The One-Sided Flood: A Case of Unilateral Pulmonary Edema.

Unilateral pulmonary edema (UPE) is an uncommon clinical presentation, accounting for approximately 2% of cardiogenic pulmonary edema cases, and often mimics pulmonary infections, leading to diagnostic delays. We report the case of a 51-year-old woman with rheumatic heart disease who presented with progressive dyspnea and pedal edema. Clinical findings suggested pulmonary edema, but chest radiography revealed predominantly left-sided congestion. Point-of-care ultrasound demonstrated a unilateral B-profile, and bedside transthoracic echocardiography identified severe mitral regurgitation with an eccentric jet directed toward the left pulmonary veins, led to elevated pulmonary venous pressure on left side, resulting in predominantly left sided pulmonary edema. The patient responded well to intravenous diuretics and non-invasive ventilatory support, with antibiotics discontinued after exclusion of infection. She was discharged in stable condition and scheduled for elective mitral valve replacement. This case highlights the diagnostic challenges of UPE, the pivotal role of point-of-care ultrasound in differentiating it from pneumonia, and the importance of considering both cardiac and infectious etiologies to optimize patient outcomes.