Which of the following is true of nephrons?
- A. they are the functional units of the kidneys
- B. the proximal convoluted tubules allow the kidney to concentrate or dilute urine
- C. there are about a million nephrons in each kidney
- D. both a and c are correct
Correct Answer: D
Rationale: Step 1: Identify key characteristics of nephrons - functional units of kidneys, responsible for urine formation.
Step 2: Confirm accuracy of statements - A: Nephrons are functional units. C: About a million nephrons in each kidney.
Step 3: Combine statements - A + C = D, confirming both are correct.
Step 4: Justify choice D - correct because nephrons are indeed functional units and there are approximately a million in each kidney.
Summary: B is incorrect as the proximal convoluted tubules are not solely responsible for urine concentration/dilution. Choice D is correct as it combines the accurate statements from A and C.
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Spironolactone can be usefully combined with the following diuretics except: *
- A. Amiloride
- B. Chlorthalidone
- C. Furosemide
- D. Hydrochlorothiazide
Correct Answer: D
Rationale: Spironolactone is a potassium-sparing diuretic, so combining it with another potassium-sparing diuretic like amiloride can lead to hyperkalemia. Chlorthalidone, a thiazide-like diuretic, can be synergistic with spironolactone. Furosemide, a loop diuretic, can counteract the potassium-sparing effects of spironolactone. Hydrochlorothiazide, a thiazide diuretic, can also lead to hypokalemia when combined with spironolactone. Therefore, the correct answer is D, as combining spironolactone with hydrochlorothiazide may increase the risk of potassium imbalance.
Which antibiotic course is inappropriate for clinical scenario?
- A. Acute simple cystitis - trimethoprim for 3 days in otherwise well young women.
- B. Acute uncomplicated pyelonephritis - gentamycin + amoxicillin IV initially followed by 7 days of Augmentin orally.
- C. Pregnancy associated cystitis - nitrofurantoin 5 mg QID for 14 days.
- D. Acute simple cystitis in male patients - Augmentin or trimethoprim for 14 days.
Correct Answer: B
Rationale: The correct answer is B because the antibiotic regimen for acute uncomplicated pyelonephritis should not include gentamycin due to its potential toxicity and nephrotoxicity. The initial use of IV gentamycin is not recommended for uncomplicated pyelonephritis. The combination of gentamycin and amoxicillin is not the standard treatment for this condition. Gentamycin should be reserved for more serious infections. The choice of Augmentin for 7 days orally is also not the standard of care for pyelonephritis. The other choices (A, C, D) are appropriate antibiotic regimens for the corresponding clinical scenarios.
Which of the following would be examples of foods selected to lower the pH of urine?
- A. Milk
- B. Tea
- C. Apples
- D. Meat
Correct Answer: C
Rationale: The correct answer is C: Apples. Apples are acidic in nature, which can help lower the pH of urine. Consuming acidic foods can make the urine more acidic. Milk is alkaline, so it would raise the pH of urine. Tea can vary in acidity, but generally it is not chosen to lower urine pH. Meat is also not acidic and would not contribute to lowering urine pH. So, apples are the most suitable choice for lowering urine pH among the options provided.
Due to its potential for severe hepatotoxicity, Nevirapine should NOT be initiated in:
- A. Women with CD4 cell counts >150 cells/mm3 or in men with CD4 cell count >400 cells/mm3
- B. Women with CD4 cell counts >250 cells/mm3 or in men with CD4 cell count >400 cells/mm3
- C. Women with CD4 cell counts >250 cells/mm3 or in men with CD4 cell count >500 cells/mm3
- D. Women with CD4 cell counts >250 cells/mm3 or in men with CD4 cell count >450 cells/mm3
Correct Answer: B
Rationale: The correct answer is B. Nevirapine has a higher risk of severe hepatotoxicity in patients with higher CD4 cell counts. Choice B specifies a lower threshold for CD4 cell counts in women compared to men, which aligns with the caution needed for initiating Nevirapine. Choices A, C, and D have higher CD4 cell count thresholds for both women and men, which would increase the risk of hepatotoxicity if Nevirapine is initiated in those patients. Therefore, Choice B is the most appropriate option to minimize the risk of hepatotoxicity when initiating Nevirapine.
"Red man syndrome "has been associated with rapid intravenous injection of * which of the following antibiotic?
- A. Vancomycin
- B. Clindamycin
- C. Cefoperazone
- D. Piperacillin
Correct Answer: A
Rationale: The correct answer is A: Vancomycin. Red man syndrome is a hypersensitivity reaction caused by rapid infusion of vancomycin. Vancomycin infusion releases histamine, leading to flushing, rash, and hypotension. Clindamycin (B), Cefoperazone (C), and Piperacillin (D) are not associated with red man syndrome. Clindamycin can cause pseudomembranous colitis, Cefoperazone can cause bleeding disorders, and Piperacillin can cause hypersensitivity reactions, but not red man syndrome.