Idiopathic Hyperammonemia after Orthotopic Lung Transplantation

Idiopathic hyperammonemia is characterized by increased serum ammonia levels (>200umol/L) and is sometimes associated with normal to slightly elevated liver function tests [1]. These patients often present with encephalopathy, cerebral edema, seizures, and coma. Idiopathic hyperammonemia has been reported after high dose chemotherapy, and organ transplants including Orthotopic lung transplant [2]. Hyperammonemia is a rare, severe, and often fatal complication. There are few cases reported in the literature since 1997, including one retrospective analysis of 807 lung transplants; only 8 patients were diagnosed with hyperammonemia [3]. The exact mechanism of idiopathic hyperammonemiais not fully understood with congenital or acquired defects in ammonia metabolism, as well as bacterial infection having been described [3].