[Use of propofol in a patient with acute intermittent porphyria]

Anesthetic considerations in porphyrias

Four hereditary types of porphyria are now classified as acute porphyrias. Enzymatic defects result in accumulation of porphyrin precursors (usually ALA and PGB). The quantity of these precursors may be normal or slightly increased in latent periods but increase to toxic levels during a porphyric crisis. Iatrogenic induction of ALA synthetase by administration of certain triggers (classically barbiturates) is only one of several factors which contribute to porphyric crisis. Signs and symptoms of acute porphyric attack consist primarily of neurologic dysfunction, which occurs secondary to neurotoxicity of ALA or diminished intraneuronal heme levels. Appropriate anesthetic management of porphyria requires knowledge of the type of porphyria (acute vs non-acute), assessment of latent versus active (crisis) phase, awareness of clinical features of porphyric attack, and knowledge of safe pharmacologic intervention.

Elevated porphyrins following propofol anaesthesia in acute intermittent porphyria

A patient with acute intermittent porphyria was anaesthetised with propofol for a minor orthopaedic procedure. Postoperative urinary porphyrins were markedly raised compared to pre-operative values, although the patient remained clinically well. Caution should continue to be exercised when propofol is used in patients with acute porphyrias.

[Acute hepatic porphyria and Diprivan]

Propofol may be used without any restriction in all cases of asymptomatic hepatic porphyria, as a bolus injection for induction and maintenance of anaesthesia and as a continuous infusion to produce anaesthesia of short and medium duration. If in doubt as to the absolute safety of propofol in case of symptomatic hepatic porphyria, preference has to be given to neuroleptanalgesia, benzodiazepines and muscle relaxants. If propofol is to be used, treatment with haematin should be readily available. In all cases, it is essential to determine porphyrins and their precursors prior to and after surgery. Urine collection should strictly adhere to the recommended procedure: sterile conditions, protected from light and high temperature. Any abnormal reaction after the administration of a drug, especially propofol, should be notified to and discussed with the National Porphyria Centre (Centre Français des Porphyries). In case of symptomatic hepatic porphyria the use of propofol should always be notified to the National and to the European Porphyria Centres (Orphan Europe).