hereditary hemochromatosis
Introduction
Introduction to hereditary hemochromatosis Hereditary hemochromatosis is a hereditary disease with abnormal iron metabolism. There are six different genotypes. The main one is related to the HFE gene. The other five are rare types of different genes, the main one of which is related to the HFE gene. Related, the other five are rare types, which are characterized by excessive iron absorption leading to destruction of different tissues and organs. basic knowledge The proportion of illness: 0.0006% Susceptible people: no special people Mode of infection: non-infectious Complications: cirrhosis, diabetes, arrhythmia, heart failure, arthritis, abdominal pain
Cause
Cause of hereditary hemochromatosis
Abnormal regulation of iron absorption (40%):
Found in idiopathic hemochromatosis, the patient's small intestine mucosa has a genetic defect in the regulation of iron absorption. The amount of iron absorbed from food is more than normal. It absorbs 2 to 4 mg per day (normally 1 mg), and it is accumulated over several months. Ten years later, the accumulated iron in the organization can reach 15 to 50 g, which exceeds the total amount of stored iron in normal human tissues.
Erythropoiesis (30%):
Erythropoiesis causes anemia, which in turn increases the iron absorption of the intestines significantly, exceeding the actual needs of the body, causing excessive iron deposition in the tissue. This condition is called erythropoietic hemochromatosis.
Liver disease (15%):
Hemochromatosis can occur in chronic liver disease, the cause is multifaceted, including the regulation of iron absorption in the intestinal mucosa, resulting in increased iron absorption; chronic liver disease can occur due to unexplained erythropoiesis and secondary anemia, resulting in increased iron absorption Some patients with liver disease are addicted to alcohol. Some alcoholic beverages contain extremely high levels of iron, and alcohol can also stimulate iron absorption.
Excessive iron content in food (5%):
The Bantu people in southern Africa are used to cooking and brewing iron. Therefore, the iron content in food and wine is very high, up to 100mg per day. The intestinal absorption of iron in the patient's intestine is normal, because the concentration of iron in the intestine is too high. As a result, more iron is dispersed into the intestinal mucosa cells and absorbed, maintaining a positive balance of iron 2 to 3 mg, making the iron overload too heavy, and hemochromatosis can occur after middle age.
Long-term multiple blood transfusions (5%):
Every 100ml of normal blood contains about 50mg of iron, patients with aplastic anemia, severe -globin-producing anemia or iron granulocyte anemia, repeated blood transfusions due to the condition, if the total blood transfusion exceeds 10,000 When ml is used, a large amount of iron can be introduced into the body and deposited in the tissue.
Prevention
Hereditary hemochromatosis prevention
The disease is a hereditary disease, and the main preventive measures at present are to strengthen prenatal care and reduce the birth of the child.
Complication
Hereditary hemochromatosis complications Complications cirrhosis diabetes arrhythmia heart failure arthritis abdominal pain
Common complications:
1. Hepatocyte dysfunction, cirrhosis, skin pigmentation, diabetes (concurrency rate 50% to 60%);
2. Cardiac disease with cardiac hypertrophy, heart failure, arrhythmia, and conduction block as clinical manifestations;
3. Pituitary failure is common and can lead to testicular atrophy and loss of libido;
4. Abdominal pain;
5. Arthritis;
6. Cartilage Calcium.
Symptom
Hereditary hemochromatosis symptoms common symptoms fatigue joint pain diabetes hepatomegaly
There is fatigue, arthritis, liver enlargement, skin pigmentation, diabetes, and gradually develop into cirrhosis and cancer.
Examine
Examination of hereditary hemochromatosis
1 blood and bone marrow: blood and bone marrow without obvious specificity, bone marrow smear or section, iron staining treatment showed increased extracellular iron, but no decisive significance for diagnosis.
2 blood biochemical examination: serum iron, serum iron saturation and serum ferritin determination can be used as a screening test for this disease, serum iron often increased to more than 200g / dl, an average of 250g / dl; serum iron saturation up to 80 ~ 100%; serum ferritin concentration can also be significantly increased.
3 Deferoxamine test: Deferoxamide is an iron chelator. After intramuscular injection at 10g/ml, the iron in the urine of normal people is <2mg in 24 hours, and the discharge of patients with hemochromatosis is often >10mg. This test reflects the iron content of the main cells in the body.
4 Liver biopsy: In the sections of liver tissue, the proliferation of fibrous connective tissue containing a large amount of hemosiderin and different degrees of severity in the main cells, and even the cirrhosis of the giant nodules, the highest diagnostic value.
Diagnosis
Diagnosis and identification of hereditary hemochromatosis
diagnosis
Due to the concealed condition of hemochromatosis, slow progress, and varying degrees of tissue involvement, the disease is often diagnosed at a later stage of the disease after significant tissue damage, and non-hereditary iron overload should be excluded, such as congenital hemolytic anemia (sickle cells). Anemia, thalassemia).
Hereditary hemochromatosis serum iron increased (>300mg / dl), serum transferrin saturation is a sensitive indicator of iron increase, when >50% has diagnostic value, serum ferritin increased, erythrocyte ferritin increased >200attograms / Red blood cells, using a chelating agent to remove iron sensitivity (500 ~ 1000mg intramuscular injection, according to the size of the patient to calculate the dose) can increase the output of urinary iron (> 2mg / 24h), in some cases, when the diagnosis is difficult, you can treat this As a diagnostic test, increased intrahepatic iron levels can be reflected by magnetic resonance imaging. Liver biopsy has been an important diagnostic measure. Currently, this test only provides a basis for diagnosing fibrosis (cirrhosis) when hepatic iron deposition and iron are detected. When the content is increased (average liver iron index > 2, mean liver iron concentration > 250 mol / gm), the diagnosis can be confirmed.
The use of the C282Y (most common mutation) and H63D (less common mutation) tests has simplified the genotypic clinical diagnosis and suitable screening methods for first-degree relatives, which account for more than 95% of patients with hemochromatosis.
Hemochromatosis must be differentiated from hemosiderosis, and hemosiderin or non-hemoglobin iron deposits too much in hemosiderosis tissue, but no fibrous tissue hyperplasia, does not cause tissue damage and organ function damage It can be divided into two categories: local and systemic. The latter is the overwhelming majority. The most representative of local hemosiderin is a disease with unknown etiology and systemic hemosiderin. Septicosis, caused by repeated blood transfusions due to the need of basic lesions, generally does not require treatment, and it can be identified by hepatic, pancreatic and cardiac function tests and liver puncture tests.
