Hematoporphyria

Introduction

Introduction to hematoporphyria

Hematoporosis (hematoporphyria), formerly known as purple disease, is a rare disease, mostly caused by genetic defects caused by the lack of enzymes involved in the heme synthesis pathway leading to porphyrin metabolism disorders. The clinical manifestations are mainly light-sensitive skin lesions, abdominal pain and neuropsychiatric symptoms. Porphyrin precursors may be the material basis for abdominal and neuropsychiatric symptoms. The sympathetic nervous system plays a role in the pathogenesis of abdominal pain and increased blood pressure. According to the site of porphyrin metabolism disorder, it is divided into erythropoietic hematoporphyria and hepatic porphyria.

basic knowledge

The proportion of illness: the incidence rate is about 0.0001% - 0.0002%

Susceptible people: no specific population

Mode of infection: non-infectious

Complications: urticaria, high blood pressure, erythema

Pathogen

Cause of hematoporphyria

Genetic factors (85%):

Acute intermittent hematoporphyria is more common and is an autosomal dominant genetic disease caused by a deficiency of PBG deaminase (urinary porphyrinogen synthase), which causes the transformation of intrahepatic PBG into uroporphyrinogen III. The decrease in the heme synthesis disorder caused by this enhances the action of ALA synthase, and as a result, the synthesis of ALA and PBG is increased and the discharge from the urine is increased.

Pathogenesis:

Metabolic disorder of porphyrin leads to abnormal porphyrin synthesis and increased production and excretion of porphyrin and its precursors including -aminolevulinic acid (ALA) and bilirubin (PBG), which is the only endogenous photoinduced light in human body. The sensitizer has a special absorption spectrum, which is most obvious at a wavelength of 405 nm. The porphyrin and its derivatives are activated to emit red fluorescence, which destroys the skin lysosome and causes photoreceptive skin damage. The strongest, the original porphyrin and coproporphyrin followed, while ALA and PBG have no photo-sensing, normal people's sunburn wave is 280-320nm, and patients with increased porphyrin in the body can still occur after using glass filter to remove sunburn. Light sensitive skin damage.

Porphyrins are mainly synthesized in red bone marrow and liver. According to the site of porphyrin metabolism disorder, hematoporphyria is divided into two types: erythropoietic hematoporphyria and hepatic porphyria. Heme synthesis The lack of different enzymes leads to different types of hematoporphyria. As shown in Figure 1, erythropoietic hematoporphyria, also known as myeloid hematoporphyria, is caused by a disorder of porphyrin metabolism in the bone marrow, depending on the porphyrin produced. Also divided into: 1 protoporphyrin type; 2 urinary porphyrin type; 3 fecal porphyrin type, hepatic porphyria caused by intrahepatic porphyrin metabolism disorder, divided into 4 subtypes: acute intermittent porphyrin Disease; delayed cutaneous porphyria; mixed porphyria; hereditary fecal porphyria.

Prevention

Hematoporphyria prevention

1. Avoid inducement should not take a variety of drugs that cause symptomatic porphyrinuria. Avoid excessive fatigue, mental stimulation and hunger, alcohol, infection and other incentives to reduce the onset of the disease.

2. Dietary sugars have the effect of inhibiting ALA synthase, so high glucose intake is quite effective in preventing and treating the onset of most cases. In acute attacks, 10% to 25% glucose or fructose at a rate of 10 to 15 g/h, intravenous infusion for 24 hours with a high-glucose diet can quickly relieve symptoms.

Complication

Hematoporphyria complications Complications, urticaria, hypertension, erythema

1, skin symptoms: more in infancy, but also in adults (late skin porphyria), mainly caused by light, the most susceptible to light waves is 405nm, can penetrate the glass window, exposed to the skin Departments such as the amount, nose, ears, neck, hands and other places appear erythema, and then become herpes, and even ulceration, often left scar after scarring, causing deformity and pigmentation, rash may be eczema, urticaria, summer pruritus or more Types of erythema, oral mucosa can have red spots, teeth are brownish red, and can also cause eye damage such as conjunctivitis, keratitis and iritis, some patients are not only sensitive to skin, there may be atrophy in the later stage of inflammation, melanin And similar to scleroderma or dermatomyositis, severe cases can be deformed by the formation of scars on the nose, ears, fingers, skin, patients can have a special purple face, in erythropoietic hematoporphyria and delayed skin type , can have hirsutism.

2, lower limb pain, feeling abnormal.

3, spinal neuropathy, paraplegia or quadriplegia.

4, brain lesions, produce nerves, mental, autonomic symptoms, such as abdominal pain, high blood pressure and so on.

Symptom

Symptoms of hematoporphyria common symptoms constipation light sensitive skin damage irritability nausea bloating abdominal pain weakness low blood pressure low heat tension

The patient mainly showed intermittent abdominal pain, neuropsychiatric symptoms and tachycardia. Since the porphyrin in the patient did not increase, there was no photoreceptive skin damage.

(1) Skin symptoms:

In infants, it can also occur in adults (late skin porphyria). After exposure to light, erythema, herpes, and even ulceration appear on the exposed parts of the skin. Scars are left behind after scarring, causing deformity and pigmentation. The rash can be For eczema, urticaria, summer pruritus or erythema multiforme, oral mucosa may have red spots, teeth are brownish red, and concurrent eye damage such as conjunctivitis, keratitis and iritis, some patients with skin allergies Atrophy, melanin deposition and similar scleroderma or dermatomyositis, severe cases may have nasal, ear, finger skin scarring, may have a special purple face, erythropoietic hematoporphyria and delayed skin type, There may be hirsutism, hepatic porphyria, in addition to skin symptoms, may be accompanied by abdominal or neuropsychiatric symptoms at the same time or in the course of the disease, that is, mixed type.

(2) Abdominal symptoms:

Abdominal pain is the most important and prominent symptom. The paroxysmal cramps are sometimes extremely light, but most of them are more serious and even unbearable. The painful part can be limited, and it can spread to the whole abdomen or radiate to the back or waist. Accompanied by nausea, vomiting, and often intractable constipation. When examined, most of the abdomen did not have obvious tenderness. Except for slightly flatulence, few positive findings were found. Therefore, many cases were misdiagnosed as neurosis, snoring, and some patients. Constipation, bloating, vomiting, low fever, leukocytosis and increased heart rate were misdiagnosed as acute abdomen.

(3) Neuropsychiatric symptoms:

Symptoms of the nervous system are diverse, such as neuralgia of the extremities, hypoalgesia or numbness, and the disappearance of pain is rare. There may be muscle weakness in the limbs until the limbs are loose, and there may be muscle pain before or at the same time. It is a calf, tendon reflexes often decrease or disappear, abdominal, intercostal or diaphragmatic weakness can cause respiratory paralysis and life-threatening, as well as optic atrophy, ophthalmoplegia, facial nerve spasm, difficulty swallowing and vocal cord paralysis.

Many patients often have nervousness, irritability, irritability, and even hallucinations before an acute attack. Individual patients may be temporarily blind. In severe cases, convulsions may occur, and even coma may occur. EEG may occur in epileptic seizures or electrolyte-like disorders. Changes, may have low fever, sweating, normal or elevated blood pressure, or orthostatic hypotension, tachycardia occurs every time, especially when neuropsychiatric symptoms occur, disappear when relieved, so it can be used as this type of activity Indications.

Auxiliary inspection :

The most important basis for diagnosing the disease is the presence of a large amount of ALA and PBG in the urine. The urine color just solved is mostly normal, but if the urine is placed in direct sunlight, the urine gradually turns dark red or even black. It is the result of PBG being converted into red urinary porphyrin and bilirubin under the action of light. The urinary porphyrin produced has a special spectrum, which emits red fluorescence under ultraviolet irradiation, such as turning the urine into strong acidity and boiling. At 30 minutes, the urine color quickly turned dark red or brownish red.

The disease is relatively rare, easy to be ignored, the cause of unexplained abdominal pain must consider the possibility of acute intermittent porphyria, unexplained neurological disorders, especially peripheral nerve symptoms, local muscle weakness, relaxation sputum, etc., neuropsychiatric or The psychiatric illness is aggravated by taking barbiturate, or with menstrual cramps, or when taking female hormones or birth control pills, the authors suspect the possibility of porphyria.

Examine

Examination of hematoporphyria

1. Urine test: urine is often red (also colorless), but turns red after exposure to sunlight or acidification for half an hour.

2. Dimethylaminobenzaldehyde test (Watson-Schwartz test): It is a simple and reliable method to check PBG. PBG reacts with dimethylaminobenzaldehyde (Ehrlich aldehyde reagent) to become deep red, urinary biliary or and this reagent also produce red, but after the two substances are shaken with chloroform or butanol, the red is removed by this solvent, and the red color of PBG is still in the water layer. This test is often used when the disease is acute. Strong positive reaction; usually positive during remission, but sometimes negative; recessive cases The result of this test is weak positive or negative.

3. Chromatography: The most reliable diagnostic basis is the determination of ALA and PBG in urine by chromatography. Especially for intermittent and recessive cases, in the acute attack period, PBG excretion is 50 ~ 200mg / d (normal range is 0 ~ 4mg / d), ALA excretion is 20 ~ 100mg / d (normal range is 0 ~ 7mg/d), ALA and PBG measurements often decrease with the improvement of clinical symptoms. In the case of episodes, if the positive result of the dimethylaminobenzaldehyde test can be obtained in clinical work, the diagnosis can be established.

According to the condition, choose ECG, EEG and Abdominal B ultrasound.

Diagnosis

Diagnosis and diagnosis of hematoporphyria

Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.

Differential diagnosis

1. Acute abdomen: acute intermittent abdominal pain, often misdiagnosed as a variety of acute abdomen, and even laparotomy, but acute abdomen such as acute appendicitis, cholecystitis, pancreatitis, intestinal obstruction, renal colic, etc. The clinical features of the abdomen have fixed tenderness and rebound tenderness, muscle tension and other signs, urine exposure, red color after acidification, PBG test negative.

2. Lead poisoning: lead poisoning can cause porphyrin metabolism disorder and abdominal cramps, similar to acute intermittent type of seizures. Lead poisoning patients have a clear history of lead exposure, blood and urine lead levels are increased, although urinary - ALA and fecal porphyrin increased, but PBG was normal.

3. Symptomatic porphyrin urine: also known as acquired porphyria, porphyrin urine refers to excessive porphyrin excretion in the urine, these porphyrin substances do not produce the symptoms of the above various porphyria diseases, so porphyrin urine Not porphyria, symptomatic porphyrin urine is mainly fecal porphyrin, urinary porphyrin is not significant, porphyrin precursor is not increased, urine PBG test is negative, and various drugs such as barbiturates, Grummet, A Alanine, chlordiazepoxide, sulfonamides, tolbutamide, chlorpropamide, phenytoin, benzyl sulphonate, imipramine, ergot preparation, griseofulvin and chloramphenicol; lead, arsenic, gold , carbon tetrachloride, alcohol, phosphorus, selenium, benzene and other poisoning; liver disease, connective tissue disease, a variety of blood diseases can cause symptomatic porphyrin urine, in addition, fecal porphyrin in the feces, urinary porphyrin can also From food, gastrointestinal bleeding, etc., so if the content is below 200g / g dry manure is normal, it does not make sense for the diagnosis.

4. Skin type should be differentiated from pellagra.

5. The spirit of expression, when the group of neurological symptoms should be differentiated from encephalitis, polio, and schizophrenia.

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