Acute Intermittent Porphyria: Trigger

Advanced, Organ-Based and Clinical Sciences

Attacks are episodic and typically triggered by inciting factors such as medications, drastic diets/fasting, or stress such as an infection or surgery.

Most notably in the practice of anesthesia, barbiturates and other CYP inducers can trigger AIP attacks. Barbiturates lead to increased levels of porphyrin by stimulating aminolevulinic acid (ALA) synthetase. These intermediaries in the heme synthesis pathway then build-up and precipitate an attack. Glucose acts to suppress ALA synthetase and thus is useful in prevention and treatment. Other known triggers include diazepam, sulfonamides, griseofulvin, sex hormones e.g. in contraceptives, glucocorticoids, phenytoin, cigarette smoke, and anti-retrovirals used to treat HIV.

Other common anesthetic agents such as propofol and fentanyl appear to be safe in this population, as do etomidate and ketamine although the latter are potential triggers in animal studies.

Although autosomal dominant, most patients have no family history of the disease as acute attacks only occur in about 10% of carriers, most commonly affecting young adult women.

Sources

    J Cardiothorac Vasc Anesth;2018 Dec;32(6):2716-2720

    [PubMed: 29306617]

    Anaesthesia. 1993 May;48(5):417-21

    [PubMed: 8250166]

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Answered correctly

2019

Year asked

Author
Matt Thames, MD