• "Porphura" (Greek) = purple = urine colour during attack
  • Rare, hereditary (very rarely acquired) haem synthesis errors (porphyrins)
  • Acute or chronic
  • F>M (rare before puberty & after menopause)
  • Only 10% have recurrent attacks
  • Check FHx

Clinical (acute episode)

Neuro, psychiatric, cuteneous, visceral

  • Abdo pain (90%), usually colicky, ±diarrhoea, with soft abdomen
  • Myalgia / weakness (proximal>distal, UL>LL)
  • Autonomic dysfunction (sympathetic stimulation common)
  • Psychosis or other psychiatric presentations
  • Skin lesions (blistering) rare except in porphyria cutanea tarda
  • Hyponatraemia (± seizures) due to SIADH in 40%
  • Dark urine (on exposure to light)


  • Urine porphyrin studies (ask lab for collection details)
  • High ALA and PBG (during attack) very sensitive and specific
  • Stool porphyrin studies/ration (ask lab for details)
  • Other (erythrocyte, genetic) tests if ALA/PBG tests positive

Management (acute)

  • Analgesia
  • Withdraw triggering drugs (Barbiturates, Anticonvulsants, Progestins, Rifampin)
  • Give glucose (high carbohydrate intake). Start 10% dextrose infusion
  • Actively manage hyponatraemia (& ↓Mg++)
  • ↟BP/↟HR respond to Β-blockers
  • Haem arginate (donor IV haem) - ask haematology for advice
  • Avoid sunlight if cuteneous
  • PCT may later require phlebotomy to reduce liver iron stores

Content by Dr Rory O'Brien, Dr Íomhar O' Sullivan. Last review Dr ÍOS 12/04/22.