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how to diagnose and differentiate porphyria-porphyria is easily confused

how to diagnose and differentiate porphyria-porphyria is easily confused

Differential diagnosis of porphyria

It should be distinguished from the following diseases:

1. Delayed cutaneous porphyria

Autosomal dominant hereditary diseases, more male than female, more onset after 40 years old. There is a deficiency of uroporphyrin decarboxylase in liver, and there may be a deficiency of uroporphyrin synthase. Urine has more urinary porphyrin excretion, making urine red, and light sensitive phenomenon, causing skin damage. Most patients are accompanied by liver diseases, but the relationship between liver diseases and increased uroporphyrin is still unknown. Urine uroporphyrin, especially uroporphyrin, increased obviously. Cocoporphyrin in urine can be slightly increased. Care should be taken to protect the skin during treatment. Repeated venous bloodletting in patients with excessive iron load in liver can reduce iron storage in liver and improve symptoms. Alcoholics must give up drinking. Chloroquine can be taken to combine with uroporphyrin in liver to form a water-soluble substance to promote its excretion from urine.

Second, acute intermittent porphyria

More common, autosomal dominant inheritance. Asymptomatic recessive patients can be found in families. Both sexes can suffer from it, and the onset age is mostly 20 ~ 40 years old. Uroporphyrinogen synthase was deficient in liver, and the amount of porphyrinogen converted into uroporphyrinogen decreased. Therefore, heme synthesis is obstructed, the feedback inhibition of heme on ALA synthase is weakened, and the activity of ALA synthase is enhanced. As a result, ALA and porphyrin are synthesized excessively, and the excretion in urine is obviously increased. Typically, the urine is brown, but the urine color can also be normal. When this colorless urine is placed in sunlight, the urine will be dark red or brown because porphyrin and porphyrin change into porphyrin. Porphyrin and dimethylaminobenzaldehyde can show red reaction, which is called porphyrin original test (Watson-Schwartz test), which is used to diagnose the disease. Urine porphyrin and ALA can also be determined quantitatively. Clinical manifestations are characterized by neurological symptoms. It often shows acute paroxysmal abdominal pain, but there is no positive finding in abdominal examination, which is easy to be misdiagnosed as neurosis or hysteria. Others were misdiagnosed as acute abdomen because of abdominal distension, vomiting, constipation, low fever and leukocytosis. There can also be muscle pain, myasthenia and even paralysis. Some patients have mental symptoms such as personality changes, moodiness and hallucinations. Sinus tachycardia is common, which is related to vagus nerve damage. The treatment is mainly supportive therapy and symptomatic treatment during attack. Because barbiturates, phenytoin sodium, anesthetics, estrogens, contraceptives, sulfonamides, griseofulvin, etc. can enhance the role of ALA synthetase, it must be banned. Chlorpromazine and chloral hydrate can be used for abdominal pain. People with mental mania can try reserpine and perphenazine. If the attack is related to menstruation, androgen can be taken orally to prevent the attack.

III. Mixed porphyria

There are neurological manifestations similar to acute intermittent porphyria and skin lesions, which indicate that there are not only excessive ALA and porphyrin production in vivo, but also excessive photosensitive porphyrins. The pathogenesis is unknown. It may be related to the increase of ALA synthase activity in liver, or it may be caused by the defect of protoporphyrinogen oxidase. The excretion of a large amount of coproporphyrin and protoporphyrin in patients' feces, and the increase of ALA and porphyrin in urine during acute attack. The treatment is the same as acute intermittent porphyria. In addition, care should be taken to protect the skin.

IV. Hereditary Cocoporphyria

The clinical manifestations are similar to mixed porphyria. Although a large amount of coproporphyrin is excreted in feces, the content of protoporphyrin is normal or slightly increased. The disease may be caused by the deficiency of coccoporphyrinogen oxidase. The treatment principle is the same as mixed porphyria.

V. Acquired porphyria

Also known as symptomatic porphyria. It is common in lead poisoning and hexachlorobenzene poisoning. Because of inhibition of heme synthase in lead poisoning, the concentration of protoporphyrin in red blood cells increased, but its protoporphyrin combined with globulin firmly, and it was difficult to enter plasma through red blood cells, so the light sensitivity phenomenon was not obvious. BHC poisoning can cause the decrease of urinary porphyrinogen decarboxylase activity, so it can appear similar clinical manifestations to delayed cutaneous porphyria.

VI. Hepatoerythropoietic porphyria

It is a rare and often severe autosomal recessive porphyria caused by the deficiency of urinary porphyrinogen decarboxylase. UPDC deficiency can occur in all tissues and is easily confirmed in red blood cells. The symptoms of cases with more residual enzyme activity were not serious.

Up to now, less than 20 cases of hepatoerythropoietic porphyria (HEP) have been reported all over the world. Skin blisters, red urine and anemia are common. Medical Education Network, collected. Although the clinical features of HEP are similar to those of congenital erythroblast porphyria, the distribution of porphyrin accumulation is different.

Diagnostic characteristics

Include an increase in isopherphyrin in feces or urine and zinc porphyrin in erythrocytes. Bloodletting is effective for mild HEP. Treatment of severe cases is similar to congenital erythropoietic porphyria.


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