Fatal hyperammonemia caused by Mycoplasma hominis infection: A rare case report

Hyperammonemia, a clinical condition characterized by elevated serum ammonia levels, often leads to altered consciousness and can have severe neurological consequences. It predominantly affects patients with hyperammonemic encephalopathy (HE), urea cycle defects, medication-induced causes, or renal dysfunction. Herein, we report a rare fatal case of hyperammonemia triggered by Mycoplasma hominis infection, which presented with empyema and impaired consciousness. This case underscores the importance of recognizing non-hepatic etiologies of hyperammonemia, particularly infections caused by urease-producing pathogens like M. hominis, which can hydrolyze urea to ammonia, thereby driving up serum ammonia levels. We further review the diverse etiologies of hyperammonemia, emphasize the diagnostic challenges posed by non-hepatic causes-often overlooked in routine clinical evaluations-and discuss key therapeutic considerations, including prompt antimicrobial therapy, ammonia-lowering interventions, and management of underlying infection to improve patient outcomes.