Sickle cell anemia is one of the varieties of hemolytic blood diseases . 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 properly perform their function, anemic condition affects vital functions.
The appearance of red blood cells
The shape of a healthy person erythrocytes resembles two connected concave lenses, a disk with a thickened roller along the edge. They are easily bent, malleable and flexible, 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 sickle of a young moon, hence the name of the disease. But that is not the main problem.
Altered cells become rigid, poorly pass through a narrow capillary lumen. Blood stasis at the same time, hypoxia (oxygen starvation) of tissues is observed. The most affected cells are the brain, heart, kidneys, and retina.
Epidemiological characteristics of the disease
Inheritance of sickle cell anemia in humans is carried out on an autosomal recessive basis. That is, the affected genes are not on the sex chromosomes. For the full manifestation of the disease, the child must inherit recessive traits from both parents so that this allele is brought into a homozygous state.
Sickle cell anemia affects mainly 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 Middle East.
- The eastern and central regions of the African continent.
In other parts of Africa, the disease also occurs, but not continuously, but occurs sporadically.
Etiology of anemia
A hemoglobin molecule consists of a protein part - four globin subunits and a non-protein prosthetic group, represented by four divalent iron atoms (heme). Causes sickle cell anemia gene mutation. One that determines the sequence of amino acids in protein subunits.
The altered protein is part of hemoglobin, referred to as HbS (sickle cell hemoglobin anemia). It has several differences from normal HbA:
- decrease in mobility in an electric field, as well as solubility by 98%;
- provokes thickening of the blood;
- has a lower affinity for oxygen.
Signs of sickle cell anemia are acute when a decrease in the concentration of oxygen in the surrounding air, or rather, its partial pressure. Hemoglobin goes into a gel state, the structure of the contents 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 red blood cells provoke self-destruction of these cells. The body is not able to make up for their deficiency at the right speed.
Establishing diagnosis
Sickle cell disease is verified according to the general clinical picture and hematological analyzes.
The complex of symptoms characteristic of the disease:
- growth lag;
- enlarged spleen;
- pain from the musculoskeletal system;
- ulcers on the skin of the legs;
- respiratory tract infections;
- diseases of the cardiovascular system.
Under normal conditions, sickle-shaped red blood cells are not detected in a blood smear. To provoke their appearance, create local tissue hypoxia, bandaging the base of the finger for a while with a tourniquet.
If genotypically the disease is represented by a homozygous state, then blood changes occur quickly, not later than one hour. The heterozygous state of the genotype for this characteristic gives characteristic changes after one day.
In the photo: the appearance of sickle-shaped red blood cells in a blood smear.
Instead of testing for sickle cells, a clouding test is sometimes used. It is based on the poor solubility of hemoglobin S. A diagnosis can be confirmed after an electrophoretic study and the detection of pathological hemoglobin.
Features of the course of the disease in children
At an early age, hemolytic hereditary anemia is difficult. On average, the first anemic crises occur by the fifth month of life. Usually they are associated with some kind of infection.
The child has a fever, he is shivering. Tests reveal an insufficient hemoglobin content (anemia). Free hemoglobin appears in the urine, as well as its conversion products (bilirubin and others) in the urine, feces, 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 effect of sickle cell disease on physique
From the musculoskeletal system, the following changes are observed:
- curvature of the spine, excessive severity of its thoracic and lumbar bends;
- curvature of the extremities, muscle weakness, because of which the child refuses to walk;
- osteoporosis, brittle bones;
- growth of the cortical layer of bones;
- the shape of the skull, elongated in the parietal direction.
Patients are characterized by an asthenic type of constitution against the background of a general deficit in body weight. At the same time, the liver and spleen increase in volume, forming a convex stomach.
Consequences of thrombosis
Clogging of small vessels with red blood cells leads to swelling of the hands, feet, which causes severe pain. The consequences of anemic crisis are especially severe and painful for a small patient - necrotic changes in the hip and shoulder joints. They are accompanied by painful edema.
Due to thrombosis of the capillaries of the internal organs, hemorrhages in the tissues of the lungs, kidneys, liver, spleen, and retinal lesions are possible. Violation of the nutrition of tissues and skin integument leads to the appearance of trophic ulcers on the arms and legs, partial or complete loss of vision.
Manifestation of the disease in older patients
In adolescence, the disease can manifest itself weakly. Growth retardation is characteristic. Puberty is postponed for 2-3 years in comparison with healthy peers.
In women, due to sickle cell anemia, the onset of menstruation is later observed, pregnancy complications in the form of hypoxia, premature birth and spontaneous abortion.
In people of mature age suffering from this disease, characteristic morphological features are formed:
- rachiocampsis;
- small volume of the shoulder and pelvic girdles of limbs;
- disproportionately long arms and legs;
- deformed chest (in the form of a barrel);
- 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 pectoris and arrhythmia.
The disease can manifest itself in different ways. Some patients have severe and frequent pain attacks, while others have almost no symptoms, no pain. In between attacks of anemia, the patient leads a normal life.
Sickle Cell Anemia Treatment
Many symptoms and concomitant conditions for this disease determine several areas of therapy:
- Exposure to blood by intravenous infusion of saline to restore water balance in the body. Blood transfusion or the introduction of washed red blood cells, anticoagulants can restore impaired trophic tissue.
- 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 of infectious diseases resulting from low immunity. This is necessary to reduce the number of anemic attacks, to avoid sepsis.
- An oxygen mask to overcome the effects of hypoxia helps restore the partial pressure of oxygen to the required norm.
- The use of hydroxyurea (Hydrea), which can enhance the production of fetal hemoglobin in some patients. Such treatment reduces the frequency of necessary blood transfusions.
Surgical treatment of hereditary anemia involves 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, splenectomy - removal of the spleen may be required.
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:
- Flights over long distances and climbing mountains that lead to oxygen starvation.
- Exposure to low and high temperatures (bath, sauna, swimming in cold water).
- Any infections not even directly related to blood.
- Inadequate hydration. A person with sickle cell anemia should always have drinking water with him.
- Emotional and physical stress.
Help at home
Sickle cell anemia imposes restrictions on human life. To avoid exacerbations and alleviate the condition, you need to adhere to certain rules:
- Take dietary supplements with folic acid as prescribed by your doctor. As a rule, daily to stimulate the production of new red blood cells.
- Replenish the deficiency of folic acid by consuming a sufficient amount of whole grain cereals, fruits and herbs.
- Drink water regularly, avoiding thirst. This will maintain a low blood viscosity and avoid frequent recurrence of crises.
- To the extent possible, go in for sports or fitness with moderate exercise, master the skills of physical relaxation.
- Try to avoid emotional overload.
- Use a warming 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.
The prognosis of the disease may be different in different patients. Indeed, for some, frequent painful crises are the norm, while for others they happen very rarely.
Disease prevention measures do not exist, since the only way to acquire sickle cell anemia is through parental inheritance. Genetic counseling can provide answers about the carriage of the trait, the possible consequences and ways to overcome it.