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Urea cycle disorders: a life-threatening yet treatable cause of metabolic encephalopathy in adults
  1. Nicholas F Blair1,
  2. Philip D Cremer1,
  3. Michel C Tchan2
  1. 1Department of Neurology, Royal North Shore Hospital, Sydney, Australia
  2. 2Adult Genetic Metabolic Disorders Service, Westmead Hospital, Sydney, Australia
  1. Correspondence to Dr Michel C Tchan, Department of Genetic Medicine, Westmead Hospital, Hawkesbury Road, Westmead NSW 2145, Australia; michel.tchan{at}


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.

  • Urea Cycle Disorders, Inborn
  • Ornithine Carbamoyltransferase Deficiency Disease
  • Hyperammonemia
  • Encephalopathies, Metabolic
  • Postpartum Period

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