An 18-year-old female presenting with seizures, myalgias, abdominal pain, headache and vomiting had multiple large contrast-enhancing white matter lesions on MRI and was diagnosed with acute intermittent porphyria (AIP), in a report from the Department of Neurology, Mayo Clinic, Rochester, MN. She was febrile, confused, complained of visual hallucinations, and had increased blood pressure and tachycardia. Liver enzymes were elevated and electrolytes lowered. AIP was considered because of seizures, dysautonomia, and abdominal pain. Uroporphyrin levels were 2,186 mcg/24 hrs (normal, 3-25), and porphobilinogen, 312.8 mg/24 hrs (normal, 0-0.5). Urine was dark, resembling ale or tea. Fecal porphyrin profile excluded hereditary coproporphyria and variegate porphyria. One week after treatment with IV hematin and dextrose, MRI lesions resolved. 
COMMENT. AIP is an autosomal dominant disorder caused by a genetic deficiency of PBG deaminase enzyme involved in heme synthesis. Most patients are asymptomatic, but under stress, during menstruation, surgery, fasting or exposure to drugs, an acute attack may occur, with heme precursors, aminolevulinic acid and PBG, excreted in the urine. Treatment with barbiturates will aggravate or precipitate an attack. Episodes present with abdominal pain, vomiting, seizures, neuropathy, dysautonomia, and psychiatric symptoms. Encephalopathy, a presenting symptom in the above case, is unusual, but combined with abdominal pain, should arouse suspicion of AIP. A more common variety of porphyria in childhood is congenital erythropoietic porphyria, presenting with cutaneous photosensitivity and hemolytic anemia, but no neurologic symptoms.