The Cast That Choked: Plastic Bronchitis Unmasking Corynebacterium diphtheria

Plastic bronchitis (PB) is a rare and potentially life-threatening condition characterized by formation of casts within the airways. Respiratory diphtheria caused by Corynebacterium diphtheriae can involve pseudo membrane formation extending into the lower respiratory tract; however, its association with PB remains extremely rare, with no previously reported cases in the literature. We report a 6-year-old partially immunized girl who presented with acute respiratory failure due to diphtheria-associated PB complicated by Klebsiella pneumoniae co-infection. Prompt intubation, flexible bronchoscopy, anti-diphtheria serum, and targeted antibiotic therapy led to complete recovery by day 10. This case highlights the importance of considering PB in children with unexplained respiratory failure unresponsive to standard bronchodilator therapy, particularly in settings with incomplete immunization coverage.