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33 Cards in this Set
- Front
- Back
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Which of the following crystals is most strongly birefringent?
A. calcium pyrophosphate B. monosodium urate C. hydroxyapatite D. corticosteroid E. cholesterol |
B. monosodium urate.
Monosodium urate is the most strongly birefringent crystal seen in synovial fluids. Urate crystals are needle-shaped with negative birefringence and rapid extinction (goes away quickly with a small change in the angle of the compensator) under polarization. Negatively birefringent crystals are yellow when parallel to the long axis of the compensator and blue when perpendicular. Positive birefringence is the opposite. Urate crystals are needle-shaped and a needle looks like a minus sign (negative birefringence). Also, yellow and parallel have double “l's.” See the text for an additional helpful mnemonic. QCCP2, Synovial fluid microscopy |
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Which of the following criteria is considered positive for a diagnostic peritoneal lavage?
A. >1 mL gross blood B. RBCs >1000/mL C. WBCs >5/mL D. DPL fluid in Foley catheter E. mesothelial cells >100/mL |
D. DPL fluid in Foley catheter.
More than 15mL of blood, 100,000 red blood cells/mL, 500 white blood cells/mL are considered positive findings. Finding lavage fluid in the places other than the peritoneum, such as in the bladder or pleural space, is also considered a positive finding. Finally, if any bacteria is present on gram stain, that is considered a positive finding. QCCP2, Peritoneal fluid microscopym |
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Which of the following tests are characteristically elevated in a pleural effusion associated with rheumatoid arthritis?
A. pH B. glucose C. LDH D. A & B E. A, B, C |
C. LDH.
Typically, the pH and glucose are decreased, while the LDH and rheumatoid factor levels are elevated. QCCP2, Collagen vascular diseasesè"`˜L |
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Which feature most specifically distinguishes a parapneumonic pleural effusion from an empyema?
A. the presence of neutrophils B. specific gravity >1.010 C. LDH levels D. the absence of bacteria E. acidic pH |
D. the absence of bacteria.
An empyema is usually the result of a secondarily-infected parapneumonic effusion. Neutrophils can be present in a parapneumonic effusion, but not to the levels seen in an empyema. The pH of an empyema tends to be acidic. The most important differentiation factor is the presence or absence of bacteria. QCCP2, Parapneumonic effusion=0m |
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Which of the following pleural fluid test results confirms your clinical suspicion of an exudate?
A. pleural fluid to serum protein ratio >0.3 B. pleural fluid to serum LDH ratio >0.3 C. pleural fluid LDH >200, or 2/3 the upper limit of serum LDH D. specific gravity >1.006 E. pleural fluid protein >1 g/L |
C. pleural fluid LDH >200, or 2/3 the upper limit of serum LDH.
The Light criteria are the most commonly used guidelines for the determination of whether an effusion is an exudate or transudate. Once the fluid is categorized, then potential etiologies can be explored. A protein ratio >0.5, an LDH ratio >0.6, and LDH >200 are all suggestive of an exudate. Some other ancillary tests can also be performed to help with determination, such as specific gravity (>1.01 implies exudate, also protein >3g/dL, cholesterol >45 mg/dL, and a bilirubin ratio >0.6). QCCP2, Pleural fluid |
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At what time of the day are cortisol levels typically highest and lowest, respectively?
A. midnight, 8 a.m. B. 8 a.m., midnight C. 6 a.m., 6 p.m. D. 6 p.m., 6 a.m. E. there are no usual peaks or troughs |
B. 8 a.m., midnight.
The easiest way to remember when peaks and troughs occur is to think about when babies are usually born (or at least when labor begins). Usually in the small hours of the morning, corresponding to the a.m. cortisol spike. And like most people, at the end of the day, you are tired and so is your pituitary, where there is a significant trough at midnight. This is also why an elevated midnight serum cortisol is suggestive of Cushing syndrome. This also explains why the 24-hour urine cortisol is a superior test of overall cortisol levels - it negates diurnal variation. QCCP2, Adrenal cortex tests |
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Which of the following is the best test for confirming Cushing disease?
A. serum TSH B. 24-hour urine cortisol C. low dose dexamethasone suppression test D. high dose dexamethasone suppression test E. metyrapone stimulation test |
D. high dose dexamethasone suppression test.
While urine cortisol and low dose DST would be positive in cases of Cushing disease, they cannot distinguish Cushing syndrome (elevated serum cortisol) from Cushing disease (elevated serum cortisol due to a pituitary adenoma). The DST suppresses ACTH in the pituitary and CRH in the hypothalamus, and therefore will discover if the patient has hypercortisolism due to upstream causes. QCCP2, Adrenal cortex |
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What is the best time to collect samples of salivary cortisol to be used as a screening tool for Cushing syndrome?
A. early morning B. mid day C. early evening D. late-night E. the collection time is immaterial |
D. late-night.
Remember that typically, the most significant trough of cortisol occurs around midnight (“you and your pituitary are tired”). It would make sense that the best time to assay elevated cortisol is when the cortisol should be at its lowest. The salivary cortisol is an excellent screening tool with very high sensitivity and specificity for elevated free cortisol. QCCP2, Adrenal cortex |
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What's the most common non-iatrogenic cause of Cushing syndrome?
A. Cushing disease B. ectopic ACTH production by tumor C. iatrogenic steroid administration D. hypothalamic dysfunction E. adrenocortical carcinoma |
A. Cushing disease.
To be honest, iatrogenic Cushing syndrome should be in a separate category of what the “non-iatrogenic causes.” Administration of steroids is probably the most common cause of Cushing syndrome. Outside of those cases, the most common organic cause of Cushing syndrome is cortisol overproduction due to pituitary adenoma and increased ACTH. QCCP2, Cushing syndrome |
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Which of the following signs/symptoms is associated with Addison disease?
A. hypokalemia B. hypernatremia C. hyperglycemia D. hyperpigmentation E. osteoporosis |
D. hyperpigmentation.
Like with hypercortisolism, hypocortisolism can be divided into an eponymous general “syndrome” and specific cause of the syndrome, “disease.” Addison syndrome is defined as hypocortisolism, while Addison disease is defined as hypocortisolism due to primary adrenal insufficiency. When cortisol drops, the pituitary produces more ACTH, but it is stimulated by the CRH from the hypothalamus. CRH is secreted in a prohormone (POMC) that also encodes an opiate and melanocyte-stimulating hormone (MSH), which accounts for the hyperpigmentation. QCCP2, Addison syndrome and ACTH |
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What's the most common cause of Conn syndrome?
A. pituitary adenoma B. adrenal adenoma C. juxtaglomerular cell tumor of the kidney D. renal artery stenosis E. ectopic hormone production by tumor |
B. adrenal adenoma.
Conn syndrome refers to the constellation of symptoms secondary to hyperaldosteronism (hypernatremia, hypokalemia, hypertension). While renal artery stenosis (bilateral, usually) and juxtaglomerular tumors can cause reactive (secondary) hyperaldosteronism, the most common cause of hyperaldosteronism is primary overproduction from an adrenal adenoma. Extra credit - which layer of the adrenal cortex is responsible for the production of aldosterone? The answer is zona glomerulosa. QCCP2, Conn syndrome |
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What is the most common cause of congenital adrenal hyperplasia?
A. 11-hydroxylase deficiency B. 17-hydroxylase deficiency C. 21-hydroxylase deficiency D. growth hormone deficiency E. 17-hydroxyprogesterone deficiency |
C. 21-hydroxylase deficiency.
Deficiency of the enzyme 21-hydroxylase accounts for the majority of cases of CAH. The gene encoding 21-hydroxylase is in the MHC complex on 6p21.3 and mutations are typically due to gene conversion by recombination between an active gene and a colocated pseudogene. QCCP2, Congenital adrenal hyperplasia |
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What is the most common cause of salt-wasting congenital adrenal hyperplasia?
A. 11-hydroxylase deficiency B. 17-hydroxylase deficiency C. 21-hydroxylase deficiency D. growth hormone deficiency E. 17-hydroxyprogesterone deficiency |
C. 21-hydroxylase deficiency.
As detailed above, 21-hydroxylase is the overall most common cause of CAH, but also the most common cause of the salt-wasting form. Typically, patients with salt- wasting have more severe disease and hence earlier presentation overall, with girls presenting earlier than boys due to the high incidence of ambiguous genitalia. Salt-losing is due to the decreased aldosterone, which results in decreased reabsorption of sodium from the urine and hence hyponatremia. QCCP2, Congenital adrenal hyperplasia |
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All of the following pituitary hormones are produced by basophilic cells, except:
A. FSH B. TSH C. LH D. GH E. ACTH |
D. GH.
The majority of hormones in the anterior pituitary are produced by basophilic cells. Remember, the differentiation of acidophils from basophils is made with a supravitalstain, such as acridine orange. The only anterior pituitary hormones produced by acidophils are prolactin and growth hormone. The remaining hormones, luteinizing hormone, follicle-stimulating hormone, thyroid-stimulating hormone, and adrenocorticotrophic hormone are produced by basophils. The mnemonic “TOGA FLAP” help with recall of the hormones of the pituitary: TSH, oxytocin, GH, ACTH, FSH, LH, ADH, prolactin. Oxytocin and ADH are produced by the posterior pituitary. QCCP2, Pituitary |
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What's the most commonly secreted hormone due to a pituitary tumor?
A. ACTH B. prolactin C. GH D. LSH E. TSH |
B. prolactin. The most common pituitary secretory tumor is the prolactinoma and it is usually very small. Interestingly, due to its unique means of control (dopamine-mediatedrepression), prolactin is unlikely to be hyposecreted like the other pituitary hormones with a stalk-compressive lesion.
QCCP2, Pituitary |
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How is an insulin tolerance test used to measure growth hormone?
A. insulin-like growth factor is measured after insulin administration as a growth hormone surrogateB. insulin creates hypoglycemia, stimulating GH production C. insulin causes ion shifts which are sensed in the pituitary and lead to GH release D. insulin inhibits growth hormone uptake leading to increased serum GH levels E. insulin directly stimulates the release of GHRH from the hypothalamus |
B. insulin creates hypoglycemia, stimulating GH production.
The insulin intolerance test is used in cases of suspected growth hormone deficiency. Similarly, clonidine, arginine, or exercise can be used to provoke growth hormoneexpression. Insulin administration results in hypoglycemia, which causes a reflexive stimulation of growth hormone secretion. Insufficient growth hormone levels are indicative of deficiency. In cases of growth hormone excess, IGF-1 can be measured - increased levels are indicative of excess. QCCP2, Growth hormone |
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How does administration of a GnRH agonist inhibit FSH and LH?
A. by acting as a synthetic nonstimulatory FSH/LH mimic B. by downregulating FSH or LH receptors C. by disrupting FSH/LH-mediated cell signaling D. by inhibiting production of FSH and LH E. by increasing synthesis of an inhibitory substance |
D. by inhibiting production of FSH and LH.
Leuprolide and goserelin are both GnRH agonists used as therapy against hormone-sensitive malignancies, such as prostate cancer. A GnRH agonist works as an initialstimulant of FSH/LH production, but then it begins to be inhibitory, decreasing the amounts of FSH and LH. LH normally functions to increase androgen production; therefore inhibition of LH leads to inhibition of testosterone. QCCP2, FSH and LH |
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Which of the following profiles is most consistent with diabetes insipidus?
A. hypernatremia with a low urine osmolarity B. hypernatremia with a high urine osmolarity C. hyponatremia with a low urine osmolarity D. hyponatremia with a high urine osmolarity E. hyperkalemia with unchanged urine osmolarity |
A. hypernatremia with low urine osmolarity.
A simple way to think of hypernatremia and hyponatremia is as derangements in body water rather than sodium. That is, hypernatremia is having too little water; hyponatremia is having too much. Then remember that diabetes insipidus is the result of inadequate anti-diuretic hormone - either because there in not enough made (central DI) or because the kidneys don't respond (nephrogenic DI). Anti-diuretic hormone helps us to conserve water by activating water channels (aquaporins) in thecollecting duct and “taking back” water from urine. Without ADH, we would get rid of excess water in the urine, leading to the characteristic hypernatremia with low urine osmolarity. SIADH would be expected to have the opposite presentation. QCCP2, ADH |
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Which of the following samples is the most useful in diagnosing hyperglycemia in a postmortem situation?A. arterial serum
B. whole arterial blood C. venous blood D. intravesicle urine E. vitreous humor |
E. vitreous humor.
Okay, this is one of those times that you can collect vitreous humor. Blood levels of glucose tend to rise post-mortem; vitreous levels tend to drop. Therefore, an elevated post-mortem vitreous glucose is suggestive of hyperglycemia. However, since vitreous glucose levels drop post-mortem it would be inappropriate to diagnosehypoglycemia from a vitreous sample. QCCP2, Glucose |
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Which one of the following vitreous chemistry patterns is most consistent with decomposition?
A. increased sodium, increased chloride, increased potassium B. decreased sodium, decreased chloride, increased potassium C. decreased sodium, increased chloride, increased potassium D. increased sodium, increased chloride, decreased potassium E. decreased sodium, decreased chloride, decreased potassium |
B. decreased sodium, decreased chloride, increased potassium. If you remember one thing about vitreous chemistry, remember that elevated potassium (>15 mEq/L) is indicative of decomposition. The vitreous potassium level risesin a consistent linear fashion after death and provides a fairly standard indication of the proximate interval post-mortem. If you want to remember two things about vitreous humor chemistry, see the previous question.
QCCP2, Sodium and chloride, potassium |
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Which of the following tests provides the most accurate evidence for death caused by anaphylaxis?
A. total serum immunoglobulin B. total serum IgE C. serum alpha-tryptase D. serum beta-tryptase E. peripheral eosinophil count |
D. serum beta-tryptase. I know that the answer to this question is not in the text, but it is an important issue. Serum tryptase is one of the most reliable means of diagnosing anaphylaxis,
specifically, beta-tryptase, which is released during mast cell and eosinophil activation. Alpha-tryptase is present in the serum and its levels don't change much withanaphylaxis. QCCP2, Tryptase and post-mortem diagnosis of anaphylaxis |
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Which of the following is the best advantage of the Clinitest method v. the dipstick method for detecting glucose in the urine?
A. ability to detect other “reducing substances” B. superior glucose detection sensitivity C. increased specificity D. increased positive predictive value E. cost |
A. ability to detect other “reducing substances.”
Some of the above choices may or may not be true, depending on the circumstances. However, the ability to measure other reducing substances, such as galactose, isthe clear advantage of Clinitest. QCCP2, Urine glucose |
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Which of the following unique patterns is most consistent with free light chains (Bence-Jones proteins) in urine?
A. precipitate at 40°, then redissolve at 60° B. precipitate at 100°, then cool to redissolve at 60° C. heat to precipitate at 40°, redissolve at 100°, then cool to reprecipitate at 60° and redissolve at 40° D. heat to precipitate at 100°, redissolve with cooling to 60°, reprecipitate at 40° E. none of the above are accurate |
C. heat to precipitate at 40°, redissolve at 100°, then cool to reprecipitate at 60° and redissolve at 40°.
We have another “longest-answer-is-correct” question. Bence-Jones proteins have the unique property that, when heated, they will precipitate when the temperaturereaches 40-60°C. Continued heating to 100°C will make the proteins redissolve. If then allowed to cool, the proteins will reprecipitate when the temperature reaches 60°C and, finally, again redissolve at 40°C. Nowadays, a urine protein electrophoresis is done more often to answer the same question. QCCP2, Urine protein |
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Which of the following can be distinguished from hemoglobinuria on a urine dipstick via urine microscopy?
A. myoglobinuria B. hematuria C. proteinuria D. bilirubinemia E. cholesterol |
B. hematuria.
The most common hemoglobin confounder on urine dipstick is myoglobin. However, myoglobinuria and hemoglobinuria cannot be differentiated by microscopy. Red bloodcells will also give a positive result on urine dipstick and can be differentiated on urine microscopy. QCCP2, Urine hemoglobin |
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Which of the following common causes of urinary tract infections will give a positive nitrite test?
A. Enterococcus faecalis B. Neisseria gonorrheae C. Escherichia coli D. Mycobacterium tuberculosis E. Candida albicans |
C. E.
While nitrate may be present in normal urine, nitrite is usually only due to presence of bacteria that are capable of reducing nitrate to nitrite. Also, urine must beincubated with the organism for a sufficient length of time in order for the nitrite to form. In addition, the patient's diet must include sufficient nitrate precursors.QCCP2, Urine nitrite |
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All of the following are causes of increased urine specific gravity, except:
A. diabetes mellitus B. diabetes insipidus C. congestive heart failure D. proteinuria E. syndrome of inappropriate antidiuretic hormone |
B. diabetes insipidus.
Increased specific gravity is consistent with increased urine concentration either due to less solvent (water) or more solute (protein, glucose, etc). In the case ofdiabetes insipidus there is a lack of water conservation leading to profound diuresis of very dilute urine. QCCP2, Urine specific gravity |
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What's the composition of the most common kidney stone?
A. calcium oxalate B. calcium phosphate C. magnesium ammonium phosphate D. urate E. cystine |
A. calcium oxalate.
The order of choices is roughly the incidence from most common to less common causes of nephrolithiasis. Increased urine calcium and oxalate, along with decreased urine volume and citrate, promote the production of calcium oxalate stones. Calcium phosphate stones are also promoted by hypercalciuria, frequently in the face of hypercalcemia. MAP stones are promoted by urea-splitting organisms such as Proteus mirabilis. Increased uric acid promotes urate stones, and cystine stones are almostexclusively seen in the setting of cystinuria, an autosomal recessive defect in amino acid transport. QCCP2, Nephrolithiasis |
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Which of the following urine microscopy findings is most consistent with glomerular bleeding?
A. uniform RBC morphology B. red blood cell casts C. uniform hemoglobin concentration D. lack of erythrophagocytosis E. none of the above |
B. red blood cell casts.
Damage to the glomerulus usually results in bad-looking sediment including polymorphous red blood cells, red cell casts, and erythrophagocytosis. Non-glomerularbleeding results in a more refined sediment with uniform red blood cells, no casts nor erythrophagocytosis. QCCP2, Casts |
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Which of the following types of casts is most specific for glomerulonephritis?
A. hyaline casts B. red blood cell casts C. white blood cell casts D. tubular casts E. waxy casts |
B. red blood cell casts.
Both hyaline and waxy casts are relatively non-specific and can be seen with almost any type of renal injury, RBC/WBC and tubular casts are more specific. RBC castsare usually indicative of renal glomerular damage, such as that due to glomerulonephritis. WBC casts are seen most often with tubulointerstitial disease, such as pyelonephritis. Tubular casts are made of shed necrotic renal tubular cells and are indicative of acute tubular necrosis. QCCP2, Casts |
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All of the following modalities can be used to diagnose cerebrospinal fluid leak in cases of rhinorrhea or otorrhea of unknown etiology, except:
A. glucose measurement B. fluid protein electrophoresis C. specific gravity D. asialated transferrin measurement E. protein measurement |
C. specific gravity.
Measuring the protein or glucose concentration of the fluid is a very nonspecific test. One is looking for the characteristic concentrations of each analyte (~60% of serumlevels). Protein electrophoresis and measurement of asialated transferrin are more specific. CSF has a characteristic “twin transferrin” peak due to the presence of asialated transferring that is not seen in serum. In addition, CSF has a prominent pre-albumin band. QCCP2, CSF |
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In addition to the presence of oligoclonal bands, which of the following findings is most supportive of a diagnosis of multiple sclerosis?
A. increased serum albumin B. intrathecal IgG synthesis C. increased CSF albumin D. intrathecal IgA synthesis E. CSF glutamine |
B. intrathecal IgG synthesis.
Oligoclonal bands are one of the most sensitive tests for detecting MS (in concert with clinical and radiological findings). In addition to the presence of oligoclonal bands,intrathecal IgG synthesis demonstrates activity and is suggestive of MS. Intrathecal IgA synthesis is seen most commonly with cerebral adrenoleukodystrophy, while glutamine in the CSF is associated with hepatic encephalopathy. QCCP2, CSF |
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Which of the following cell types is seen more often in normal neonatal CSF compared to adult CSF?
A. lymphocytes B. monocytes C. neutrophils D. ependymal cells E. eosinophils |
B. monocytes.
Overall there should be very few cells present in the CSF. Neonates tend to have more monocytes and fewer lymphocytes than adults. When WBCs are present in theCSF, the differential for a normal neonate is different than that of a normal adult. Higher numbers of leukocytes are tolerated in the neonatal CSF. QCCP2, IVL CSF differential counts, T1.38 |
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Which of the following causes of meningitis is associated with a normal CSF glucose?
A. Neisseria meningitidis B. Mycobacterium tuberculosis C. JC virus D. Escherichia coli E. herpes simplex virus |
C. JC virus.
Most bacterial, mycobacterial, and fungal causes of meningitis are associated with decreased CSF glucose, while most viral meningitides are associated with normal CSFglucose. However, HSV causes of meningoencephalitis are actually also associated with decreased CSF glucose. QCCP2, CSF differential counts in meningitis, T1.39 |
