A 56-year-old woman presents to the clinic with a 7-month history of progressive fatigue, … — USMLE Step 3

A $56$ -year-old woman presents to the clinic with a $7$ -month history of progressive fatigue, episodic facial flushing, and chronic watery diarrhea. She also reports bilateral leg swelling that has worsened over the past few weeks. Her medical history is unremarkable, and she takes no medications. Vital signs show a temperature of $37.1^{\circ}\text{C}$ ( $98.8^{\circ}\text{F}$ ), pulse of $92\text{/min}$ , blood pressure of $115/70\text{ mmHg}$ , and respirations of $16\text{/min}$ . On physical examination, blanching telangiectasias are noted on her face and neck. Jugular venous distention is present. The abdomen is soft, but a firm, irregular liver edge is palpated $5\text{ cm}$ below the right costal margin. Cardiac auscultation reveals a prominent right ventricular heave and a grade $3/6$ holosystolic murmur best heard at the left lower sternal border. Which of the following dynamic physical examination findings is most likely to be present in this patient?

A
The holosystolic murmur becomes louder during sustained isometric handgrip.
B
Intermittent giant "a" waves are visualized in the jugular venous pulsation.
The intensity of the holosystolic murmur increases during deep inspiration.Answer
D
Systolic blood pressure decreases by $> 10\text{ mmHg}$ during normal inspiration.
E
A high-pitched, blowing, early diastolic murmur is appreciated at the right upper sternal border.

Answer

The intensity of the holosystolic murmur increases during deep inspiration.

The patient's clinical presentation of episodic facial flushing, chronic watery diarrhea, and hepatomegaly (metastatic liver disease) is highly characteristic of carcinoid syndrome. Carcinoid tumors secrete vasoactive substances, primarily serotonin. When these tumors metastasize to the liver, the hormones bypass hepatic metabolism and enter the systemic venous circulation, reaching the right side of the heart. This leads to endocardial fibrosis, characteristically causing tricuspid regurgitation and pulmonic stenosis. The left side of the heart is typically spared because serotonin is inactivated by monoamine oxidase in the pulmonary vascular bed. The patient's holosystolic murmur at the left lower sternal border is classic for tricuspid regurgitation. Dynamic auscultation of right-sided murmurs reveals an increase in intensity with deep inspiration (Carvallo's sign). Inspiration creates negative intrathoracic pressure, which increases venous return to the right heart, thereby increasing the right ventricular stroke volume and the regurgitant flow across the incompetent tricuspid valve.

Step-by-Step Solution

Synthesize the clinical presentation.

The combination of episodic facial flushing, chronic watery diarrhea, telangiectasias, and hepatomegaly strongly suggests carcinoid syndrome with liver metastases.

Identifying the underlying systemic neuroendocrine disease is required to understand the etiology of the cardiac findings.

Identify the cardiac pathology.

Metastatic carcinoid tumors release serotonin into the systemic venous circulation, causing endocardial fibrosis of the right heart and leading to tricuspid regurgitation.

Right-sided heart valves are selectively affected because vasoactive amines like serotonin are inactivated by monoamine oxidase in the lungs, sparing the left heart.

Determine the dynamic physical exam finding for tricuspid regurgitation.

Tricuspid regurgitation presents as a holosystolic murmur at the left lower sternal border that increases in intensity with deep inspiration.

Inspiration decreases intrathoracic pressure, increasing venous return to the right heart and thus increasing the right-sided regurgitant volume (Carvallo's sign).

Key Concept

Carcinoid heart disease typically causes right-sided valvular lesions, most commonly tricuspid regurgitation, the murmur of which characteristically increases in intensity with deep inspiration (Carvallo's sign).

Estimated Time:1m 30s

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