acute intermittent porphyria (AIP)

introduction

an autosomal dominant type of porphyria affecting porphobilinogen-deaminase
acute attacks may cause:
- psychiatric or CNS symptoms (eg. hysteria, depression, seizures, cortical blindness, coma)
- peripheral neuropathies (mainly motor and may mimic GBS)
- autonomic dysfunction and autonomic neuropathy (causing hypertension, tachycardia, constipation, abdominal pain - usually severe, colicky, epigastric pain that lasts for a few days, vomiting, etc)
- but no rash as with other porphyrias
patients with acute attacks always have elevations of porphobilinogen and amino-levulinic acid (ALA)
10-50 cases per million in USA
20x higher in northern Sweden
only 1-2% develop symptomatic attacks
most symptomatic patients are young adults 18-40 yrs old
attacks may be precipitated by use of “inducers” such as hypoglycaemia, barbiturates, oestrogens, sulphonamides, ethanol (alcohol and alcohol withdrawal) - see http://www.uq.edu.au/porphyria