Sickle cell anemia is a type of hemolytic blood disease. The nature of the disease is genetic, associated with a violation of the structure of genes encoding erythrocyte globins, due to which their shape changes. Defective blood cells cannot perform their function properly, the anemic condition affects vital functions.
Appearance of red blood cells
The shape of a he althy person's erythrocytes resembles two connected concave lenses, a disc with a thickened ridge along the edge. They are easily bent, pliable and elastic, which allows them to pass through the smallest capillaries. Thanks to hemoglobin, which fills red blood cells, an effective exchange of gases is carried out in all tissues.
The presence of sickle cell anemia in humans leads to a change in the shape of red blood cells. Red blood cells resemble the crescent of a young moon, hence the name of the disease. But the mainthat's not the problem.
Changed cells become rigid, poorly pass through a narrow capillary lumen. At the same time, the blood stasizes, hypoxia (oxygen starvation) of the tissues is observed. The cells of the brain, heart, kidneys, and retina suffer the most.
Epidemiological characteristics of the disease
Inheritance of sickle cell anemia in humans is carried out according to an autosomal recessive trait. That is, the affected genes are not on the sex chromosomes. For full manifestation of the disease, the child must inherit recessive traits from both parents in order for this allele to be homozygous.
Sickle cell anemia mostly affects children. Since adolescence, it is less common.
The disease is mainly confined to certain geographical areas:
- Apennine and Balkan Peninsulas.
- Eastern Mediterranean (Turkey), Cyprus.
- India.
- Countries of the Middle and Near East.
- Eastern and central regions of the African continent.
In other parts of Africa, the disease also occurs, but not constantly, but occurs sporadically.
Etiology of anemia
The hemoglobin molecule consists of a protein part - four globin subunits and a non-protein prosthetic group, represented by four ferrous iron atoms (heme). A gene mutation causes sickle cell anemia. The one that determines the sequence of amino acids in proteinssubunits.
The altered protein is part of hemoglobin, referred to as HbS (sickle cell hemoglobin). It has a number of differences from normal HbA:
- decrease in mobility in an electric field, as well as solubility by 98%;
- causes blood to thicken;
- has a lower affinity for oxygen.
Signs of sickle cell anemia are acutely manifested by a decrease in the concentration of oxygen in the surrounding air, or rather, its partial pressure. Hemoglobin goes into a gel-like state, the structure of the content of blood cells and their shape changes.
Sickle cells provoke hypoxia in the tissues, which means that the partial pressure of oxygen decreases even more, and the symptoms of sickle cell anemia are more pronounced.
Pathological changes in metabolic processes in erythrocytes provoke self-destruction of these cells. The body is not able to make up for their lack at the right speed.
Diagnosis
Verify sickle cell disease by clinical picture and haematological tests.
Complex of symptoms characteristic of the disease:
- stunting;
- enlarged spleen;
- pain in the musculoskeletal system;
- leg ulcers;
- respiratory infections;
- diseases of the cardiovascular system.
Under normal conditions, sickle-shaped erythrocytes are not detected in a blood smear. To provoke their appearance, local tissue hypoxia is created by temporarily bandaging the base of the finger with a tourniquet.
If the disease is genotypically represented by a homozygous state, then blood changes occur quickly, no later than one hour. The heterozygous state of the genotype for this trait gives characteristic changes in one day.
In the photo: the appearance of sickle-shaped red blood cells in a blood smear.
Instead of the sickle cell test, the haze test is sometimes used. It is based on the weak solubility of hemoglobin S. Confirmation of the diagnosis can be obtained after an electrophoretic study and the detection of pathological hemoglobin.
Features of the course of the disease in children
Hemolytic hereditary anemia is severe at an early age. On average, the first anemic crises appear by the fifth month of life. Usually they are associated with some kind of infection.
The child has a fever, he is shivering. Analyzes reveal insufficient hemoglobin content (anemia). Free hemoglobin appears in the urine, as well as its conversion products (bilirubin and others) in the urine, feces, and blood serum.
A large amount of bilirubin in plasma leads to staining of the mucous membranes and skin. They become yellowish. Pigmented gallstones may form.
The impact of sickle cell disease on the physique
The following changes are observed on the part of the musculoskeletal system:
- curvature of the spine, excessive expression of its thoracic and lumbar curves;
- curvature of the limbs, weakness of the muscles, because of which the child refuses to walk;
- osteoporosis, brittle bones;
- growth of the cortical layer of bones;
- shape of the skull, elongated in the parietal direction.
For patients, an asthenic type of constitution is characteristic against the background of a general lack of body weight. At the same time, the liver and spleen increase in volume, forming a bulging belly.
Consequences of thrombosis
Clogging of small vessels with erythrocyte mass leads to swelling of the hands and feet, which causes severe pain. The consequences of an anemic crisis are especially severe and painful for a small patient - necrotic changes in the hip and shoulder joints. They are accompanied by painful swelling.
Due to thrombosis of the capillaries of the internal organs, hemorrhages in the tissues of the lungs, kidneys, liver, spleen, retinal lesions are possible. Malnutrition of tissues and skin leads to the appearance of trophic ulcers on the arms and legs, partial or complete loss of vision.
Disease manifestation in older patients
In adolescence, the disease may be mild. Growth retardation is characteristic. Puberty is delayed by 2-3 years compared to he althy peers.
Women due to sickle cell anemia have a late onset of menstruation, complications of pregnancy in the form of hypoxia,premature birth and spontaneous abortion.
In people of mature age suffering from this disease, characteristic morphological features are formed:
- curvature of the spine;
- small volume of the shoulder and pelvic girdle of limbs;
- disproportionately long arms and legs;
- deformed chest (barrel-shaped);
- elongated skull shape.
Over time, the disease is complicated by impaired lung function due to fibrous replacement of tissues damaged by heart attacks, priapism (painful erection leading to impotence), angina and arrhythmia.
The disease can manifest itself in different ways. Some patients have severe and frequent pain attacks, while others have practically no symptoms, no pain. Between bouts of anemia, the patient leads a normal life.
Treating sickle cell anemia
Many symptoms and concomitant conditions in this disease determine several directions of therapy:
- Influence on the blood by intravenous infusion of saline to restore the water balance in the body. Blood transfusion or the introduction of washed red blood cells, anticoagulants allow you to restore disturbed tissue trophism.
- Relief of pain attacks during exacerbations. In this case, both conventional analgesics and narcotic drugs are used, depending on the severity of the pain syndrome.
- Immunization and treatment arising from low immunityinfectious diseases. This is necessary to reduce the number of anemic attacks, to avoid sepsis.
- An oxygen mask to overcome the effects of hypoxia helps to restore the partial pressure of oxygen to the required norm.
- The use of hydroxyurea (Hydrea), which can increase the production of fetal hemoglobin in some patients. This treatment reduces the frequency of needed blood transfusions.
Surgical treatment of hereditary anemia is the transplantation of hematopoietic tissue - red bone marrow. Best results are achieved in patients under the age of sixteen with a suitable tissue donor.
According to indications, a splenectomy may be required - removal of the spleen.
Factors provoking anemic crisis
Under certain conditions, an exacerbation of the disease is more likely. To avoid a crisis, you need to pay attention to risk factors:
- Flying long distances and climbing mountains that lead to oxygen starvation.
- Exposure to low and high temperatures (bath, sauna, bathing in cold water).
- Any infections, even those not directly related to the blood.
- Inadequate hydration. A person with sickle cell disease should always have drinking water with them.
- Emotional and physical stress.
Help at home
Sickle cellanemia imposes restrictions on human life. To avoid exacerbations and alleviate the condition, you need to follow certain rules:
- Take folic acid dietary supplements as directed by your he althcare professional. Generally daily to stimulate the production of new red blood cells.
- Make up for folic acid deficiency by eating enough whole grains, fruits and greens.
- Drink water regularly without feeling thirsty. This will help maintain low blood viscosity and avoid frequent recurrence of crises.
- As far as possible, engage in sports or fitness with a moderate load, learn physical relaxation skills.
- Try to avoid emotional overload.
- Use a warm compress or heating pad to reduce pain.
- At the first suspicion of an infection, consult your doctor. Timely treatment will reduce the likelihood of a "full-sized" attack of anemia.
Prognosis may vary from patient to patient. Indeed, for some, frequent painful crises are the norm, while for others they happen very rarely.
There are no measures to prevent the disease, since the only way to acquire sickle cell anemia is through inheritance from parents. Genetic counseling can provide answers about carrying the trait, possible consequences and ways to overcome it.
