Severe Aortic and Mitral Regurgitation Secondary to Infective Endocarditis Presenting as Acute Respiratory Failure

Infective endocarditis (IE) typically presents with fever, a new or changing cardiac murmur, and embolic phenomena. Acute respiratory failure (ARF) as the dominant presenting feature, without overt cardiac signs, is uncommon and creates significant diagnostic challenges. We present a previously healthy 24-year-old man who attended the Emergency Department with fever, productive cough, and ARF requiring mechanical ventilation for bilateral pulmonary infiltrates. Cardiovascular examination on admission was unremarkable: there was no audible cardiac murmur and no peripheral stigmata of IE. Blood cultures subsequently yielded Staphylococcus aureus. Following initial extubation on day 4, the patient deteriorated rapidly within 12 hours, necessitating reintubation. The emergence of a new diastolic murmur prompted urgent echocardiography, revealing large mobile vegetations on both the aortic and mitral valves with severe regurgitation of each, consistent with left-sided IE. Definite IE was confirmed by two major modified Duke criteria. Emergency double mechanical valve replacement was performed on day 6, with the patient discharged on day 14 on lifelong anticoagulation. This case illustrates that acute severe valvular regurgitation in IE can precipitate cardiogenic pulmonary edema closely mimicking acute respiratory distress syndrome (ARDS). Concomitant aortic and mitral valve involvement likely resulted from contiguous spread via the aorto-mitral curtain. Crucially, the absence of a murmur or peripheral stigmata of IE on initial examination did not exclude the diagnosis. Early echocardiographic evaluation in unexplained ARF is paramount, particularly in the context of staphylococcal bacteremia.