Acute intermittent porphyria
| Classification according to ICD-10 | |
|---|---|
| E80.2 | Other porphyria Acute intermittent porphyria |
| ICD-10 online (WHO version 2019) | |
The acute intermittent porphyria ( AIP ) is a form of porphyria . These are mostly congenital disorders of heme biosynthesis, in which an enzyme defect leads to overproduction, accumulation and increased excretion of intermediate products of heme synthesis, the so-called porphyrins . A distinction is made between erythropoietic (affecting blood formation) and hepatic (affecting the liver) porphyrias.
In addition to porphyria variegata (PV) and hereditary coproporphyria (HCP), AIP belongs to the acute hepatic porphyrias .
etiology
AIP is based on an autosomal dominant inherited defect of porphobilinogen deaminase (PBG deaminase), an enzyme in the metabolic pathway of heme synthesis. About 400 mutations of the PBG deaminase gene on chromosome 11 (gene locus 11q24.1-q24.2) are known.
Clinical manifestations
There are repeated attacks of colicky abdominal pain and severe neurological and psychiatric disorders. The disease is usually latent until exogenous or endogenous triggers trigger an acute attack.
trigger
- stress
- Dehydration (dehydration)
- Ethanol
- Starving
- Pharmaceuticals (barbiturates, benzodiazepines, anesthetics (etomidate, ketamine), pentazocine, meprobamate, glutethimide, phenytoin, corticosteroids, etc.)
- sepsis
- Thujone ( neurotoxin , ingredient of absinthe )
- female sex hormones
Symptoms of the acute flare
Acute abdominal pain is often the first and often the only sign of the disease. As a result, patients with AIP are often exposed to unnecessary appendectomy because the symptoms of the disease are similar to those of acute appendicitis .
In addition, various neurological and psychiatric disorders occur, such as motor weakness, weakened or lost muscle reflexes , disorders of the cranial nerve functions or the autonomic nervous system , up to delirium, psychoses, coma and convulsions.
Clinical significance of acute intermittent porphyria
The disease is particularly important for the anesthetist, as many of the triggering drugs play a role in anesthesia . Knowledge of the presence of this disease prior to induction of anesthesia is necessary so that an acute flare-up can be avoided (see below: Therapy). In principle, both general and regional anesthesia can be performed on patients with AIP , provided that the substance groups mentioned are not used.
Diagnosis
In the acute episode of AIP, the increased excretion of 5-aminolevulinic acid and porphobilinogen in the urine can be demonstrated.
The analysis of stool porphyrins can be used to distinguish it from other forms of acute porphyria. The diagnosis is confirmed by determining the PBG deaminase activity in the erythrocytes, although the large fluctuations in the activity of the enzyme are problematic. Molecular analysis of the gene defect is also possible, but even with proven gene carriers only around 10 to 20 percent of all AIP gene carriers appear to develop symptoms.
therapy
As with all genetic defects, no specific therapy is known. The aim is exposure prophylaxis , i.e. the avoidance of triggering factors. The symptomatic therapy of neurological and psychiatric disorders corresponds to that used for disorders of the same kind with a different cause (see there). The more pronounced the symptoms, the more urgent therapy is. In acute episodes, glucose infusions (20 g / h or 500 g / day) and hemin are used as drug therapy . Haemin ( trade name Normosang) should not be confused with haematin . Psychotherapy and physiotherapy have proven effective in containing long-term disorders.
Individual evidence
- ↑ Thomas Kia (Ed.): AllEx - Alles fürs Examen . 1st edition. Georg Thieme Verlag KG, 2012, ISBN 978-3-13-146951-9 , p. 345 .
- ↑ Petro E. Petrides: The acute intermittent porphyria . Dtsch Arztebl 1997; 94 (50): A-3407 / B-2761 / C-2487. Online version
