Acute Intermittent Porphyria

Summary

  1. AIP is an acute porphyria known to cause abdominal pain, gastrointestinal issues, and neurological changes. 

  2. Symptoms usually begin to present after puberty.

  3. Acute attacks usually require hospitalisation and treatment by a porphyria specialist.

AIP is inherited from one of the parents and usually first manifests after puberty especially in girls. Severe abdominal pain with vomiting and constipation is the main feature but pain, numbness and weakness in the arms and legs can also be present as well as palpitations, confusion, agitation, seizures, hallucinations and insomnia. On blood tests sodium levels may be low.

Triggers include fasting, low carbohydrate intake, alcohol intake, infections and a whole range of drugs which are listed on porphyria websites and should be avoided. In women episodes may coincide with menstruation.

Management consists of avoiding these triggers and dealing urgently with acute attacks.

In acute attacks intravenous glucose and pain relief with opiates, usually morphine is required. If this does not settle the pain haemarginate infusions can result in rapid improvement and may be required on up to four consecutive days. Access to suitable veins is critical and haemarginate needs to be specially prepared and be given through a central line. 

In acute attacks prompt attendance at a hospital emergency department is critical so treatment can be given promptly to relieve symptoms and prevent deterioration.

 

Management Plans

Because treatment needs to be given promptly and is complex its best to always attend the same emergency department and to have an agreed treatment plan spelling out in some detail what needs to happen. This ideally should include the contact details of a porphyria specialist and be agreed to by the patient, the emergency department staff and the porphyria specialist.

Importantly other cause of abdominal pain including appendicitis, cholecystitis endometriosis and bowel inflammation can still occur and must not be overlooked

 

Testing

Its important to confirm the diagnosis of porphyria and to document this clearly in the patient records and plan.

The best time to prove the diagnosis is during an acute attack when levels of PBG and porphyrins, mostly uroporphyrin, are high in the urine. Urine PBG can be done quickly but porphyrin estimations are usually done in a specialised lab and take time.

 

In laboratory proven cases of AIP elevated urine PBG is confirmatory during acute attacks of AIP but if symptoms are typical treatment should commence promptly and not be delayed while waiting for the test result.

Click for more information about testing.