A 68-year-old man comes to the clinic for a follow-up visit. Two weeks ago, he was hospita… — USMLE Step 3

A 68-year-old man comes to the clinic for a follow-up visit. Two weeks ago, he was hospitalized for a mild heart failure exacerbation and was discharged in stable condition. His medical history includes ischemic cardiomyopathy with a left ventricular ejection fraction of 35%, type 2 diabetes mellitus, and hypertension. His home medications include lisinopril, carvedilol, and furosemide $40$ mg twice daily. At the time of discharge, empagliflozin was added to his regimen. Today, the patient reports feeling lightheaded when standing up from a seated position and complains of increased thirst.

Blood pressure is $110/70$ mm Hg while supine and $92/58$ mm Hg while standing. Heart rate is $72$ /min while supine and $90$ /min while standing. Physical examination reveals flat jugular veins while sitting and dry oral mucosa. Lungs are clear to auscultation.

Current laboratory results are as follows:

Laboratory Test	Result	Reference Range
Blood urea nitrogen	$36$ mg/dL	$8-20$ mg/dL
Serum creatinine	$1.6$ mg/dL	$0.7-1.3$ mg/dL
Serum sodium	$138$ mEq/L	$136-145$ mEq/L
Serum potassium	$4.1$ mEq/L	$3.5-5.0$ mEq/L

(Note: Discharge serum creatinine was $1.1$ mg/dL and BUN was $16$ mg/dL.)

Which of the following is the most appropriate next step in the management of this patient?

Decrease the furosemide doseCevap
B
Discontinue empagliflozin
C
Discontinue lisinopril
D
Administer intravenous normal saline
E
Order a renal Doppler ultrasound

Cevap

Decrease the furosemide dose

The correct action is to decrease the furosemide dose. This patient has developed symptomatic orthostatic hypotension and pre-renal acute kidney injury (BUN:Cr ratio > 20) due to intravascular volume depletion. This is a common and expected complication when an SGLT2 inhibitor (empagliflozin), which induces osmotic diuresis, is added to a regimen already containing a loop diuretic (furosemide). According to current heart failure guidelines (GDMT), medications that reduce mortality (ACE inhibitors, beta-blockers, SGLT2 inhibitors, and mineralocorticoid receptor antagonists) should be maintained if at all possible. Loop diuretics are used strictly for volume control and symptom relief; they do not improve survival. Therefore, the safest and most appropriate intervention is to reduce the dose of the loop diuretic to resolve the hypovolemia, allowing the patient to continue receiving the long-term cardioprotective and renoprotective benefits of empagliflozin and lisinopril.

Adım Adım Çözüm

Analyze the patient's vital signs and physical examination.

The patient has orthostatic hypotension (blood pressure drop of >20 mm Hg systolic upon standing), compensatory tachycardia, flat jugular veins, and dry mucous membranes, all indicating severe intravascular volume depletion.

Establishing the patient's current hemodynamic status is required to interpret the laboratory abnormalities.

Interpret the laboratory findings in the context of the physical exam.

The BUN and creatinine have risen acutely. The BUN-to-creatinine ratio is >20 (36/1.6 = 22.5), which strongly supports a pre-renal etiology (hypovolemia) rather than intrinsic renal pathology.

Helps confirm that the acute kidney injury is secondary to poor renal perfusion from volume loss.

Identify the iatrogenic cause of the hypovolemia.

The patient was recently started on empagliflozin (an SGLT2 inhibitor) which causes osmotic diuresis. Combined with his baseline furosemide, this resulted in synergistic, excessive fluid loss.

Allows targeted adjustment of the patient's pharmacotherapy.

Select the appropriate medication to adjust based on Guideline-Directed Medical Therapy (GDMT) principles.

Furosemide is reduced. Empagliflozin, lisinopril, and carvedilol all provide proven mortality benefits in HFrEF. Furosemide provides only symptomatic relief of congestion.

When facing medication-induced adverse effects, symptomatic therapies should be down-titrated first to preserve drugs that improve overall survival.

Anahtar Kavram

In patients with HFrEF who develop volume depletion after the initiation of an SGLT2 inhibitor, the dose of the concurrent loop diuretic should be reduced to correct the hypovolemia, as loop diuretics provide only symptomatic relief while SGLT2 inhibitors offer long-term mortality and renoprotective benefits.

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