What Is Acute Intermittent Porphyria?

Acute intermittent porphyria is a more common and severe form of porphyria. This disease is caused by excessive accumulation of -amino- ketovaleric acid (ALA) and porphylanogen in the body, and is clinically characterized by abdominal cramps, refractory constipation, mental symptoms, and excretion of large amounts of ALA in the urine and porphyrin original. This disease is an autosomal dominant genetic disease, and symptoms rarely occur during puberty. Most of them are 20 to 40 years old, and there are more women than men.

Basic Information

English name

acute intermittent porphyria

Visiting department

Gastroenterology

Multiple groups

Young women

Common causes

Autosomal dominant inheritance

Common symptoms

Abdominal cramps, refractory constipation, psychiatric symptoms, and a large amount of ALA and porphyrin excretion in the urine

Causes of acute intermittent porphyria

The disease is an autosomal dominant inheritance. The porphylanogen deaminase allele located on 11q24 is mutated, which causes the pathway of porphylanogen to urinary porphyrinogen being blocked, ALA and porphylanogen increase, and urine is excreted. Also increased. Because heme and its distal products are reduced, the normal feedback inhibition is weakened, and the activity of ALA synthetase is enhanced, which further increases ALA and porphyrin.

Clinical manifestations of acute intermittent porphyria

The disease usually develops in adulthood, and often has a long asymptomatic period, with periods of onset of days or months, and then an intermittent period, with inconsistent frequency and severity.

Abdominal pain

The most common symptom is acute abdominal pain. The location of the abdominal pain is uncertain. It can radiate to the back, bladder area, or external genitals around the umbilicus, upper or lower right, or even the entire abdomen. The onset of pain ranges from hours, days, and weeks, and can be accompanied by nausea, vomiting, and constipation. It is intermittent and spastic. May have mild fever and leukocytosis.

2. Nervous system symptoms

Peripheral neuropathy is also a major symptom, with varying severity, with myalgia, muscle weakness, and severe cases with convulsions and generalized paralysis. If the nerves are involved, ophthalmoplegia, optic nerve atrophy, facial nerve paralysis, hoarseness, Symptoms such as difficulty swallowing.

3. abnormal urine color

Fresh urine in the acute phase is brown or wine red, but it is also normal.

4. Mental symptoms

There are personality changes, neurasthenia, irritability, and rickets-like attacks.

Acute intermittent porphyria

Blood test

Acute episodes of white blood cells may increase slightly.

2. Urine routine

Porphylanogen increased significantly in urine and dark brown in onset. If the urine is acidified or placed in the sun, a large amount of porphyrinogen is transformed into uroporphyrin or fecal porphyrin, and the urine is purple-red.

3.X-ray inspection

Visible small intestine aeration or fluid level.

4. EEG

It is abnormal during the onset and presents a diffuse non-specific slow wave.

5. Qualitative test of dimethyl nitrogen benzaldehyde

It is a commonly used method for rapid detection of urinary porphyrin.

Diagnosis of acute intermittent porphyria

For recurrent and unexplained abdominal cramps, accompanied by neuropsychiatric symptoms, those who become brown after urine placement should consider this disease. Fresh urine can be used for qualitative tests of dimethyl benzaldehyde to confirm the diagnosis.

Acute intermittent porphyria treatment

Remove incentives

To eliminate the triggering factors, avoid using drugs that can enhance the effect of ALA synthetase, such as barbiturates, sulfa drugs, griseofulvin, chloroquine, and estrogen.

2. Diet therapy

Pay attention to carbohydrate and protein intake, and provide enough calories and electrolytes.

3. Symptomatic treatment

Abdominal intolerance is available for morphine. Chlorpromazine can relieve mental symptoms. Those who cannot eat can be treated with intravenous drip or complete parenteral nutrition.

4. Hemoglobin intravenous injection

Methemoglobin can reduce the levels of porphyrin and effectively relieve symptoms.