A Diagnostic Dilemma: A Case of Complicated Pneumonia With Pyelonephritis and Subclinical Myocarditis.

A 41-year-old woman presented with a 3.5-month history of fever, weakness, productive cough, and burning micturition along with generalized weakness and significant weight loss. Chest X-ray revealed bilateral infiltrates and bilateral pleural effusion, and the workup suggested community-acquired pneumonia (CAP). However, the course was complicated by persistent fevers, elevated inflammatory markers, elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP), and pelvic fluid collection. Extensive investigations, including bronchoscopy and lung biopsy, failed to identify a specific pathogen. Pulmonary vasculitis and lymphoma were ruled out. Antibiotic and corticosteroid therapy resulted in clinical improvement. While the cause remains unknown, brucellosis and aspergillosis were considered but ruled out with advanced testing. The underlying etiology remains elusive, highlighting the diagnostic challenges in CAP with atypical presentations.