Hyperammonemia Presenting as Refractory Status Epilepticus after Lung Transplant in a Patient Positive for Ureaplasma parvum

Abstract

Hyperammonemia is a rare complication of lung transplant with a high mortality rate. It presents as encephalopathy and progresses to seizures, status epilepticus, coma, cerebral edema, and brain death. Multiple treatments have been documented including administration of medications, gut decontamination, and dialysis. However, no definitive treatments exist and mortality remains between 67% and 75%. We present the case of a 65-year-old male with idiopathic pulmonary fibrosis who developed refractory status epilepticus secondary to hyperammonemia following lung transplant. The patient presented on postoperative day 7 with super-refractory status epilepticus and normal computed tomography scan of the head. Hyperammonemia was suspected due to refractory seizures and confirmed with peak ammonia level >1000 μmol/L. Despite aggressive treatment, the patient developed global cerebral edema and died. Postmortem investigations revealed that the patient was positive for Ureaplasma parvum. Additional studies are needed to elucidate the exact mechanism of disease and investigate successful treatment options.

Keywords: Cerebral edema; hyperammonemia; lung transplantation; seizures; status epilepticus.

Figure 1

The figure demonstrates focal seizures in the left frontal, temporal, and parietal lobes

Figure 2

The image on the right is the computed tomography scan of the head that was done at the time of the patient's first seizure. The image on the left was captured 2 days later when the patient experienced neurologic deterioration, and it shows diffuse cerebral edema. An external ventricular device had already been placed in this image