Ornithine transcarbamylase deficiency presenting as encephalopathy during adulthood following bariatric surgery.

BACKGROUND Neurological complications following bariatric surgery are rare. Whereas nutritional deficiencies are the most common cause of neurological symptoms, the unmasking of previously subclinical metabolic disorders can also lead to significant morbidity. OBJECTIVE To characterize the clinical presentation, serum biochemical fluctuations, and functional enzymatic analysis of a case of functional ornithine transcarbamylase deficiency unmasked by a dietary change following bariatric surgery. DESIGN Case report. SETTING Tertiary referral center, hospital (inpatient) setting. PATIENT A 29-year-old woman who presented with intermittent encephalopathy associated with recurrent hyperammonemia. INTERVENTIONS Clinical, biochemical, and mutational studies. RESULTS The pattern of intermittent hyperammonemia and encephalopathy following oral and parenteral nutrition suggested a urea cycle abnormality. Functional enzymatic assay results showed markedly reduced ornithine transcarbamylase activity in the absence of known coding mutations. CONCLUSION Previously asymptomatic ornithine transcarbamylase deficiency should be suspected in adult patients who develop recurrent hyperammonemia and encephalopathy following bariatric surgery.