Acute intermittent porphyria

Notes

## Basic introduction

  • Acute intermittent porphyrias (AIP) are disorders, inherited or acquired, in which there is deficiency of enzymes, such as porphobilinogen deaminase, in the heme bio-synthetic pathway
  • This leads to the accumulation of delta-aminolevulinic acid (ALA) and porphobilinogen (PBG) which are precursors of heme synthesis in the liver
  • Pain due to AIP is neuropathic (without inflammation)

## Statistics[b]

  • Global prevalence of AIP is 50-100 people per million.
Symptoms
  • Mainly asymptomatic
  • Attacks develop over two or more days
  • Abdominal pain (that is often severe)
  • Nausea
  • Vomiting
  • Constipation
  • Hypertension
  • Muscle weakness
  • Pain in the back, arms and legs
  • Palpitation
  • Urinary retention
  • Confusion
  • Hallucinations
  • Seizures
  • Electrolyte imbalance
Diagnosis
  • Pink or red urine after exposure to sunshine
  • Delta-ALA and PBG
  • The diagnosis is confirmed by the identification of a causal mutation of the HMBS gene (specifically PBGD gene in chromosome 11q23.3)
Differential
  • Abdominal Hernias
  • Acute Gastritis
  • Acute Mesenteric Ischemia
  • Acute Pancreatitis
  • Acute Pyelonephritis
  • Amebic Liver/Hepatic Abscesses
  • Aortic Dissection
  • Appendicitis
  • Biliary Disease
  • Chester Porphyria
  • Cholecystitis
  • Abdominal Abscess
  • Abdominal Angina
  • Chronic Pelvic Pain in Women
  • Colonic Obstruction
  • Constipation
  • Delta-aminolevulinate dehydratase deficiency porphyria
  • Diverticulitis
  • Cholecystitis
  • Guillain-Barré syndrome
  • Hereditary coproporphyria
  • Endometriosis
  • Adrenal Carcinoma
  • Esophagitis
  • Epilepsy
  • Cholelithiasis
  • Adrenal Crisis
  • Portal Vein Obstruction
  • Hypertension
  • Ovarian Cysts
  • Pelvic Inflammatory Disease
  • Rehabilitation
  • Variegate porphyria
Prevention
  • Genetic counselling
Reference

a. Periasamy, V., Al Shubaili, A., & Girsh, Y. (2002). Diagnostic Dilemmas in Acute Intermittent Porphyria. Medical Principles and Practice, 11(2), 108-111.

b. Ramanujam VM, Anderson KE; Porphyria Diagnos-tics-Part 1: A Brief Overview of the Porphyrias. Curr Protoc Hum Genet. 2015 Jul 1 86:17.20

c. Besur, S., Hou, W., Schmeltzer, P., & Bonkovsky, H. L. (2014). Clinically important features of porphyrin and heme metabolism and the porphyrias. Metabolites, 4(4), 977-1006.

Management
  • It is mainly symptomatic and include;
  • Glucose 10% (it inhibits heme synthesis)
  • Hemin injection (when available)
  • Relief of pain e.g. by using opiates
  • High-carbohydrate diet
  • Discontinuation of precipitating factors such as drugs:

||| Analgesics

||| Antiemetics

||| Hematin

||| Heme arginate

||| Selected antiepileptics such gabapentin [avoid barbiturates] to control seizure.

  • Crippling attacks may require hepatic transplant
  • Rehabilitation program
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