Papilloedema in late-onset citrullinaemia: report of second case.

A young adult patient suddenly began to have episodes of unconsciousness that each lasted for several hours. Brief episodes of lethargy occurred monthly. Biochemical tests disclosed high levels of ammonia and citrulline in the serum. Brain oedema was suggested by CT scan, and optic disc swelling was observed ophthalmoscopically, indicating papilloedema. He died in coma. Deficient activity of argininosuccinate synthetase in the liver was demonstrated. Papilloedema was confirmed histologically. We believe that papilloedema is a serious sign indicating poor prognosis in late-onset citrullinaemia.