A 64-year-old woman is brought to the triage desk by her family due to extreme lightheaded… — USMLE Step 2 CK

A $64$ -year-old woman is brought to the triage desk by her family due to extreme lightheadedness and a progressive inability to catch her breath over the past three days. She has a medical history significant for severe rheumatoid arthritis and chronic obstructive pulmonary disease. Two weeks ago, she experienced a self-limiting febrile viral illness. On examination, the patient appears visibly distressed and diaphoretic. Vital signs show a temperature of $37.1^\circ\text{C}$ ( $98.8^\circ\text{F}$ ), heart rate of $118\text{/min}$ , respiratory rate of $24\text{/min}$ , and blood pressure of $86/60\text{ mmHg}$ . During normal inspiration, her systolic blood pressure decreases by $18\text{ mmHg}$ . Jugular venous distention is prominent up to the angle of the mandible while she sits upright. Pulmonary auscultation reveals globally distant breath sounds but no crackles or active wheezing. Cardiac auscultation is limited by an increased anterior-posterior chest diameter, and no murmurs are appreciated. An electrocardiogram demonstrates a regular tachycardia with low-voltage QRS complexes in the limb leads and shifting electrical axes. Which of the following is the most appropriate next step in management?

Performance of urgent bedside echocardiographyAnswer
B
Administration of systemic glucocorticoids and inhaled bronchodilators
C
Intravenous administration of furosemide
D
Transport for computed tomography angiography of the chest
E
Initiation of intravenous vancomycin and piperacillin-tazobactam

Answer

Performance of urgent bedside echocardiography

The correct answer is performance of urgent bedside echocardiography. This patient is presenting with classic signs of cardiac tamponade: hypotension, elevated jugular venous pressure, and distant heart sounds (Beck's triad). Her recent viral illness likely triggered acute pericarditis, culminating in a malignant pericardial effusion. The diagnosis is further supported by the presence of pulsus paradoxus (an exaggerated

>10\text{ mmHg}

drop in systolic pressure during inspiration due to the bowing of the interventricular septum into the left ventricle) and electrical alternans on the electrocardiogram (caused by the heart swinging back and forth within the fluid-filled pericardial sac). In a hemodynamically unstable patient, the immediate next step is point-of-care bedside echocardiography to confirm the effusion and visualize right heart collapse before proceeding to life-saving pericardiocentesis.

Step-by-Step Solution

Analyze the patient's hemodynamic profile and vital signs.

The patient is hypotensive (

86/60\text{ mmHg}

) and tachycardic, with a significant pulsus paradoxus (

18\text{ mmHg}

drop in systolic blood pressure during inspiration).

Identifying the pattern of shock is critical for triaging interventions.

Interpret the physical examination and diagnostic findings in the context of her history.

The combination of jugular venous distention, clear lungs, and low-voltage electrocardiogram with electrical alternans (shifting axes) strongly points away from her underlying chronic obstructive pulmonary disease and toward a pericardial process.

The recent viral illness likely caused acute viral pericarditis, which has now evolved into a large pericardial effusion.

Determine the optimal diagnostic or therapeutic intervention for suspected cardiac tamponade.

Urgent bedside echocardiography must be performed.

Echocardiography rapidly and noninvasively confirms the diagnosis of cardiac tamponade (showing right atrial and ventricular diastolic collapse) and helps guide immediate pericardiocentesis.

Key Concept

Diagnosis and initial management of cardiac tamponade

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