What is Sickle Cell Anemia?
The most common anomaly in hemoglobin structure is hemoglobinopathy. In this case, in the case of homozygous carriage, we have in mind sickle cell anemia, and in case of heterozygous carriage, sickle cell anomaly.
The disease was first described in 1910. Herrick from a black American student from the West Indies. Subsequently, sickle cell anemia was described by other scientists: Washburn (1911), as well as Cook, Meyer (1915).
Sickle cell anemia is the most common in Central Africa. It is often found among some peoples of India, on the island of Ceylon, in Turkey, Iran, Iraq, Algeria, Tunisia, Kuwait, on the island of Cuba. In our country, hemoglobinopathy S was described by L. T. Dzhafarova, V. Yu. Dikova in 1962. The disease is most common in Azerbaijan and Georgia.
The sickle phenomenon is a consequence of the decreased solubility of hemoglobin, which gave oxygen. Hemoglobin A, devoid of oxygen, is soluble in half as much as hemoglobin A, saturated with oxygen. The solubility of hemoglobin S with oxygen release decreases 100 times. This leads to gel formation. Microscopy reveals crystals with a size of 1.5 microns, resembling sickle-shaped red blood cells in shape, disappearing after the addition of oxygen.
Symptoms of Sickle Cell Anemia
Homozygous form of hemoglobinopathy S
The clinical picture of the homozygous form of hemoglobinopathy S is composed of moderate normochromic anemia and thrombotic complications. The disease begins to manifest only a few months after birth, since fetal hemoglobin does not contain a pathological P-chain. In addition, a high level of fetal hemoglobin in young children after the appearance of the pathological chain reduces sickle due to increased affinity for oxygen.
The most characteristic symptoms of sickle cell anemia in young children are damage to the osteoarticular system: sharp pain in the joints, swelling of the feet, hands, legs. These changes are associated with thrombosis of the vessels that feed the bones. Aseptic necrosis of the femoral and humerus heads is often observed. Thrombosis often causes pulmonary infarction.
Patients are often tall, thin, with a curved spine; they often have a high tower skull, altered teeth, infantilism, and sometimes signs of eunuchoidism. Abdominal pain can mimic various diseases of the abdominal cavity. A frequent complication of sickle cell anemia is visual impairment associated with a change in the vessels of the retina. Vascular thrombosis leads to the development of arteriovenous anastomoses; on the retina there may be peripheral vascular and fibrous proliferates with areas of black pigmentation. Vitreous hemorrhages and retinal detachment often lead to blindness.
Ulcers are found on the lower legs, especially in sickle cell anemia patients in Jamaica.
Thrombosis of large vessels lead to heart attacks in the kidneys and lungs; thrombosis of cerebral vessels is not uncommon.
The spleen in young children is large, but in the future it decreases, and after 5 years the enlargement of the spleen is rare. This is due to “autosplenectomy” as a result of spleen fibrosis, often affected by heart attacks. Liver with sickle cell anemia is also enlarged.
Heterozygous form of hemoglobinopathy S (sickle cell anemia)
Patients never know about their illness; their hemoglobin content and well-being are normal. The only symptom in some patients is hematuria associated with minor renal vascular infarction. The content of pathological hemoglobin in the red blood cells of patients with a heterozygous form of hemoglobinopathy is small, and the clinical manifestations of the disease are observed only during hypoxia: in case of severe pneumonia, during anesthesia. Thrombosis at high loads in the mountains, thrombotic complications during scuba diving are described.
It should be noted that thrombosis affects any organs suffering from sickle cell anemia. The sickle shape of red blood cells is detected using a metabisulfite test. With hemoglobin electrophoresis, 2 large fractions are determined – hemoglobin A and hemoglobin S.
The combination of the heterozygous form of sickle cell anemia with beta-thalassemia is common. The disease is much milder than homozygous P-thalassemia and the homozygous form of sickle cell anemia. A combination of P-thalassemia with hemoglobinopathy S is characterized by a significant increase in the spleen, pronounced hypochromia and erythrocyte targeting. Thrombotic complications occur, but much less frequently than with sickle cell anemia. With this form of the disease, joint pains and severe bouts of abdominal pain are noted.
Children suffering from the disease lag behind their peers in physical development. In red blood cells, a significant increase in the level of fetal hemoglobin is detected. In beta-thalassemia, in addition to HbS, A2 and fetal hemoglobin, hemoglobin A is detected.