[A 25-year-old patient with colonic pseudo-obstruction, hyponatremia, hypertension, and diffuse pain]

A 25-year-old hypertensive patient presented to the Emergency Department with constipation and diffuse pain which had been increasing for 10 days. She had consulted several doctors before, but neither various analgesics nor metoclopramide had been beneficial. Blood analysis showed hyponatremia. A megacolon and polyneuropathy were found. Shortly after admission, she developed generalized seizures while hyponatremia increased compatible with SIADH (syndrome of inadequate ADH secretion). Urine examination revealed a markedly elevated excretion of porphyrins. Since porphobilinogen deaminase activity was clearly decreased, diagnosis of acute intermittent porphyria could be confirmed.

This case shows how definite diagnosis of this illness is often delayed because of its rarity and the variety of its possible symptoms and signs. This delay leads to a high risk of aggravating the disease by prescribing porphyrinogenic drugs.