Lady Windermere Syndrome Presenting As Prolonged Febrile Illness in an Immunocompetent Woman.

Lady Windermere syndrome is a distinct clinical entity associated with Mycobacterium avium complex infection that classically affects immunocompetent elderly women, particularly those with voluntary cough suppression, resulting in impaired airway clearance and mucus stasis within dependent bronchi. The condition has also been associated with a characteristic lean body habitus and thoracic skeletal abnormalities that may further compromise mucociliary clearance. We report the case of a 60-year-old woman with a history of pulmonary embolism and hypothyroidism who presented with a 45-day history of persistent nonproductive cough, intermittent fever, and right-sided chest discomfort. Physical examination revealed a lean body habitus and visible pectus excavatum. Laboratory studies demonstrated elevated inflammatory markers, and chest computed tomography showed bronchiectasis predominantly involving the middle lobe and lingula. Microbiological cultures confirmed Mycobacterium avium infection. The patient received a targeted 12-month multidrug regimen consisting of rifampicin, ethambutol, and azithromycin, achieving microbiological clearance and marked clinical improvement, with follow-up imaging demonstrating stable radiologic findings and sustained remission.