FATAL HYPERAMMONEMIA FOLLOWING ORTHOTOPIC LUNG TRANSPLANTATION

There have been anecdotes of unexplained coma and death in patients af ter otherwise successful orthotopic lung transplantation. A patient wi th primary pulmonary hypertension who underwent a technically uncompli cated single orthotopic lung transplantation is described, The patient developed intractable status epilepticus 4 days after surgery in asso ciation with the presence of a markedly elevated plasma ammonium level . Despite multiple therapeutic interventions, the hyperammonemia ultim ately resulted in the patient's death. Both metabolic and enzymatic st udies showed that the unique physiological disturbance in this disorde r results at least in part from defective in vivo conversion of waste nitrogen to urea and increased production of waste nitrogen, Although the rate of hepatic ureagenesis was therefore insufficient to prevent accumulation of ammonium, the cause was not severe liver disease, Live r histology showed widespread, microvesicular steatosis on light-micro scopic examination, but only electron-microscopic examination showed s evere microvesicular steatosis with severe mitochondrial injury. As in Reye's syndrome, it was unclear whether the hepatic mitochondrial inj ury played a role in development or if it was the result of hyperammon emia. We recommend that any patient with an unexplained alteration ol: mental status after solid organ transplantation be evaluated for hyper ammonemia.