We describe for the first time an association between rectal motility disorder and acute intermittent porphyria (AIP) in one patient. Abnormal haeme metabolism appears to play a pivotal role in the pathogenesis of these disorders.

A 20 year old male was admitted urgently with severe abdominal pain of eight days’ duration, distension, constipation, faecal vomiting, and general malaise. The attack was preceded by severe upper respiratory infection. His medical history included constipation and encopresis since early childhood. At age 15 years he had been hospitalised for abdominal pain, constipation, and vomiting, and was investigated for the possibility of Hirschsprung’s disease (HD) which was excluded after normal rectal mucosal biopsy. Under a diagnosis of habitual constipation, the patient was referred for …