Sickle cell anemia: what is it?
System pathology of the blood, which affects the structure of hemoglobin, leading to changes in shape of red blood cells and reduce their number, called «sickle cell anemia». This pathology has a genetic hereditary. It is much more common in populations with a tropical climate.
The mechanism of disease development
Erythrocytes have a biconcave disk shape and a size of about 7 – 8 µm in diameter. These characteristics allow them to pass freely through the smallest vessels (capillaries) and to perform the basic biological function – transport oxygen to tissues and return carbon dioxide transfer in the lungs. Inside the red blood cells contain the protein hemoglobin. It consists of 4 protein subunits and one pigment heme group containing iron ions. Such a structure allows 1 molecule of hemoglobin can bind up to 4 molecules of oxygen during the passage of erythrocytes through the lungs. In tissues where partial pressure of oxygen is low, it is liberated and carbon dioxide sequestration.
There are several types of hemoglobin. In adults, almost all red blood cells contain hemoglobin A. In sickle cell anemia the hemoglobin is broken amino acid composition (hemoglobin S). This leads to the fact that when binding the carbon dioxide changes its tertiary structure, while red blood cells become sickle shape and lose their elasticity. During the passage of the modified red blood cells through capillaries, they are destroyed, which leads to the development of anemia (reduction in the number of erythrocytes and hemoglobin per unit volume of blood).
Sickle cell anemia is a hereditary disease. Cause changes in the structure of hemoglobin is a defect (mutation) of the gene RGR. Transmission of the defective gene is on an autosomal-recessive pattern, the disease develops from early childhood. For sickle cell anemia have a higher incidence in countries with a hot climate. It is believed that it is a protective evolutionary mechanism, since people with this disorder are immune to malaria, which is very common in countries with hot and humid climate.
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The main manifestation of sickle-cell anaemia is the development of symptoms reduced level of hemoglobin and number of erythrocytes in the blood. It includes General weakness, paleness of skin and visible mucous membranes, reduced capacity to work. Sometimes during high-intensity destruction of red blood cells may develop hemolytic jaundice (increase of bilirubin level associated with its increased formation of hemoglobin of the destroyed red blood cells), in which the skin and the sclera of the eyes become jaundiced coloration.
Together with clinical manifestations of anemia can occur swelling of the hands and feet, pain at the top of the stomach to the left (as a result of a reactive increase of the spleen, which is a «cemetery» of erythrocytes). Due to clogging of the small capillaries of the tissues destroyed mutated erythrocytes in sickle cell anemia frequently develop with ulcerative defects of the skin, aseptic necrosis (death) of the tissues of various localization, as well as damage to the eyes, heart and lungs. With necrotic changes in the tissues can join a secondary bacterial infection. When this pathological process is purulent, there are signs of General intoxication (severe weakness, high fever, chills and body aches).
Symptoms of sickle cell anemia has similarities with the manifestations of other diseases of the blood system and bone marrow, so the confirmation of the diagnosis requires laboratory investigations. It includes microscopic examination of stained smears of blood, which reveal a characteristic sickle shape of red blood cells.
Also necessarily performed General clinical blood analysis with determination of the hemoglobin level that provides an opportunity to assess the severity of anemia. Conduct biochemical analysis of blood to determine the level of total, direct and indirect bilirubin. According to the degree of increase in the concentration of these compounds provides a conclusion about the intensity of process of destruction of red blood cells.
Since the disease is genetic, inborn, radical methods of treatment no. Therapeutic interventions aimed at restoring red blood cell count and hemoglobin levels with iron supplements and folic acid, a symptomatic reduction in pain levels (using anti-inflammatory drugs), and prevention of secondary bacterial infection of ulcers of the skin or soft tissues of various localization.
During the process of increased destruction of red blood cells and increase the level of bilirubin in the blood is necessarily performed detoxication therapy in a health facility, which involves injecting a significant amount of salt solutions and glucose on the background of the use of vitamins and diuretics. Today to cure sickle-cell anemia is impossible, it is therefore important to prevent its development, which is the genetic survey of parents at the planning stage of pregnancy.