Acute intermittent porphyria

Background

  • Acute Intermittent Porphyria is a disorder caused by the inability to produce heme, a component of hemoglobin in red blood cells.
  • The defective enzyme is porphobilinogen deaminase.
  • Patients typically present with dark urine, abdominal pain, and psychiatric disturbances

Triggers

Clinical Features

  • Gastrointestinal symptoms
    • Acute abdominal pain (85-90% of attacks)
    • Port wine-colored urine
    • Agitation, confusion, combativeness, seizure

Differential Diagnosis

Extra-abdominal Sources of Abdominal pain

Evaluation

Consider porphyria in patients with abdominal pain that is unexplained after an initial workup has excluded common causes (appendicitis, cholecystitis, pancreatitis, etc).

  • Spot urinary porphobilinogen (sendout at most hospitals)
    • Normal = 0-4mg/day
    • acute attack, spot urine can be 20-200mg/L
  • Recurrent attacks in a patient with proven acute porphyria are usually similar and can be diagnosed on clinical grounds without biochemical reconfirmation.

Management

Disposition

See Also

References

Video