Chronic Kidney Disease Management - USMLE Step 3

1. A 72-year-old man with CKD stage G4 (eGFR 26 mL/min/1.73m²), heart failure with reduced ejection fraction, and hypertension is seen for a routine clinic visit. His medications include lisinopril, carvedilol, and furosemide. A routine lab check reveals a serum potassium of 5.9 mEq/L. He is asymptomatic, and his ECG shows no acute changes. In addition to dietary counseling, what is the most appropriate long-term management strategy?
   Answer: Add a potassium-binding agent such as patiromer. This patient has chronic, asymptomatic hyperkalemia, likely related to his CKD and use of an ACE inhibitor (lisinopril). Discontinuing lisinopril would be detrimental to his heart failure management. The best strategy is to add a medication that manages chronic hyperkalemia, such as a potassium binder (patiromer or sodium zirconium cyclosilicate). This allows for the continuation of essential RAAS inhibitor therapy. Acute treatments like calcium gluconate are not indicated as there are no ECG changes.
2. A 58-year-old man with type 2 diabetes and chronic kidney disease stage G4 (eGFR 25 mL/min/1.73m²) presents for follow-up. He complains of increasing fatigue. His medications include lisinopril, metformin, and atorvastatin. Laboratory studies show a hemoglobin of 9.8 g/dL. Iron studies show a serum ferritin of 80 ng/mL and a transferrin saturation (TSAT) of 15%.
   Answer: Initiate a trial of oral ferrous sulfate. The patient has anemia of chronic kidney disease. Before initiating an erythropoiesis-stimulating agent (ESA) like epoetin alfa, it is essential to ensure adequate iron stores. A transferrin saturation (TSAT) less than 30% and a ferritin less than 500 ng/mL indicate a need for iron supplementation. This patient has a TSAT of 15% and a ferritin of 80 ng/mL, indicating iron deficiency. Therefore, the first step is to replete iron stores with oral or intravenous iron. Oral iron is a reasonable first choice.
3. A 44-year-old man received a living-donor kidney transplant 3 years ago; he has stable function and takes tacrolimus, mycophenolate, and prednisone 5 mg daily. He also takes lisinopril for proteinuria and atorvastatin. He reports no symptoms. BP is 128/76 mm Hg. Labs: creatinine 1.6 mg/dL (baseline 1.6), eGFR 48 mL/min/1.73 m², K 5.8 mEq/L, HCO3 23 mEq/L, tacrolimus trough 7 ng/mL. Urinalysis shows trace protein. Ultrasound shows no obstruction. Which medication adjustment is most appropriate for this patient?
   Answer: Add patiromer while continuing lisinopril therapy This question tests chronic kidney disease management skills, specifically focusing on evidence-based management of hyperkalemia in post-transplant patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's hyperkalemia with RAAS inhibition indicates the need for a binder to preserve antiproteinuric therapy. The correct choice, adding patiromer while continuing lisinopril therapy, accurately reflects current guidelines for managing post-transplant CKD, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest stopping mycophenolate, which is unrelated to hyperkalemia, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for electrolyte management post-transplant, regularly review drug interactions, and practice optimizing immunosuppression with comorbidities.
4. A 65-year-old woman with chronic kidney disease stage G5 (eGFR 12 mL/min/1.73m²), not yet on dialysis, has follow-up labs. Her medications include calcium carbonate as a phosphate binder. Laboratory results are: serum calcium 8.2 mg/dL, serum phosphorus 6.5 mg/dL, and intact parathyroid hormone (PTH) 850 pg/mL. She has been adherent to a low-phosphorus diet.
   Answer: Switch calcium carbonate to sevelamer hydrochloride. This patient has severe secondary hyperparathyroidism and uncontrolled hyperphosphatemia despite being on a calcium-based phosphate binder. The primary goal is to control the hyperphosphatemia. Continuing or increasing calcium carbonate would increase the calcium load, risking vascular calcification. Switching to a non-calcium-based phosphate binder like sevelamer is the most appropriate next step to lower phosphorus levels without increasing calcium intake. Calcitriol would worsen hyperphosphatemia, and cinacalcet is typically considered after phosphorus is better controlled.
5. A 75-year-old woman on maintenance hemodialysis complains of severe, generalized itching that significantly impacts her sleep and quality of life. Her symptoms have not improved with aggressive use of emollients and over-the-counter oral antihistamines. Examination reveals dry skin with numerous excoriations but no primary rash. Her pre-dialysis labs are well-controlled, including phosphorus and PTH.
   Answer: Initiate a trial of low-dose gabapentin after dialysis. This patient has uremic pruritus refractory to initial conservative management. Gabapentinoids (gabapentin and pregabalin) are considered first-line pharmacologic therapy for moderate-to-severe uremic pruritus. A skin biopsy is not indicated without a primary rash. Topical corticosteroids are ineffective as the condition is not primarily inflammatory. Increasing dialysis frequency may help but is a significant intervention, whereas a trial of gabapentin is a standard and effective next step.
6. A 62-year-old man has CKD stage 4 for 7 years from diabetes; he follows dietary counseling and takes insulin, losartan 100 mg daily, amlodipine 10 mg daily, and furosemide 40 mg daily. He reports worsening restless legs and fatigue for 1 year. BP is 138/80 mm Hg. Exam shows pallor. Labs: creatinine 3.3 mg/dL, eGFR 19 mL/min/1.73 m², Hgb 9.6 g/dL, ferritin 380 ng/mL, transferrin saturation 14%, Ca 8.7 mg/dL, phosphate 4.8 mg/dL. Renal ultrasound shows chronic changes only. What is the next best step in managing this patient's CKD?
   Answer: Administer intravenous iron for functional iron deficiency This question tests chronic kidney disease management skills, specifically focusing on evidence-based treatment for anemia with functional iron deficiency in CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's low transferrin saturation despite high ferritin indicates functional iron deficiency, requiring IV iron. The correct choice, administering intravenous iron for functional iron deficiency, accurately reflects current guidelines for managing anemia in CKD stage 4, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest transfusing RBCs first, which is not preferred due to risks, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for CKD anemia, regularly review iron studies, and practice distinguishing absolute from functional deficiencies.
7. A 45-year-old man is newly diagnosed with CKD stage G3a (eGFR 58 mL/min/1.73m²) secondary to hypertension. His blood pressure is well-controlled with ramipril. He smokes one pack of cigarettes per day and frequently uses over-the-counter ibuprofen for chronic back pain. Which of the following interventions is most critical for slowing the progression of his kidney disease?
   Answer: Discontinuation of ibuprofen Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen are directly nephrotoxic. They inhibit prostaglandin synthesis, leading to afferent arteriolar vasoconstriction, which reduces renal blood flow and GFR. Chronic use can lead to interstitial nephritis and accelerate the progression of CKD. Stopping this direct nephrotoxin is the most important intervention. While smoking cessation and sodium restriction are important for overall cardiovascular and renal health, stopping the ongoing direct renal insult from NSAIDs is the highest priority.
8. A 55-year-old man has CKD stage 3b for 4 years due to diabetes and hypertension; he exercises and limits sodium. Medications include metformin 1,000 mg twice daily, glyburide 5 mg daily, lisinopril 20 mg daily, and atorvastatin 40 mg nightly. He has no hypoglycemia awareness issues but reports two recent episodes of lightheadedness before lunch. BP is 124/70 mm Hg. Labs: creatinine 2.0 mg/dL, eGFR 32 mL/min/1.73 m², K 4.5 mEq/L. Which medication adjustment is most appropriate for this patient?
   Answer: Discontinue glyburide and use glipizide instead This question tests chronic kidney disease management skills, specifically focusing on evidence-based adjustments for hypoglycemic agents in CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's hypoglycemia episodes and use of long-acting sulfonylurea indicate the need to switch to a shorter-acting agent. The correct choice, discontinuing glyburide and using glipizide instead, accurately reflects current guidelines for managing diabetes in CKD stage 3b, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest increasing glyburide, which worsens hypoglycemia risk, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for antidiabetic therapy in CKD, regularly review medication clearance, and practice recognizing drug-related adverse events.
9. A 59-year-old man has CKD stage 3b for 5 years from diabetes; he limits sodium and takes losartan 100 mg daily, empagliflozin 10 mg daily, metformin 500 mg twice daily, and atorvastatin 40 mg nightly. He reports no symptoms. BP is 118/66 mm Hg. Exam is normal. Labs: creatinine 2.1 mg/dL, eGFR 33 mL/min/1.73 m², K 4.8 mEq/L, HCO3 24 mEq/L. Urine albumin-to-creatinine ratio is 120 mg/g. What complication is this patient at highest risk for?
   Answer: Cardiovascular disease events related to CKD This question tests chronic kidney disease management skills, specifically focusing on identifying cardiovascular risks in diabetic CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's diabetes, CKD, and albuminuria place him at high risk for cardiovascular events. The correct choice, cardiovascular disease events related to CKD, accurately reflects current guidelines for risk assessment in CKD stage 3b, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest nephrolithiasis, which is not supported by labs, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for CVD in CKD, regularly review risk factors, and practice stratifying patients for preventive care.
10. A 56-year-old woman has CKD stage 3b for 5 years from hypertension; she limits sodium and takes lisinopril 20 mg daily and amlodipine 10 mg daily. She develops chronic knee pain from osteoarthritis and asks about analgesics. BP is 124/76 mm Hg. Exam shows knee crepitus. Labs: creatinine 1.9 mg/dL, eGFR 37 mL/min/1.73 m², K 4.6 mEq/L. What is the next best step in managing this patient's CKD?
    Answer: Recommend acetaminophen and topical NSAID as needed This question tests chronic kidney disease management skills, specifically focusing on evidence-based analgesic selection in CKD patients with osteoarthritis. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's chronic pain and CKD indicate the need for kidney-safe options like acetaminophen and limited topical NSAIDs. The correct choice, recommending acetaminophen and topical NSAID as needed, accurately reflects current guidelines for managing pain in CKD stage 3b, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest daily oral naproxen, which risks worsening renal function, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for analgesia in CKD, regularly review nephrotoxic agents, and practice balancing pain control with renal safety.
11. A 62-year-old woman with type 2 diabetes and chronic kidney disease stage G3b (eGFR 35 mL/min/1.73m²) has an HbA1c of 8.2%. Her urine albumin-to-creatinine ratio is 250 mg/g. Her current medications are metformin and glipizide. Which medication should be added to her regimen to provide the greatest benefit for slowing the progression of her diabetic kidney disease?
    Answer: Empagliflozin In patients with type 2 diabetes and albuminuric chronic kidney disease, SGLT2 inhibitors (e.g., empagliflozin, canagliflozin, dapagliflozin) have been shown to reduce the risk of CKD progression and cardiovascular events. They are recommended for patients with an eGFR ≥30 mL/min/1.73m². While other agents can lower glucose, SGLT2 inhibitors offer specific, proven renoprotective benefits in this patient population.
12. A 63-year-old man has CKD stage 4 for 6 years from diabetes; he follows low-sodium diet and takes losartan 100 mg daily, amlodipine 10 mg daily, insulin, and atorvastatin. He reports no symptoms. BP is 130/76 mm Hg. Exam shows mild pedal edema. Labs: creatinine 3.0 mg/dL, eGFR 20 mL/min/1.73 m², K 4.7 mEq/L, HCO3 22 mEq/L, Ca 8.8 mg/dL, phosphate 5.1 mg/dL, PTH 320 pg/mL. Which complication is this patient at highest risk for?
    Answer: Secondary hyperparathyroidism with renal osteodystrophy This question tests chronic kidney disease management skills, specifically focusing on identifying risks for mineral bone disorder complications in CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's elevated PTH and hyperphosphatemia indicate secondary hyperparathyroidism, increasing risk for bone disease. The correct choice, secondary hyperparathyroidism with renal osteodystrophy, accurately reflects current guidelines for recognizing CKD-MBD risks in stage 4, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest rapidly progressive GN, which is unlikely without acute changes, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for CKD complications, regularly review PTH and phosphate levels, and practice predicting long-term risks in renal patients.
13. A 52-year-old man has CKD stage 3a for 3 years from type 2 diabetes and hypertension; he has worked on weight loss and limits sodium. Medications are metformin 500 mg twice daily, empagliflozin 10 mg daily, lisinopril 10 mg daily, and rosuvastatin 20 mg nightly. He has no dyspnea, edema, or urinary symptoms. BP is 122/70 mm Hg. Exam is normal. Labs: creatinine 1.4 mg/dL, eGFR 56 mL/min/1.73 m², K 4.6 mEq/L, HCO3 24 mEq/L. Urine albumin-to-creatinine ratio is 980 mg/g on two occasions. HbA1c is 7.4%. Renal ultrasound 2 years ago is normal. What is the next best step in managing this patient's CKD?
    Answer: Add finerenone for persistent albuminuria This question tests chronic kidney disease management skills, specifically focusing on evidence-based treatment strategies for persistent albuminuria in diabetic CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's high albumin-to-creatinine ratio despite SGLT2 and ACE inhibition indicates the need for additional antiproteinuric therapy. The correct choice, adding finerenone for persistent albuminuria, accurately reflects current guidelines for managing CKD stage 3a in diabetes, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest stopping empagliflozin, which is contraindicated as it provides cardiorenal protection, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for proteinuria management in CKD, regularly review emerging therapies like mineralocorticoid antagonists, and practice interpreting urine albumin levels in diabetic patients.
14. A 49-year-old man has CKD stage 3b for 2 years from IgA nephropathy; he is managed with low-sodium diet and RAAS blockade. Medications include lisinopril 20 mg daily and atorvastatin 20 mg nightly. He asks about diet. BP is 124/72 mm Hg. Exam is normal. Labs: creatinine 1.9 mg/dL, eGFR 38 mL/min/1.73 m², K 4.7 mEq/L, HCO3 23 mEq/L. Urine protein-to-creatinine ratio is 1.2 g/g. What dietary advice should be given?
    Answer: Limit sodium intake to under 2 g daily This question tests chronic kidney disease management skills, specifically focusing on evidence-based dietary recommendations for CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's proteinuria and stable electrolytes indicate the need for sodium restriction to control blood pressure and reduce progression. The correct choice, limiting sodium intake to under 2 g daily, accurately reflects current guidelines for managing CKD stage 3b, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest increasing protein intake, which can worsen proteinuria, highlighting a frequent misconception. To improve understanding, students should focus on nutritional guidelines for CKD, regularly review dietary impacts on renal function, and practice counseling patients on lifestyle modifications.
15. A 68-year-old man with chronic kidney disease stage G4 (eGFR 28 mL/min/1.73m²) is admitted for severe cellulitis of the lower leg. He has a history of anaphylaxis to penicillin. The physician plans to start empiric antibiotic coverage for both MRSA and Pseudomonas aeruginosa. Which antibiotic regimen requires the most careful dose adjustment and therapeutic monitoring due to his renal impairment?
    Answer: Vancomycin and tobramycin Both vancomycin and aminoglycosides (like tobramycin) are primarily cleared by the kidneys and have significant nephrotoxicity and other toxicities (ototoxicity for aminoglycosides). They have narrow therapeutic windows, requiring careful initial dose adjustment based on eGFR and subsequent therapeutic drug monitoring (trough levels) to ensure efficacy and minimize toxicity. The other regimens contain agents that either do not require renal dose adjustment or require less intensive monitoring.
16. eGFR 28, elective CT with IV contrast. Best preventive measure?
    Answer: Normal saline IV 1 mL/kg/h With eGFR 28, the main risk is contrast-induced AKI, and isotonic IV saline at 1 mL/kg/h before and after contrast is the proven preventive measure. N-acetylcysteine is tempting but high-quality data show it does not reduce AKI risk, so fluid expansion with normal saline is the standard of care.
17. A 52-year-old man on maintenance hemodialysis has persistent hyperphosphatemia, with a pre-dialysis phosphorus level of 7.5 mg/dL. He has received extensive dietary counseling. He is currently taking calcium acetate 1334 mg (2 tablets) with each meal. His serum calcium is 9.2 mg/dL.
    Answer: Add a non-calcium-based phosphate binder such as sevelamer. When managing hyperphosphatemia in dialysis patients, you must balance effective phosphorus control with avoiding complications from excessive calcium intake. This patient's phosphorus remains dangerously elevated at 7.5 mg/dL (normal: 2.5-4.5 mg/dL) despite dietary counseling and calcium acetate therapy. The correct approach is D) Add a non-calcium-based phosphate binder such as sevelamer. Current guidelines recommend limiting elemental calcium intake from binders to 1.5 grams daily to prevent vascular calcification and cardiovascular complications. This patient is already receiving significant calcium from his current regimen, and his phosphorus control remains inadequate. Adding sevelamer provides additional phosphorus binding without further calcium loading. A) Increasing calcium acetate to 4 tablets would exceed safe calcium intake limits and increase cardiovascular risk without necessarily improving phosphorus control. B) Switching to calcium carbonate offers no advantage over calcium acetate for phosphorus binding and still presents the same calcium overload concerns. C) Urgent parathyroidectomy is premature—this procedure is reserved for severe, refractory hyperparathyroidism with complications, not isolated hyperphosphatemia that hasn't been optimally managed medically. Key strategy: In dialysis patients with persistent hyperphosphatemia on calcium-based binders, think "calcium limit reached" and move to non-calcium alternatives like sevelamer or lanthanum carbonate. The USMLE Step 3 often tests your knowledge of when to escalate therapy while avoiding iatrogenic complications from overtreatment with calcium-containing medications.
18. A 72-year-old woman has CKD stage 4 for 8 years from hypertension; she is managed with diet and medications. Current medications include lisinopril 10 mg daily, amlodipine 5 mg daily, furosemide 20 mg daily, and calcium carbonate as needed for reflux. She reports constipation and pruritus. BP is 142/82 mm Hg. Exam shows excoriations and mild edema. Labs: creatinine 3.2 mg/dL, eGFR 19 mL/min/1.73 m², Ca 9.7 mg/dL, phosphate 6.0 mg/dL, PTH 410 pg/mL. Which medication adjustment is most appropriate for this patient?
    Answer: Switch calcium carbonate to sevelamer with meals This question tests chronic kidney disease management skills, specifically focusing on evidence-based phosphate binder selection in CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's hypercalcemia from calcium carbonate indicates the need for a non-calcium binder to control phosphate. The correct choice, switching calcium carbonate to sevelamer with meals, accurately reflects current guidelines for managing hyperphosphatemia in CKD stage 4, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest adding calcitriol first, which can worsen hypercalcemia, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for CKD-MBD therapy, regularly review binder side effects, and practice selecting agents based on lab profiles.
19. A 67-year-old man has CKD stage 4 for 6 years from diabetes; he follows renal diet counseling and takes insulin, losartan 100 mg daily, amlodipine 10 mg daily, and furosemide 40 mg daily. He reports no symptoms. BP is 130/78 mm Hg. Labs: creatinine 3.2 mg/dL, eGFR 19 mL/min/1.73 m², HCO3 16 mEq/L, K 4.9 mEq/L. Urinalysis is bland. Renal ultrasound shows chronic changes. What is the next best step in managing this patient's CKD?
    Answer: Start oral sodium bicarbonate to correct acidosis This question tests chronic kidney disease management skills, specifically focusing on evidence-based treatment for metabolic acidosis in CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's low bicarbonate indicates acidosis, requiring alkali supplementation to prevent complications. The correct choice, starting oral sodium bicarbonate to correct acidosis, accurately reflects current guidelines for managing CKD stage 4, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest immediate dialysis, which is not indicated without other uremic signs, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for acid-base disorders in CKD, regularly review bicarbonate levels, and practice recognizing indications for therapy initiation.
20. A 66-year-old man has CKD stage 5 for 9 years from diabetes; he is stable and not on dialysis. He takes insulin, carvedilol 12.5 mg twice daily, amlodipine 10 mg daily, torsemide 40 mg daily, and sevelamer with meals. He reports decreased appetite and mild nausea but no dyspnea or confusion. BP is 148/84 mm Hg. Exam shows 1+ edema. Labs: creatinine 6.2 mg/dL, eGFR 9 mL/min/1.73 m², K 5.1 mEq/L, HCO3 18 mEq/L, Ca 8.6 mg/dL, phosphate 6.4 mg/dL, Hgb 10.1 g/dL. Renal ultrasound shows small echogenic kidneys. Which referral is most appropriate for this patient?
    Answer: Nephrology for renal replacement therapy education and planning This question tests chronic kidney disease management skills, specifically focusing on evidence-based referral timing for renal replacement therapy in advanced CKD patients. Chronic kidney disease management involves regular monitoring of renal function, adjusting medications based on kidney status, and managing complications like anemia and electrolyte imbalances. In the presented vignette, the patient's eGFR of 9 and uremic symptoms indicate the need for predialysis education and planning. The correct choice, nephrology for renal replacement therapy education and planning, accurately reflects current guidelines for managing CKD stage 5, demonstrating the student's understanding of appropriate clinical interventions. A common distractor may suggest cardiology for stress testing, which is not routinely required, highlighting a frequent misconception. To improve understanding, students should focus on guidelines for dialysis initiation, regularly review eGFR trends, and practice identifying indications for specialist referral.

Start this quiz