Acute hyperammonemic encephalopathy in adult onset ornithine transcarbamylase deficiency.

OBJECTIVES

To report the clinical manifestations of acute hyperammonemic encephalopathy in adult onset ornithine transcarbamylase deficiency (OTCD).

DESIGN

Case report.

SETTING

Intensive care unit of a tertiary medical centre.

PATIENT: A 48-year-old Caucasian male body builder who developed acute loss of consciousness after a febrile illness.

INTERVENTIONS: The patient was immediately started on hemodia-filtration, protein elimination and ammonia scavenging medications.

MEASUREMENTS AND

RESULTS

Serum ammonium was elevated and plasma and urine amino acids had a pattern indicative of a urea cycle defect. DNA studies revealed a mutation of the urea cycle enzyme, ornithine transcarbamylase. The encephalopathy resolved and the patient slowly recovered though with some cognitive impairment.

CONCLUSIONS

Adult presentation of OTCD is rare and the mortality and morbidity rates are high. However, survival is possible with rapid correction of hyperammonemia. As the clinical manifestations are non-specific, a high index of suspicion is necessary for the correct diagnosis and management.