A 72-year-old man comes to the emergency department due to 2 days of increasing shortness of breath. He has been recovering from an upper respiratory infection that started 4 days ago. The patient has been drinking plenty of water and taking ibuprofen for headache and muscle aches. Medical history is significant for congestive heart failure, coronary artery disease, and type 2 diabetes mellitus. On examination, temperature is 38 C (100.4 F), blood pressure is 130/84 mm Hg, pulse is 104/min, and respirations are 22/min. Oxygen saturation is 94% on room air. Bilateral crackles are present in both lower lobes. No extremity edema is present. Chest x-ray reveals bilateral infiltrates. The patient is given ceftriaxone and azithromycin and one dose of intravenous furosemide. The next day, his dyspnea improved markedly. Repeat chest x-ray reveals marked decrease in bilateral infiltrates. What is the most likely cause of this patient's acute presentation?

Question

A 72-year-old man comes to the emergency department due to 2 days of increasing shortness of breath.  He has been recovering from an upper respiratory infection that started 4 days ago.  The patient has been drinking plenty of water and taking ibuprofen for headache and muscle aches.  Medical history is significant for congestive heart failure, coronary artery disease, and type 2 diabetes mellitus.  On examination, temperature is 38 C (100.4 F), blood pressure is 130/84 mm Hg, pulse is 104/min, and respirations are 22/min.  Oxygen saturation is 94% on room air.  Bilateral crackles are present in both lower lobes.  No extremity edema is present.  Chest x-ray reveals bilateral infiltrates.  The patient is given ceftriaxone and azithromycin and one dose of intravenous furosemide.  The next day, his dyspnea improved markedly.  Repeat chest x-ray reveals marked decrease in bilateral infiltrates.  What is the most likely cause of this patient's acute presentation?

Quizplus · Accepted Answer

This patient with a history of congestive heart failure (CHF) and recent upper respiratory infection (URI) has dyspnea, low-grade fever, bilateral pulmonary infiltrates, and hypoxia, raising concern for both pneumonia (treated with antibiotics) and CHF exacerbation (treated with diuretic therapy). However, although symptoms (eg, dyspnea) of bacterial pneumonia can improve rapidly following the administration of antibiotics, the corresponding pulmonary infiltrate takes weeks or months to resolve due to the presence of leukocytes and inflammatory byproducts in the alveolar space. Therefore, the rapid resolution of a pulmonary infiltrate on chest x-ray makes pneumonia unlikely (Choices D, E, and F). Given this patient's history of CHF and the rapid improvement in his symptoms and pulmonary infiltrate with the administration of furosemide, he most likely had a CHF exacerbation with pulmonary edema. Left-sided heart failure often causes bilateral pulmonary infiltrates due to fluid extravasation into alveolar space from elevated pulmonary vascular pressures; administering diuretics reduces intravascular volume, which can rapidly improve pulmonary edema (eg, pulmonary infiltrates, dyspnea, hypoxia). Lower extremity edema is not always present. Heart failure can be precipitated by infection (eg, URI, the likely cause of this patient's fever) and is often exacerbated by nonsteroidal anti-inflammatory drugs (eg, ibuprofen), which increase sodium retention in the kidneys. (Choice A) Atelectasis often causes bilateral pulmonary opacities in the lower portions of the lungs and can resolve quickly with improved aeration. However, in an ambulatory patient, fever, hypoxia, and 2 days of dyspnea are unlikely due to atelectasis, and rapid symptom and infiltrate resolution with diuretic therapy is consistent with CHF exacerbation. (Choice C) Subacute hypersensitivity pneumonitis can present with symptoms similar to a viral infection (eg, fever, malaise, nausea). However, patients usually have a history of exposure to aerosolized irritants, ground glass opacities are typically seen in the mid-upper portions of the lung, and chest x-ray findings would take weeks or months to resolve (because it is inflammatory). Educational objective: Congestive heart failure (CHF) frequently causes bilateral pulmonary infiltrates on chest x-ray. In contrast to bacterial or viral pneumonia, which cause prolonged chest x-ray findings, patients with CHF can have rapid resolution of chest x-ray findings following diuretic administration.

A 72-Year-Old Man Comes to the Emergency Department Due to 2