An 82-year-old nursing home patient with fever and gram-negative rods on culture develops rapid onset dyspnea with interstitial retractions and bilateral crackles. The most likely diagnosis is

• A. Influenza
• B. Acute respiratory distress syndrome
• C. Spontaneous pneumothorax
• D. Upper airway obstruction

Answer: (B)

Rapid onset difficulty breathing with diffuse intercostal retractions and bilateral crackles in the setting of fever and gram-negative sepsis points to acute respiratory distress syndrome. ARDS is a noncardiogenic pulmonary edema caused by inflammatory injury to the alveolar-capillary barrier, often triggered by sepsis from pneumonia. The resulting increased capillary permeability lets fluid flood the alveoli, causing diffuse crackles, hypoxemia, and severe respiratory distress that can progress over hours to days. This fits best with the sepsis-related lung injury described. Spontaneous pneumothorax would typically cause sudden unilateral chest symptoms with decreased breath sounds on one side; upper airway obstruction presents with stridor and prominent use of accessory muscles but not diffuse bilateral crackles; influenza can cause respiratory symptoms but ARDS describes the diffuse lung involvement and rapid respiratory decline seen here.