A 65-year-old man is brought to the emergency department at 3:00 AM due to sudden, severe … — USMLE Step 2 CK

A 65-year-old man is brought to the emergency department at 3:00 AM due to sudden, severe difficulty breathing. He states he woke up gasping for air and had to sit upright on the edge of his bed. His medical history includes hypertension, type 2 diabetes mellitus, and a 40-pack-year smoking history. Current medications include amlodipine and metformin. His temperature is $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ), blood pressure is $185/105\text{ mmHg}$ , pulse is $112/\text{min}$ , and respirations are $28/\text{min}$ . Pulse oximetry shows an oxygen saturation of $86\%$ on room air. Physical examination reveals distended neck veins when sitting at a 45-degree angle. Cardiac auscultation reveals a regular tachycardia with a prominent third heart sound (S3). Lung auscultation reveals bilateral basilar crackles extending halfway up the posterior lung fields, without wheezing. Bilateral 1+ pitting edema is present in the lower extremities. Arterial blood gas on room air shows a pH of $7.31$ , $\text{pCO}_2$ of $52\text{ mmHg}$ , and $\text{pO}_2$ of $58\text{ mmHg}$ . Laboratory studies show a normal leukocyte count. Thyroid function tests reveal a TSH of $1.5\text{ \mu U/mL}$ (normal: $0.5-5.0$ ) and a free T4 of $0.6\text{ ng/dL}$ (normal: $0.9-2.4$ ). A Gram stain of a sputum sample reveals normal respiratory flora with no predominant organisms. Chest radiography shows bilateral fluffy alveolar opacities, prominent hila, and cephalization of the pulmonary vessels. Which of the following is the most appropriate initial step in the management of this patient?

A
Albuterol and ipratropium nebulization
B
Intravenous ceftriaxone and azithromycin
C
Intravenous sodium bicarbonate
Intravenous furosemideAnswer
E
Intravenous levothyroxine

Answer

Intravenous furosemide

The correct answer provides the mainstay treatment for acute decompensated heart failure (ADHF). The patient's presentation of paroxysmal nocturnal dyspnea, an S3 gallop, jugular venous distention, basilar crackles, and radiographic findings of alveolar opacities with cephalization are classic for ADHF. Intravenous loop diuretics, such as furosemide, are the initial pharmacotherapy of choice because they rapidly decrease circulating volume and promote venodilation, thereby reducing cardiac preload and improving pulmonary congestion.

Step-by-Step Solution

Analyze the patient's vital signs and physical examination findings.

The patient exhibits severe hypertension, hypoxia, an S3 gallop, jugular venous distention, and bilateral basilar crackles without wheezing.

To identify the primary pathophysiologic process driving the acute dyspnea.

Evaluate the laboratory and imaging results.

Chest radiography confirms cardiogenic pulmonary edema. The arterial blood gas demonstrates acute respiratory acidosis secondary to fluid accumulation in the alveoli. Infectious and primary endocrine etiologies are not supported by the normal leukocyte count, normal sputum flora, and normal TSH.

To rule out alternative diagnoses such as a COPD exacerbation, bacterial pneumonia, or a thyroid-related crisis.

Determine the most appropriate initial pharmacological management.

The standard of care for acute decompensated heart failure (ADHF) with volume overload is prompt preload reduction and diuresis with intravenous loop diuretics (e.g., furosemide), often combined with noninvasive positive pressure ventilation and vasodilators given his severe hypertension.

Intravenous furosemide provides rapid symptomatic relief by actively removing excess intravascular volume and promoting immediate venodilation.

Key Concept

Diagnosis and acute pharmacological management of acute decompensated heart failure (ADHF)

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