USMLE PRACTICE QUESTION #47
TOPIC: Managing chronic kidney disease.
Today’s question will test your understanding of renal pathology (chronic kidney disease).
A 68-year-old male with a history of hypertension and type 2 diabetes presents to the clinic with generalized fatigue and decreased appetite over the past few weeks. His vital signs include a temperature of 98.2°F (36.8°C), blood pressure of 155/95 mmHg, heart rate of 82/minute, and respiratory rate of 16/minute. Physical examination reveals pale conjunctivae and mild bilateral lower extremity pitting edema. Labs show a serum creatinine of 4.5 mg/dL (N: 0.7-1.3 mg/dL), estimated glomerular filtration rate (eGFR) of 18 mL/min/1.73 m², hemoglobin of 9.2 g/dL, and blood urea nitrogen of 65 mg/dL. The patient is diagnosed with chronic kidney disease stage 4. Which of the following is most appropriate to delay disease progression?
A) Start angiotensin-converting enzyme inhibitor therapy
B) Initiate erythropoietin-stimulating agent therapy
C) Perform a kidney biopsy
D) Restrict dietary protein intake
E) Schedule hemodialysis
Detailed Breakdown of Answers + Correct Answer Below ⏬
ANSWER + QUESTION BREAKDOWN
The mental model for this question comes from our detailed test-taking skills masterclass (It was made for students who want to elevate their USMLE test-taking skills; if that’s you, check it out). Here’s how to think through this question:
Step 1. Determine what the question is asking: Which intervention is most appropriate to delay disease progression?
Step 2: Is this a first-, second-, or third-order question?
Answer: 1st order (The diagnosis is given; therefore, your sole job is recognizing which treatment option is most appropriate for slowing disease progression).
Step 3. Read the vignette to determine a diagnosis (it’s provided near the end of the vignette).
Step 4. Ask yourself what should be done to slow the disease progression (based on the given diagnosis).
Step 5. Look at the answer choices and select the option most closely resembling your thoughts from “Step 4” above.
GENERAL ANALYSIS
The question involves a 68-year-old male with chronic kidney disease, characterized by a severely reduced estimated glomerular filtration rate and elevated serum creatinine. The patient also presents with anemia and hypertension. The task is to determine the most appropriate intervention to delay the progression of CKD.
ANSWER CHOICES:
ANSWER CHOICE A: Start angiotensin-converting enzyme inhibitor therapy
ACE inhibitors are commonly used to manage hypertension and have a renoprotective effect by reducing glomerular pressure and slowing the progression of kidney disease.
ANSWER CHOICE B: Initiate erythropoietin-stimulating agent therapy
Erythropoietin-stimulating agents are used to treat anemia associated with CKD.
ANSWER CHOICE C: Perform a kidney biopsy
A kidney biopsy is used to diagnose specific kidney diseases. Since the diagnosis is provided in the vignette, this step is unnecessary.
ANSWER CHOICE D: Restrict dietary protein intake
Protein restriction can reduce the workload on the kidneys and decrease the production of nitrogenous waste. While beneficial, dietary protein restriction is an adjunctive measure, not the primary intervention to delay CKD progression.
ANSWER CHOICE E: Schedule hemodialysis
Hemodialysis manages end-stage renal disease by removing waste products from the blood. It is not indicated until CKD progresses to stage 5 or if severe symptoms cannot be managed otherwise.
FINAL VERDICT…
ACE inhibitors are a cornerstone in the management of chronic kidney disease, particularly in patients with hypertension and proteinuria. They work by inhibiting the conversion of angiotensin I to angiotensin II, leading to vasodilation and reduced blood pressure. This decreases intraglomerular pressure and slows the progression of kidney damage. In patients with CKD, maintaining optimal blood pressure control is crucial, and ACE inhibitors have been shown to provide renal protection beyond their blood pressure-lowering effects. Therefore, initiating ACE inhibitor therapy is the most appropriate intervention to delay the progression of CKD in this patient.
CORRECT ANSWER: A) Start angiotensin-converting enzyme inhibitor therapy
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