcinoma die? |
|
Definition
| local airway obstruction or complications of pulmonary metastases within one year |
|
|
Term
| What is your next step if you palpate a thyroid nodule? |
|
Definition
|
|
Term
| What is your next step if you have a patient c/o painful neck but you do not feel a nodule? |
|
Definition
|
|
Term
| Cold nodules indicated an increased/decreased risk for malignancy. |
|
Definition
| increased (hypofunctioning) |
|
|
Term
| Hot nodules are usually __________ |
|
Definition
|
|
Term
| What findings on a thyroid ultrasound would cause greater suspicion for malignancy? |
|
Definition
irregular margins
intranodular vascular spots
microcalcifications |
|
|
Term
| Get FNA biopsy in any nodule greater than __________. |
|
Definition
|
|
Term
| When is fetal thyroid development complete? |
|
Definition
| term (even though thyroid hormone secreted by 18-week fetus) |
|
|
Term
| Does maternal thyroxine cross the placenta? |
|
Definition
|
|
Term
| What is dependent on maternal thyroxine, especially in the 2nd trimester? |
|
Definition
|
|
Term
| What needs to be done with a woman's hypothyroidism meds if she becomes pregnant and why? |
|
Definition
| need to be increased because pregnancy causes increased TBG |
|
|
Term
| What happens if maternal hypothyroidism is not treated before the 2nd trimester? |
|
Definition
| developmental delay (low IQ scores) |
|
|
Term
| What m ay occur during the first 4 months of pregnancy due to very high levels of hCG and why? |
|
Definition
| mild hyperthyroidism because hCG stimulates TSH receptors |
|
|
Term
| Free T4 is elevated in pregnancy, but _______ mg/dl is considered hyperthyroid. |
|
Definition
|
|
Term
| What antibodies could you check for in a patient you suspect Hashimoto's thyroiditis in? |
|
Definition
anti-thyroperoxidase
anti-thyroglobulin |
|
|
