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November 28, 2016 00:10

Iron overload diseases : causes, symptoms , diagnosis, treatment

When you receive iron (Fe) in quantities exceeding the needs of the body, it is deposited in the tissues as a hemosiderin.Deposition of iron resulting in damage to tissues (a total body iron content of & gt; 5 g) and called hemochromatosis.Local or generalized iron deposition without damaging the tissue is called hemosiderosis.Diseases of iron overload may be primary (genetically determined) in violation of iron metabolism, or secondary, caused by other diseases in which increased intake or release of iron.Iron can accumulate in almost all tissues, but the most common pathological changes develop when depositing iron in the liver, thyroid, pituitary, hypothalamus, heart, pancreas and joints.Liver damage leads to increased levels of aminotransferases (ALT and ACT), fibrosis and cirrhosis.

hemosiderosis

Local hemosiderosis may be due to recurrent bleeding in the body.Iron release from erythrocytes can lead to significant tissue Escrow hemosiderin.The most commonly affected organ is the lungs that is c

aused by recurrent pulmonary hemorrhage as idiopathic (eg, Goodpasture's syndrome) and pulmonary hypertension caused by chronic (eg, primary pulmonary hypertension, pulmonary fibrosis, severe mitral stenosis).Sometimes iron loss leads to the development of iron deficiency anemia as iron in the tissues can not be reutilizovano.

Renal hemosiderosis may be the result of intense intravascular hemolysis.Free hemoglobin is filtered in the glomerulus and iron is deposited in the kidney.Renal parenchyma is not damaged, but expressed gemosiderinuriya can lead to iron deficiency.

Ferroportinovaya disease

Ferroportinovaya disease occurs mainly among the residents of the south of Europe and is the result of an autosomal dominant gene mutation SLC 40 A1.The disease manifests itself in the first decade of life increased levels of serum ferritin with low or normal content of transferrin with a progressive increase in transferrin saturation in the 3rd and 4th decades of life.Clinical manifestations lighter than the disease Yar and include moderate liver disease and mild anemia.Large phlebotomy poorly tolerated, requires monitoring of levels of hemoglobin and transferrin saturation.

deficiency transferrin and ceruloplasmin

At deficiency of iron absorbed transferrin not bound to transferrin is included in the portal system and is deposited in the liver.The subsequent transfer of its place in the production of red blood cells is reduced due to the deficiency of transferrin.When there is a lack of ceruloplasmin deficiency ferroxidase, leading to a breach of the conversion of ferrous iron to ferric, which is necessary for communication with transferrin, which violates the iron transport from the intracellular pool of blood plasma, causing the accumulation of iron in tissues.

Violation of iron transport is suspected in patients with iron overload, which develops at an early age, or when detected signs of iron overload, but genetic studies show no abnormalities.Diagnosis is based on the determination of serum transferrin (or iron-binding capacity) and ceruloplasmin.experimental treatment.

Autosomal recessive form of hemochromatosis can be caused by a mutation transferrin receptor 2, a protein that controls the saturation of transferrin.Symptoms and signs are similar gemahromatozu HFE.

Secondary iron overload

Secondary iron overload can occur with thalassemia or sideroblastic anemia, which are diseases of erythropoiesis.Secondary acquired overload may occur after administration of exogenous iron in repeated massive blood transfusions and for the treatment of iron dextran.Each dose transfuziruemoy Blood ensures the supply of 250 mg of iron.Significant iron deposits are possible in the conduct of & gt;20g (m. E., About 80 units of blood).Iron overload may be due to abnormal erythropoiesis in thalassemia, sideroblastic anemia, hemoglobinopathies and erythrocyte enzyme abnormalities.In case of violation of erythropoiesis is an increase in iron absorption, possibly due pepsidinom.Violation of erythropoiesis can be found in the study of medical history of the patient.Iron overload is determined to increase the serum iron, transferrin saturation and serum ferritin.

phlebotomy may not always be shown, as these diseases are often accompanied by anemia, which limits the possibility exfusion enough blood.When there is used deferoxamine anemia [2.1 g daily for 8-24 hours in adults;20-40 mg / (kghden) for 8-24 hours in children] that should be administered as a slow intravenous infusion over night, 5-7 days a week, that effectively reduces the iron stores.When therapy with deferoxamine tachyphylaxis may occur therefore necessary to monitor the effectiveness of therapy (usually defining iron in the urine).Red color indicates urine output over 50 mg of iron per day.The goal of treatment and monitoring (with the level of serum iron and transferrin) are the same as for primary hemochromatosis.

Iron overload causes unclear

Parenchymal liver disease, alcoholic liver disease, nonalcoholic steatohepatitis and chronic hepatitis C may be associated with increased iron content in the body.disorders mechanism is unknown, although both may exist primary hemochromatosis, which should be avoided.If patients do not have primary hemochromatosis, iron reduction does not improve liver function.