Abstract

Urea cycle disorders are inborn errors of metabolism that, in rare cases, can present for the first time in adulthood. We report a perplexing presentation in a woman 4 days postpartum of bizarre and out-of-character behaviour interspersed with periods of complete normality. Without any focal neurological signs or abnormality on initial investigations, the diagnosis became clear with the finding of a significantly elevated plasma ammonia level, just as she began to deteriorate rapidly. She improved following intravenous dextrose and lipid emulsion, together with sodium benzoate, arginine and a protein-restricted diet. She remains well 12 months later with no permanent sequelae. Whilst this is a rare presentation of an uncommon disease, it is a treatable disorder and its early diagnosis can prevent a fatal outcome.