Free nephrology board questions: CKD Management

A 65-year-old man with CKD stage 4 is seen in the nephrology clinic for routine follow-up. His past medical history includes hypertension and coronary artery disease treated with percutaneous transluminal coronary angioplasty and stenting over 10 years ago. His medications include losartan, aspirin, metoprolol, furosemide, and simvastatin. His BP is 128/70 mm Hg, and his physical examination is unremarkable. Laboratory data: potassium 5.1 mEq/L (reference 3.5–5.0); total CO₂ 17 mEq/L (23–28); creatinine 2.7 mg/dL (baseline) (0.7–1.3); eGFR 25 mL/min/1.73 m² (≥60); calcium 9.2 mg/dL (8.6–10.2); phosphorus 4.7 mg/dL (3.0–4.5). Urine albumin-to-creatinine ratio is <30 mg/g (reference range, <30). Which ONE of the following is the BEST next step in management of this patient's electrolyte abnormalities?

A 45-year-old healthy man with serum creatinine 1.2 mg/dL (no CKD risk factors, no proteinuria) undergoes a routine health check. His eGFR calculated by the MDRD equation is 61 mL/min/1.73m² (GFR category G2), but by the 2021 CKD-EPI equation it is 74 mL/min/1.73m² (normal). Which of the following best explains this discrepancy and the preferred approach?

A 55-year-old man with CKD G4 (eGFR 22 mL/min/1.73m²) and no prior biochemical abnormalities of CKD-MBD is seen in nephrology clinic. According to KDIGO 2017 CKD-MBD guidelines, what is the recommended monitoring frequency for serum calcium and phosphate, and for PTH?

A 59-year-old man with stage 5 CKD attends clinic and denies symptoms. He is hemodynamically stable with a clear chest and mild lower-limb edema, but a pericardial friction rub is heard on auscultation. His AV fistula is still maturing. Laboratory studies show markedly elevated urea and creatinine, potassium 5.1 mmol/L, and bicarbonate 19 mmol/L. Which of the following is the most appropriate next step?

A 60-year-old man with CKD G3b/A1 attributed to ADPKD presents to the emergency department with worsening abdominal pain. Pain is localized to the left flank and has worsened over the last 3 days, accompanied by occasional fever and chills. Kidney function has been stable, and CT scan of the abdomen 2 months ago showed numerous cortical cysts in the kidneys, liver, and pancreas, stable in size over the last 2 years. Many of the cysts had measured density consistent with hemorrhage, although the patient was asymptomatic at the time of the study. Medications include lisinopril and atorvastatin. BP is 116/76 mm Hg, heart rate is 98/min, and temperature is 39°C. Physical examination reveals a protuberant abdomen with mild tenderness to deep palpation of the left upper quadrant and left flank. Laboratory data are significant for WBC count 14,000/µL (reference range, 4000‒11,000) and C-reactive protein 10.1 mg/dL (reference range, ≤0.8). Hemoglobin is 14.5 g/dL and unchanged from baseline (reference range, 14–18). A urinalysis and urine culture are sent. Which of the following is the best next step in management?

A 55-year-old man with CKD stage 4 attributed to type 2 diabetes and hypertension presents for follow-up. The patient reports feeling well. He is adherent to his medication regimen, which includes lisinopril, glipizide, and atorvastatin. At his last visit 6 months ago, the patient was reluctant to add any new medications but was agreeable to dietary changes. His BP is 125/75 mm Hg, and he has no peripheral edema. The remainder of the physical exam is normal. Laboratory data (6 months ago; current): potassium 4.2 mEq/L; 5.0 mEq/L (reference 3.5–5.0); total CO₂ 16 mEq/L; 19 mEq/L (23–28); creatinine 2.10 mg/dL; 2.0 mg/dL (0.7–1.3); BUN 14 mg/dL; 15 mg/dL (8–20); phosphorus 3.5 mg/dL; 3.3 mg/dL (3.0–4.5); hemoglobin A1c 7.5%; 7.2% (4.0–5.6). Increased dietary intake of which of the following MOST LIKELY accounts for the observed changes?

A clinician is choosing between the CKD-EPI and MDRD creatinine-based equations to estimate GFR. Which of the following statements comparing these equations is correct?

A 50-year-old female with chronic hepatitis C presents with nephrotic range proteinuria and a recent kidney biopsy shows membranoproliferative glomerulonephritis (MPGN). What is the recommended treatment approach for her kidney disease?

A 68-year-old man with G3b/A3 CKD (biopsy showing arterionephrosclerosis) returns for hypertension management. His blood pressure remains above goal on chlorthalidone. Lisinopril was discontinued because of significant hyperkalemia (potassium 5.9 mEq/L) despite a potassium-restricted diet, and an ARB is expected to pose the same risk. His resting heart rate is 52 beats/min and ECG shows first-degree AV block. Which of the following is the most appropriate agent to add for blood-pressure control?

A pregnant woman with CKD is seen for a routine first-trimester visit. She is asymptomatic, but a screening urine culture grows Escherichia coli at greater than 100,000 CFU/mL. Which of the following is the most appropriate antibiotic to treat her asymptomatic bacteriuria?

A 68-year-old man with CKD stage 3b, hypertension, and type 2 diabetes is seen 3 months after his third episode within a year of acute pain and swelling of the right first metatarsophalangeal joint. He was treated with colchicine and then maintenance allopurinol, and symptoms resolved. Medications are allopurinol 50 mg, lisinopril 10 mg, amlodipine 5 mg, and furosemide 40 mg. Examination is unremarkable. K 4.9 mEq/L; creatinine 1.9 mg/dL; uric acid 6.9 mg/dL (reference 3–7); AST 32 and ALT 25 U/L. What is the most appropriate next step?

A 45-year-old man with CKD G5 (eGFR 6 mL/min, BUN 140 mg/dL) not yet on dialysis presents with pleuritic chest pain, positional (worse supine, better leaning forward), and a friction rub on auscultation. ECG shows diffuse saddle-shaped ST elevation and PR depression. Echo: moderate pericardial effusion without tamponade. Which is the most appropriate immediate management?