Acute Intermittent Porphyria: Causes, Symptoms, Diagnosis, Treatment, and Prevention
In acute intermittent porphyria (AIP), porphyrins and their precursors accumulate in the body as a result of deficiencies in enzymes involved in heme synthesis. The purpose of this blog post is to provide an overview of acute intermittent porphyria, including its causes, symptoms, diagnosis, treatment, and prevention.
Causes
The gene encoding porphobilinogen deaminase (PBGD), also known as hydroxymethylbilane synthase (HMBS), is mutated in acute intermittent porphyria. When PBGD is lacking, porphyrin precursors, such as delta-aminolevulinic acid (ALA) and porphobilinogen (PBG), accumulate, causing symptoms of AIP.
Symptoms
Acute intermittent porphyria may cause the following symptoms:
AIP is characterized by severe, colicky abdominal pain.
Patients may experience a variety of neurological symptoms, including peripheral neuropathy, muscle weakness, seizures, and psychiatric disturbances such as anxiety, depression, or hallucinations.
The autonomic nervous system may be involved in symptoms such as tachycardia, hypertension, constipation, and urinary retention.
When exposed to the sun, some individuals may experience skin manifestations such as photosensitivity, blistering, and hyperpigmentation.
Diagnosis
Medical history, physical examination, laboratory tests, and genetic testing can all be used to diagnose acute intermittent porphyria. Diagnostic assessments may include:
Blood and urine tests can detect elevated levels of porphyrins and their precursors, particularly ALA and PBG.
An enzyme assay can identify deficiencies in PBGD activity.
AIP can be diagnosed through DNA testing of the HMBS gene.
By temporarily lowering urinary ALA and PBG levels with intravenous administration of heme or glucose, provocative testing can confirm the diagnosis.
Treatment
In acute intermittent porphyria, treatment focuses on managing symptoms and preventing acute attacks.
The intravenous administration of heme is able to reduce porphyrin accumulation during acute attacks and alleviate symptoms.
Abdominal pain may be managed with anti-inflammatory drugs or opioids.
It may be necessary to inject intravenous fluids and provide glucose supplements during acute attacks to maintain hydration and energy levels.
In order to prevent acute attacks, patients should avoid known triggers such as certain medications, alcohol, fasting, and exposure to sunlight.
Prevention
Acute intermittent porphyria can be prevented by avoiding triggers and managing underlying factors. These include:
Medications that exacerbate porphyria symptoms, such as antibiotics, anticonvulsants, and hormones, should be avoided.
Acute attacks can be triggered by alcohol consumption, so it should be avoided or limited.
Patients should wear protective clothing, use sunscreen, and avoid prolonged exposure to sunlight.
To prevent complications and manage symptoms, patients with acute intermittent porphyria should receive regular medical monitoring.
