Sickle cell anemia is also known as sickle cell disease. This form of chronic and hereditary anemia is characterized by, among other things, very painful crises. Relatively widespread, it mainly affects people of black color: its prevalence is 0% to 40% in Africa and 10% among African Americans. Currently in the United States, 1 out of 500 African-American neonates have sickle cell anemia; the prevalence is 1 in 1,100 to 1,400 in the case of children of Hispanic origin. Residents of the West Indies and South America are also at high risk.
This disease is genetic: it is linked to the presence of abnormal hemoglobin genes that produce a non-functional hemoglobin protein called hemoglobin S. This deforms the red blood cells and gives them the shape of a crescent or ” a false (hence its falciform name), in addition to causing them to die prematurely. These deformed red blood cells are also known as sickle-cell anemia. This deformation makes the red blood cells fragile. These are destroyed quickly. In addition, their unusual shape makes their passage through the small blood vessels more difficult. Sometimes they block the blood supply of certain organs and cause circulatory accidents.
The accelerated destruction of red blood cells eventually progresses to haemolytic anemia – anemia caused by abnormally rapid destruction of red blood cells. Moreover, the abnormal shape of these can create obstructions in the capillaries and cause various problems related to poor blood circulation. Fortunately, sickle-cell anemia – people with this disease – can prevent complications and crises to some degree. They also live longer than before (Disease course).
Causes of Sickle Cell Anemia
The presence of hemoglobin S is explained by a genetic defect linked to the gene responsible for the production of hemoglobin. Several thousand years ago, at a time when malaria was very fatal, people with this genetic defect were more likely to survive because hemoglobin S prevents the malaria parasite from entering the red blood cells. Since this hereditary characteristic was an advantage for the survival of the species, it was maintained. Nowadays, it has become of course a handicap now that the malaria is well cured.
For a child to have sickle cell anemia, both parents must have passed on the hemoglobin S gene to him. If only one parent transmits the gene to him, the child will also carry the offending gene , but it will not suffer from this disease. On the other hand, it could transmit the gene in turn.
Course of the disease
The disease occurs around the age of six months and manifests itself differently from one patient to another. Some have only mild symptoms and undergo less of a crisis a year, during which the symptoms are exacerbated. In the past, it was often fatal in children under five. Although the death rate remains high in this age group, treatment now allows patients to live at least until adulthood.
They are many. Among the main ones are:
Vulnerability to infections. Bacterial infections are an important cause of complications in children with sickle cell anemia. This is why antibiotic therapies are often administered. Sickle-red cells damage the spleen, which plays an essential role in the control of infections. In particular, pneumococcal infections, which are very frequent and dangerous, must be feared. Adolescents and adults should also protect themselves from infections.
Growth and delayed puberty, frail constitution in adults. This phenomenon is caused by a lack of red blood cells.
Painful seizures. They usually manifest on the limbs, abdomen, back or chest, and sometimes on the bones. They are related to the fact that sickle-cell erythrocytes block blood flow in the capillaries. Depending on the case, they can last from a few hours to several weeks.
Visual impairment. When blood circulates poorly in the tiny vessels surrounding the eyes, it damages the retina and can lead to blindness.
Gallstones. The rapid destruction of sickle-cell erythrocytes releases a substance associated with jaundice, bilirubin. If the bilirubin level rises too much, gallstones can form. Moreover, jaundice is one of the symptoms associated with this form of anemia.
Hand and foot edema or hand-foot syndrome. Again, this is a consequence of the circulatory obstruction caused by abnormal red blood cells. This is often the first sign of illness in infants and in many cases is associated with fever and pain.
Ulcers of the legs. Since blood circulates poorly to the skin, it cannot receive the necessary nutrients. The cutaneous cells die consecutively and open wounds appear.
Priapism. These are painful and prolonged erections which can be explained by the fact that the blood accumulates in the penis without being able to return due to the sickle cell. These prolonged erections end up damaging the tissues of the penis and lead to impotence.
Acute chest syndrome ( acute chest syndrome ). Its manifestations are: fever, cough, sputum, pain in the chest, difficulty breathing (dyspnea), lack of oxygen (hypoxemia). This syndrome results from a pulmonary infection or sickle cell retained in the lungs. It seriously endangers the life of the patient and must be treated urgently.
Organic lesions. The chronic lack of oxygen damages the nerves as well as organs like the kidneys, liver or spleen. This type of problem sometimes causes death.
Stroke. By blocking cerebral circulation, sickle-cell erythrocytes can cause a stroke . About 10% of children with the disease were victims.