Diagnosis and Management of Acute Intermittent Porphyria

Diagnostic Criteria

The American Association for the Study of Liver Diseases recommends ordering a spot urine sample for quantitative porphobilinogen (PBG) and delta-aminolevulinic acid (ALA), normalized to creatinine, as the essential first-line test when AIP is suspected, which confirms or excludes the diagnosis during symptomatic episodes 1, 2
Suspect AIP in patients presenting with recurrent severe abdominal pain without identifiable cause, especially in women aged 15-50 years 3
Neuropsychiatric manifestations, including peripheral neuropathy, autonomic dysfunction, mental status changes, or seizures, are indicative of AIP 4
Hyponatremia, which occurs in 25-60% of acute attacks, is a common finding in AIP patients 2, 3
Symptoms triggered by specific medications, fasting, alcohol, stress, or hormonal changes are characteristic of AIP 4, 5

Collect a random spot urine sample for quantitative PBG and ALA measurement during symptomatic episodes, as PBG >10 mg/g creatinine confirms acute hepatic porphyria 1, 2
Normal urine PBG during symptomatic episodes effectively excludes AIP as the cause of current symptoms 2, 3
Protect all samples from light by wrapping tubes in aluminum foil to prevent photodegradation of porphyrins, and refrigerate or freeze samples promptly, as PBG degrades within 24 hours at room temperature 6, 2

Perform gene sequencing of HMBS to confirm AIP and identify the specific mutation, as genetic testing identifies 95-99% of cases when whole-gene sequencing is performed 1, 2
Do not use genetic testing as first-line screening, as most mutation carriers (>90%) never develop symptomatic disease—penetrance is only ~1% in unselected carriers 4, 5

Obtain complete blood count and ferritin, comprehensive metabolic panel, liver enzymes, creatinine, and estimated glomerular filtration rate (eGFR) as baseline tests after diagnosis 1, 4, 2
Liver ultrasound and alpha-fetoprotein every 6 months after age 50 for hepatocellular carcinoma screening are recommended 1

The American Association for the Study of Liver Diseases classifies AIP patients into four subgroups that determine follow-up frequency: latent genetic carriers, asymptomatic high excretors, sporadic attack patients, and recurrent attack patients 4, 3
All confirmed AIP patients require at least annual monitoring, including liver enzymes, creatinine, and eGFR 4, 3

For moderate to severe attacks, immediate hemin treatment is recommended, with a dose of 3-4 mg/kg/day IV for 3-14 days, and clinical benefit depends on prompt administration—symptom relief typically requires 48-72 hours 5
For mild attacks, a trial of glucose therapy (approximately 300 g/day IV carbohydrate loading) is recommended while awaiting hemin or if hemin is unavailable 5