Term
| What is the purpose of reference intervals? |
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Definition
| They account for the majority of healthy animals in the interval, providing a basis of comparison of abnormal animals. |
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Term
| How is a reference interval established for a test? What considerations are important in developing a reference interval? |
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Definition
| You have to define healthy, choose a population that is representative of the population. Most are based on 120 individuals where possible to get a representative group. It should create a bell shaped normal curve. |
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Term
| What is a 3rd standard deviation value? |
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Definition
| Most reference intervals only account for the mean +/- 2 standard deviations. A clinically healthy animal may have a value that is in the third standard deviation. |
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Term
| How do 3rd standard deviaions lead to false positives? |
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Definition
| 3rd standard deviation values are abnormal when compared to the reference interval, but may not indicate disease. |
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Term
| How do you differentiate 3rd standard deviation values versus a true abnormal value? |
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Definition
| One must look at the clinical signs/disease state seen in the animal and determine if the value would support those signs. Also the degree of change or changes compared to previous data from the same patient may be helpful. |
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Term
| What is biochemical profiling? |
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Definition
| Organizing of clinical chemistry data into groups of related or complementary tests |
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Term
| What are advantages of profiling? |
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Definition
| Consistant, orderly approach to data interpetation, integration of data, increase confidence in results, increase discrimination |
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Term
| What are disadvantages of profiling? |
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Definition
| Increased chance of false positives, eaconomics: more expensive |
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Term
| What's the blood flow through a glomerulus? |
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Definition
| Blood enters the afferent arteriole, goes through the glomerular capillary tuft. It leaves the glomerulus via the efferent arteriole and then through the vasa recta. |
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Term
| What are the different filtration layers of the glomerulus? |
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Definition
| Endothelium retains cells, the basement membrane of the glomerulus retains large proteins, slit pores retain most smaller proteins, between 6 and 9 nanometers. Sialoglycoprotein charge repels proteins. |
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Term
| What are the positive forces in urine formation in the glomerulus? |
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Definition
| Blood hydrostatic pressure |
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Term
| What are the negative forces to urine filtration in the glomerulus? |
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Definition
| Capsular hydrostatic pressure and blood oncotic pressure. |
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Term
| What's the relationship between blood supply through the glomerulus and the blood supply to the renal parenchyma? |
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Definition
| Blood that travels through the glomerulus is oxygenated blood. After leaving the glomerulus, blood travels through the vasa recta still oxygenated to supply the parenchyma of the kidney. |
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Term
| What is the primary renal panel comprised of? |
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Definition
| Blood Urea Nitrogen, creatinine, urine specific gravity, and the physical, chemical and urine sedimentation examination. |
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Term
| How does the GI tract affect blood urea nitrogen? |
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Definition
| Both a high protein diet (from breakdown of amino acids leading to ammonia and urea)and enteric hemorrhage lead to increased blood urea nitrogen. low protein diets and mild anorexia can lead to decreased BUN. Ruminants will typically have a lower BUN than creatinine because of bacterial degredation to create protein. |
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Term
| How does liver dysfunction afffect BUN? |
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Definition
| the liver is responsible for converting ammonia to urea, without a functional liver, BUN drops. |
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Term
| What occurs to BUN with renal failure/insufficiency? |
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Definition
| Renal failure leads to an accumulation of nitrogenous waste |
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Term
| How does polydypsia affect BUN? |
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Definition
| Polydipsia would increase fluid volume increasing GFR and decreasing BUN |
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Term
| What are causes of Secondary renal azotemia? Mechanism? |
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Definition
| ADH deficiency, tubules refractory to ADH, and loss of medullary osmotic gradient. |
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Term
| What tissues have an effect on serum levels of creatinine? |
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Definition
| Muscles produce creatinine when creatine is degraded during energy production and diffuses out ot cells. Minimal losses can occur through GI and sweat glands, however most is freely filtered in the glomerulus. There may be some secretion in male dogs and it is noted in goats. |
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Term
| What are the three major parts of a urinalysis? |
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Definition
| A urinalysis includes a physical examination of the urine, a chemical evaluation, and evaluation of the urine sediment |
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Term
| What urinary components contribute to urine turbidity/cloudiness? |
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Definition
| Cells (red blood cells and white and epithelial cells) proteins, mucus and other substances like lipid and crystals. |
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Term
| What is the mechanism of proteinuria with urinary tract hemorrhage? |
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Definition
| Hemorrhage in the kidney, ureters, bladder or urethra will leak red cells into the tract, which are present in the urine. This will give urine a red cloudy appearance and red cells will be seen in the sediment. |
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Term
| How does inflammation in the urinary tract cause proteinuria? |
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Definition
| Increased vascular permeability will allow inflammatory proteins to leak into the urine, as well as white cells.These cells will be in the sediment with WBC casts possible. |
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Term
| What is pre-renal physiologic proteinuria? |
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Definition
| Glomerular permiability is transiently increased, due to systemic inflammation making the glomerulus more leaky or other circulatory disorder. This would lead to a mild leakage of albumin in the urine, without WBCs in the sediment. |
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Term
| What is pre-renal overflow proteinuria? What is a mechanism for this? |
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Definition
| Reabsorption of the protein exceeds tubular reabsorption. Multiple myeloma is an example, where abnormal plasma cell tumor produces large numbers of small molecular weight light chain proteins. These are filtered in the glomerulus and into the urine, exceeding renal threshold. |
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Term
| What is glomerular protenuria? |
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Definition
| A problem in the glomerulus is disrupting the filtration barrier, causing a protein losing nephropathy. |
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Term
| What is tubular proteinuria? |
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Definition
| Decreased threshold for small molecular weight proteins due to tubular damage |
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Term
| What are the two main mechanisms for glucosuria? What are specific causes? |
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Definition
| There is overflow mechanism, where glucose in the urine exceeds the threshold for reabosorption (diabetes mellitus leading to hyperglycemia) and reduced threshold, where damage to the tubules (acute kidney injury) causes them to be unable to reabsorb normal amounts of glucose. |
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Term
| What is adequate urine concentration? What are the cut off values for dog, cat and other species? |
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Definition
| "Adequate" urine concentration refers to the ability to concentrate urine if there is a need to conserve water. adequate for a dog is 1.030, cat is 1.035 and other species is 1.025 |
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Term
| What are the three ketone bodies? Which is not routinely identified on the chemistry strip? |
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Definition
| Acetoacetate, beta-hydroxybutyrate (not tested for on the strip) and acetone. |
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Term
| Why are ketones formed in the body? |
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Definition
| Ketones are formed when the body is in a negative energy balance and mobilizing fat for energy. |
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Term
| What clinical conditions are associated with ketone formation? |
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Definition
| Diabetes mellitus leads to it when the animal cannot utilize glucose. Negative energy balance from pregnancy, lactation and starvation. |
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Term
| What other finding in the urinalysis would support ketonuria was due to diabetes mellitus? |
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Definition
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Term
| What does renal threshold mean? What is it for glucose in dogs cats and cows? |
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Definition
| Renal threshold refers to the ability of the proximal tubule to actively reabsorb a substance. For dogs, renal threshold of glucose is 180 mg/dl, cats 280 and cows 100 |
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Term
| What form of bilirubin is found in the urine? Why is this the only form found in urine? |
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Definition
| Conjugated bilirubin is found in the urine. It is water soluble. Unconjugated bilirubin is not soluble and therefore carried on albumin, which prevents it from being in the urine. |
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Term
| What form of bilirubin is detected on the test strip? What is the confirmatory tablet test called? |
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Definition
| The test detects conjugated bilirubin, and is confirmed using the ictotest. |
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Term
| What three things are detected by the urine occult blood test strip? What process causes them? |
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Definition
| Blood - from urinary tract hemorrhage. Hemoglobin - from overflow due to hemolysis or post urinary tract hemorrhage (if left to sit), and myoglobin from rhabdomyolysis |
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Term
| What happens to urine pH over time as the sample sits? |
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Definition
| CO2 evaporates over time as the sample sits out, meaning that overtime urine becomes more alkaline. |
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Term
| How can bacteria make a urine sample more alkaline? |
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Definition
| Bacteria that produce ureases break down urea into ammonia, making urine more alkaline. |
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Term
| what alterations are seen in the urine that has a more alkaline pH? |
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Definition
| Increases protein, causes precipitation of urine, and lysis of cells |
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Term
| Where are casts formed in the urinary tract? |
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Definition
|
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Term
| What mucoprotein forms the matrix for casts? |
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Definition
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Term
| What process is indicated by the presence of epithelial, granular and waxy casts? |
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Definition
| All indicate tubular degeneration, waxy casts may indicate slowed transit time |
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Term
| How is pyelonephritis distinguished from cystitis solely from urinalysis results? What additional information would also help support this. |
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Definition
| pyelonephritis would show WBC casts, due to inflammation in the glomerulus or tubules. Cystitis would show whole WBCs in a cystocentesis sample. Cystitis would not show an inflammatory leukogram, where pyelonephritis would. |
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Term
| What two urine crystals are naturally pigmented? |
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Definition
| Bilirubin and sulfa-type drugs (bizarre colors) |
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Term
| What urine crystals are commonly found in Dalmations? |
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Definition
| Ammonium urate/biruate and uric acid |
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Term
| What crystals are assoicated with ethylene glycol? |
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Definition
| Calcium oxalate monohydrate |
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Term
| What crystals are assoicated with hepatic insufficiency? |
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Definition
| Ammonium urate can suggest disorders in ammonia metabolism, shunts/liver mass |
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Term
| What crystals are associated with cholestasis? |
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Definition
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Term
| What "dumbbell" shaped crysta is seen in healthy large animals? |
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Definition
|
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Term
| What blood gas parameters are measured? |
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Definition
| pO2, pCO2, pH, HCO3, TCO2 |
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Term
| what blood gas parameters are calculated? |
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Definition
|
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Term
| what it he relationship between TCO2 and HCO3-? |
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Definition
| should be withing 1 or 2 units of each other. TCO2 is total CO2, which is mostly bicarb. |
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Term
|
Definition
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Term
|
Definition
|
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Term
|
Definition
| A condition leading towards an increase in blood pH |
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Term
|
Definition
| A condition leading towards a decrease in blood pH |
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Term
| Identify the blood gas parameters associated with metabolic disorders? |
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Definition
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Term
| What blood gas parameters are associated with respiratory disorders? |
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Definition
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Term
| What is compensation? What parameters move in the same or opposite direction? Why? |
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Definition
| Body's attempt to normalize blood pH. Tries to maintain the 20 HCO3 to 1 pCO2. It changes the other parameter in the same direction (increase acid = increase base) |
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Term
| what leads to respiratory acidosis? |
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Definition
| Decreased ventilation due to anesthesia, CNS disease, and severe pulmonary disease |
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Term
| What causes respiratory alkalosis? |
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Definition
| Increased ventilation from fear/pain, heat stroke, moderate pulmonary disease and iatrogenic |
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Term
| What causes metabolic acidosis? |
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Definition
| Loss/sequestration of H+ via the GI or kidney, iatrogenic and decreased K+ with dehydration |
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Term
| What causes metabolic alkalosis? |
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Definition
Titration - increased anions
secretion/loss from renal or GI |
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Term
| What is the anion gap formula? |
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Definition
| AG = (Na + K) - (HCO3 + Cl) |
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Term
| What are two unmeasured cations? |
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Definition
|
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Term
| What are 5 unmeasured anions that may be found in blood in health or disease? |
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Definition
| Phosphates, sulfates, lactates, ketones, exogenous anions, albumin and globulins |
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Term
| What specific type of acid-base disturbance is associated with an increased anion gap? What are 5 specific causes for this disturbance? |
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Definition
| metabolic titrational acidosis can be caused by endogeous anions - Uremic acids, lactic acids and ketoacids. exogenous include ethylene glycol |
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Term
| What is the most common cause of decreased anion gap? What causes a negative anion gap? |
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Definition
| Hypoalbuminemia is the most common cause of decreased anion gap, Bromide from industrial waste or potassium bromide for seizure control can cause a negative anion gap |
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Term
| What change in anion gap is more clinically significant, increase or decrease? Why? |
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Definition
| Increase of anion gap, as there are more possible pathologies attached to the process of titrational metabolic acidosis |
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Term
| What are 3 ways of determining metabolic acidosis? |
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Definition
| High anion gap, chloride increased relative to sodium, hyperkalemia |
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Term
| What is the mechanistic difference between a secretion and a titration metabolic acidosis? |
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Definition
| Titrational occurs because bicarb is consumed by acids to neutralize them. Secretional usually comes from GI/pancreatic, saliva loss and urinary loss |
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Term
| What laboratory data is used to differentiate between a titrational and secretional acidosis? |
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Definition
| High anion gap for titrational as bicarb is used to neutralize acid, increase potassium, decreased bicarb and urine pH no affect on chloride compared to sodium. No change in anion gap on secretional, decreased TCO2 and chloride increases compared to soidum |
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Term
| How does blood pH affect serum potassium levels? |
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Definition
| Increased hydrogen ions in the blood are driven into cells, which drives potassium out to keep electroneutrality. Opposite happens with increased pH (less hydrogen) |
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Term
| What chemistry data patterns for chloride indicate abnormal acid base status? |
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Definition
| Decreased chloride relative to sodium indicates metabolic alkalosis, increased chloride relative to sodium indicates metabolic acidosis |
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Term
| What does paradoxical aciduria look like on laboratory data? |
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Definition
| Alkalemia with aciduria, occurs due to dehydration and hyponatremia, hypochloridemia and hypokalemia |
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Term
| What fluid electrolyte alterations lead to paradoxical aciduria? |
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Definition
| Metabolic alkalosis with a need to reabsorb sodium. Hypochloridemia will lead to use of bicarb to retain sodium, hypokalemia will lead to loss of hydrogen ions to reabsorb sodium |
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Term
| What type of acid-base disturbances are characterized by increased anion gap without a concurrent decrease in TCO2? |
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Definition
| mixed acid base disorders, titrational acidosis with alkalosis |
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Term
| What is the initial reversible impact of hypercalcemia on renal function? What clinical signs are likely to be associated with this change? |
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Definition
| Hypercalcemia interferes with ADH activity on tubules and decreased release from pituitary, leading to polyuria. Eventually will lead to polydysia with dehydration, causing pre-renal azotemia that looks like a renal azotemia |
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Term
| Describe 3 mechanisms by which renal failure in dogs and cats may contribute to hypocalemia? |
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Definition
| Secondary to retention of phosphorous (hyperphosphatemia) and decreased vitamin D production due to decreased renal mass or suppression by phosphorous. |
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Term
| why is hypercalcemia more common with renal disease in horses than in other species? |
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Definition
| Horses do not limit GI absorption of calcium, so renal excretion has more control on blood calcium levels. Horses with renal failure do not excrete calcium if they are still eating. |
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Term
| Why is hypocalcemia more significant if an animal is alkalotic? |
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Definition
| Alkalosis/alkalemia means there are fewer hydrogen ions, increasing the protein bound portion of calcium. Alkalosis with hypocalcemia can mask the degree of reduction in ionized calcium. |
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Term
| What is the most common clinical manifestation of hypocalcemia in cows? Dogs? Why are they different? |
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Definition
| Both species most commonly are affected by milk fever. Cows show flaccid paralysis and dogs become tetanic. In cows it is a more acute drop at parturition and during lactation while in dogs it's more prolonged |
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Term
| What 2 primary endocrine diseases are associated with hypercalcemia? |
|
Definition
| Primary hyperparathyroidism - excess PTH from primary tumor and addinson's disease, lack of aldosterone |
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Term
| Why is hypomagnesemia often accompanied by hypocalcemia? |
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Definition
| Magnesium is necessary for the release of PTH, so with low magnesium, you see low calcium from decreased PTH |
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Term
| Alterations in serum phosphorus are most commonly a reflection of what renal parameter? |
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Definition
| Glomerular filtration rate |
|
|
Term
| what is the major clinical consequence of severe hypophosphatemia? At what serum concentration of phosphorus does this consequence become a high concern? |
|
Definition
| Hemolysis of red blood cells from lack of ATP to maintain red cell membranes. Concentration of less than 1 mg/dl |
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Term
| What is the role of hyperphosphatemia in the pathogenesis of secondary renal hyperparathyroidism? |
|
Definition
| Increased phosphorus levels cause ionized calcium to precipitate in soft tissues, phosphorus inhibits 1 alpha hydroxylase decreasing active vitamin D, both leading to hypocalcemia and therefore an increased release of parathyroid hormone |
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Term
| In renal failure, total body sodium is low while serum sodium concentrations are often normal. Why? |
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Definition
| While there is a renal loss of sodium, the degree of loss is often masked by dehydration |
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Term
| What is the significance of severe hyponatremia in association with renal azotemia in most species? |
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Definition
| It is likely there is a secondary renal azotemia, impaired tubules due to medullary washout with superimposed prerenal azotemia. It looks like renal failure, but treating it as such will not correct the process. |
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Term
| Large decreases in serum sodium can be typical of renal failure in which species? Why? |
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Definition
| Bovine renal failure due to greater loss of sodium as well as GI sequestration of sodium secondary to gut stasis |
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|
Term
| Why is serum potassium often a poor indicator of total body potassium? |
|
Definition
| Most potassium in the body is intracellular. |
|
|
Term
| What two mechanisms is potassium elevated in renal disease? |
|
Definition
| Obstructive disease/anuria/oliguria and hypoaldosteronism |
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|
Term
| Why is hypokalemia more significant if there is concurrent metabolic acidosis? What system is most likely clinically affected by hypokalemia? |
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Definition
| Hypokalemia with metabolic acidosis reflectes a depletion of full body stores of potassium, as the acidotic state drives hydrogen ions into cells and potassium out. |
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