What is the role of diuretics in the management of kidney diseases?

Diuretics and Kidney Diseases: 20 MCQs

Loop diuretics are the first-line agents for managing edema in glomerular kidney diseases, with twice daily dosing preferred over once daily dosing to achieve optimal diuretic effect. 1

Here are 20 multiple-choice questions with answers on diuretics and kidney diseases:

Questions on Diuretic Pharmacology and Mechanisms

1. Which of the following statements about loop diuretics is TRUE? a) They act primarily on the distal convoluted tubule b) They inhibit the Na+/K+/2Cl- cotransporter in the ascending limb of loop of Henle c) They have a longer duration of action than thiazide diuretics d) They are ineffective in patients with GFR <30 ml/min/1.73 m²

   Answer: b) They inhibit the Na+/K+/2Cl- cotransporter in the ascending limb of loop of Henle 1

2. Which of the following loop diuretics has the longest duration of action? a) Furosemide b) Bumetanide c) Torsemide d) Ethacrynic acid

   Answer: c) Torsemide 1

3. The primary site of action for thiazide diuretics is: a) Proximal convoluted tubule b) Loop of Henle c) Distal convoluted tubule d) Collecting duct

   Answer: c) Distal convoluted tubule 1

4. Which mechanism explains the reduced efficacy of diuretics in nephrotic syndrome? a) Decreased renal blood flow b) Binding of diuretics to proteins in tubular fluid c) Increased glomerular filtration rate d) Decreased sodium reabsorption in proximal tubule

   Answer: b) Binding of diuretics to proteins in tubular fluid 2

5. In patients with chronic kidney disease, the pharmacokinetics of diuretics are altered by: a) Increased tubular secretion b) Decreased protein binding in plasma c) Reduced delivery to site of action due to decreased GFR d) Increased hepatic metabolism

   Answer: c) Reduced delivery to site of action due to decreased GFR 3, 4

Questions on Clinical Use of Diuretics in Kidney Disease

1. Which diuretic is most appropriate as first-line therapy for edema management in glomerular disease? a) Thiazide diuretic b) Loop diuretic c) Potassium-sparing diuretic d) Carbonic anhydrase inhibitor

   Answer: b) Loop diuretic 1

2. In a patient with nephrotic syndrome and resistant edema, which combination therapy is most effective? a) Two different loop diuretics b) Loop diuretic plus thiazide diuretic c) Thiazide diuretic plus potassium-sparing diuretic d) Loop diuretic plus carbonic anhydrase inhibitor

   Answer: b) Loop diuretic plus thiazide diuretic 1, 5

3. At what level of GFR do thiazide diuretics generally become ineffective as monotherapy? a) <60 ml/min/1.73 m² b) <45 ml/min/1.73 m² c) <30 ml/min/1.73 m² d) <15 ml/min/1.73 m²

   Answer: c) <30 ml/min/1.73 m² 2, 4

4. Which strategy is recommended for diuretic-resistant edema in nephrotic syndrome? a) Increasing the dose of loop diuretic indefinitely b) Adding a thiazide diuretic to a loop diuretic c) Switching to a potassium-sparing diuretic d) Discontinuing diuretics and using dietary sodium restriction alone

   Answer: b) Adding a thiazide diuretic to a loop diuretic 1

5. In patients with chronic kidney disease, which dosing strategy for loop diuretics is most appropriate? a) Once daily dosing at a fixed dose b) Twice daily dosing with dose titration based on response c) Continuous infusion at all times d) As-needed dosing based on daily weight

   Answer: b) Twice daily dosing with dose titration based on response 1, 3

Questions on Monitoring and Adverse Effects

1. Which electrolyte abnormality is most commonly associated with loop diuretic therapy? a) Hyperkalemia b) Hypokalemia c) Hypernatremia d) Hypermagnesemia

   Answer: b) Hypokalemia 1

2. Which of the following is NOT a common adverse effect of thiazide diuretics? a) Hyponatremia b) Hyperkalemia c) Hyperuricemia d) Hypercalcemia

   Answer: b) Hyperkalemia 1, 6

3. When using spironolactone in a patient with chronic kidney disease, which parameter requires the most careful monitoring? a) Serum sodium b) Serum potassium c) Serum magnesium d) Serum calcium

   Answer: b) Serum potassium 1, 7

4. Which of the following is a contraindication to using potassium-sparing diuretics in advanced kidney disease? a) Hypotension b) Hyponatremia c) Risk of hyperkalemia d) Metabolic acidosis

   Answer: c) Risk of hyperkalemia 2, 7

5. The recommended timing for monitoring serum potassium after initiating spironolactone is: a) Within 24 hours b) Within 1 week c) Within 2 weeks d) Within 1 month

   Answer: b) Within 1 week 7

Questions on Special Clinical Scenarios

1. In a patient with nephrotic syndrome who is not responding to a high-dose loop diuretic, which of the following is the most appropriate next step? a) Switch to a different loop diuretic b) Add a thiazide diuretic c) Add spironolactone d) Discontinue diuretic therapy and initiate ultrafiltration

   Answer: b) Add a thiazide diuretic 1

2. Which diuretic combination may be particularly useful for treating metabolic alkalosis associated with loop diuretic therapy? a) Loop diuretic + thiazide diuretic b) Loop diuretic + acetazolamide c) Loop diuretic + spironolactone d) Thiazide diuretic + amiloride

   Answer: b) Loop diuretic + acetazolamide 1

3. In patients with glomerular disease and hypertension, which medication should be used as first-line therapy? a) Loop diuretic b) Thiazide diuretic c) ACE inhibitor or ARB d) Beta-blocker

   Answer: c) ACE inhibitor or ARB 1

4. When using loop diuretics in combination with ACE inhibitors in a patient with nephrotic syndrome, which of the following is a major concern? a) Hyperkalemia b) Acute kidney injury c) Metabolic acidosis d) Hypernatremia

   Answer: b) Acute kidney injury 1

5. Which statement about diuretic resistance in kidney disease is TRUE? a) It is primarily caused by decreased renal blood flow b) It can be overcome by continuous infusion but not by oral dosing c) It may result from increased sodium reabsorption in nephron segments not affected by the diuretic d) It cannot be overcome by combination diuretic therapy

   Answer: c) It may result from increased sodium reabsorption in nephron segments not affected by the diuretic 2, 5

Key Points About Diuretics in Kidney Diseases

• Loop diuretics are first-line agents for edema management in glomerular diseases, with furosemide being most commonly used 1
• Twice daily dosing of loop diuretics is preferred over once daily dosing for optimal effect 1
• In diuretic resistance, combination therapy with different classes (loop + thiazide) is more effective than increasing the dose of a single agent 1, 5
• Dietary sodium restriction (<2.0 g/d) should accompany diuretic therapy 1
• Common adverse effects include electrolyte abnormalities (hypokalemia, hyponatremia) and worsening renal function 1, 7
• Potassium-sparing diuretics must be used cautiously in kidney disease due to hyperkalemia risk 7, 2
• Thiazide diuretics lose effectiveness as monotherapy when GFR falls below 30 ml/min/1.73 m² 2, 4
• Diuretic dosing must be increased in kidney disease to overcome reduced drug delivery to site of action 3, 4