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Azotemia and UrinaryAbnormalities
(Chapter 45)
Multiple Choice
1. The most widely used marker for glomerular filtration rate determination:a. Urea c. Inulinb. Creatinine d. Creatine
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GFR
• Serum creatinine is the most widely used marker for GFR
• GFR is related directly to the urine creatinine excretion and inversely to the serum creatinine (UCr/PCr)
• Creatinine clearance - defined time period (usually 24 h) and is expressed in mL/min
• In general, patients do not develop symptomatic uremia until renal insufficiency is usually quite severe (GFR < 15 mL/min)
GFR
• Urea clearance may significantly underestimate GFR because of tubule urea reabsorption.
• Creatinine is useful for estimating GFR because it is a small, freely filtered solute.
• More accurate determinations of GFR are available using inulin clearance or radionuclide-labeled markers such as 125I-iothalamate or EDTA.
Multiple Choice
2. Calculate for the estimated GFR of a 75 y/o female weighing 75kg with serum creatinine of 5.4 mg/dl using the Cockroft-Gault formula:a. 10 c. 11b. 13 d. 14
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GFR
• Cockroft-Gault formula:
• MDRD (modification of diet in renal disease):
Multiple Choice
3. In patients with bilateral renal artery stenosis, the drug to be avoided is:a. Metoprolol c. Nifedipineb. Clonidine d. Enalapril
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Prerenal FailureNSAIDS
ACE Inhibitors
Prerenal Failure
• Patients with bilateral renal artery stenosis (or stenosis in a solitary kidney) are dependent upon efferent arteriolar vasoconstriction for maintenance of glomerular filtration pressure and are particularly susceptible to precipitous decline in GFR when given ACE inhibitors.
Multiple Choice
4. The finding of eosinophils in the urine, optimally observed by using a Hansel stain, is suggestive of:a. Allergic interstitial nephritis
b. Atheroembolic renal diseasec. Both d. Neither
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Intrinsic Renal Disease
• The finding of eosinophils in the urine is suggestive of allergic interstitial nephritis or atheroembolic renal disease and is optimally observed by using a Hansel stain.
• The absence of eosinophiluria, however, does not exclude these possible etiologies.
• Atheroembolic renal failure can occur spontaneously but is most often associated with recent aortic instrumentation. The emboli are cholesterol-rich and lodge in medium and small renal arteries, leading to an eosinophil-rich inflammatory reaction.
Multiple Choice
5. Oliguria refers to a 24-h urine output of:a. <500 mL c. <300 mLb. <400 mL d. <50 mL
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Oliguria and Anuria
• Oliguria refers to a 24-h urine output of <500 mL
• Anuria is the complete absence of urine formation (<50 mL).
• Nonoliguria refers to urine output >500 mL/d in patients with acute or chronic azotemia
• polyuria (>3 L/d)
Multiple Choice
6. The evaluation of proteinuria is typically initiated after detection of urinary protein by a. Dipstick examinationb. 24h urinary protein excretionc. Spot morning protein/creatinine ratio
(mg/g)d. Urine protein electrophoresis (UPEP)
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Proteinuria
• The evaluation of proteinuria is typically initiated after detection of proteinuria by dipstick examination.
• Detects mostly albumin and gives false-positive results when pH > 7.0 and the urine is very concentrated or contaminated w/ blood
• Normal individuals excrete <150 mg/d of total protein and <30 mg/d of albumin.
Multiple Choice
7. An early marker of glomerular disease that has been shown to predict glomerular injury in early diabetic nephropathy is microalbuminuria of:a. <20 mg/d c. <30 mg/db. <25 mg/d d. 30-300mg/d
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Multiple Choice
8. Presence of this protein by urine protein electrophersis (UPEP) is due to plasma cell dyscrasias:a. Albumin
b. Kappa or lambda light chains c. Tamm-Horsfall d. β2-microglobulin
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Multiple Choice
9. Hematuria is defined as ___ RBCs per high-power field (HPF) and can be detected by dipstick.a. 2-5 c. 4-5b. 3-5 d. >5
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Multiple Choice
10. To distinguish a solute diuresis from a water diuresis and to determine if the diuresis is appropriate for the clinical circumstances, this laboratory examination is measured/done:a. Plasma osmolality
b. ADH level c. Urine osmolality d. Water deprivation test Page
274
Multiple Choice
11. The following are causes of water diuresis, EXCEPT:
a. Diabetes mellitusb. Diabetes insipidus, centralc. Diabetes insipidus, nephrogenic d. Primary polydipsia
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Modified True or False
12. Laboratory findings in acute tubular necrosis:a. BUN/PCr ratio >20:1 F
b. Urine osmolality >500mosml/L H2O F
c. Urine sodium (UNa) >40 meq/L T
d. FENa <1% F
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Acute Renal Failure
Modified True or False
13. Persistent or significant hematuria mean/s:a. >three RBCs/HPF on three urinalyses T b. a single urinalysis with >100 RBCs Tc. gross hematuria Td. 2-3 RBCs/HPF F
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Modified True or False
14. The following are causes of diabetes insipidus central (vasopressin-sensitive):
a. Sheehan’s syndrome Tb. Empty sella Tc. Guillain-Barre syndrome Td. Supra or intrasellar tumor T
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Modified True or False
15. The following are causes of diabetes insipidus nephrogenic (vasopressin-insensitive):
a. Sjogren’s syndrome Tb. Multiple myeloma Tc. Amyloidosis Td. Hypercalcemia T
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