Acute Intermittent Porphyria

Prevalence: <200,000 cases of porphyria in USA, AIP: 5 to 10 in 100,000 worldwide.

Highest in Northern Europeans.

More commonly manifests in females, typically third to fourth decades of life.

Drugs and/or chemicals that induce heme containing hepatic CYP450 enzyme (e.g., barbiturates, estrogens, smoking, alcohol).

Induction of ALA synthase enzyme by fever or fasting.

Psychological stress.

Precipitation of acute crisis in periop period.

Diagnosis of latent AIP requires high index of suspicion in pts with unexplained acute abdominal pain and neuropsychiatric manifestations.

Potentially life threatening especially with delayed diagnosis.

Once diagnosed, all first-degree relatives should be screened.

One in eight inherited metabolic disorders of heme synthesis pathway is caused by mutations in the genes coding for each prospective enzyme in the pathway.

Autosomal dominant with incomplete penetrance.

Motor neuropathy, autonomic dysfunction, and psychiatric abnormalities.

Pts may be encountered for acute and chronic pain management.

Gene mutation causing deficiency in PBG deaminase enzyme

Accumulation of neurotoxic porphyrin precursors: ALA and PBG