Sickle cell anemia is also called sickle cell anemia, sickle cell anemia, sickle cell anemia, hemoglobin S or, in English, sickle cell disease. This form of chronic and hereditary anemia is characterized, among other things, by very painful attacks. Relatively widespread, it mainly strikes people of black color: its prevalence is 0% to 40% in Africa and 10% among African Americans. Currently in the United States, 1 in 500 African American newborns have sickle cell disease; the prevalence is 1 in 1 to 100 for Hispanic children. People in 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 distorts red blood cells and makes them look like a crescent or a crescent. a scythe (hence its sickle-shaped name), in addition to causing them to die prematurely. These deformed red blood cells are also called sickle cells. This deformation makes the red blood cells fragile. These destroy themselves quickly. In addition, their unusual shape makes their passage through small blood vessels more difficult. They sometimes block the blood supply to certain organs and cause circulatory accidents.

The accelerated destruction of red blood cells eventually progresses to hemolytic anemia – that is, anemia caused by abnormally rapid destruction of red blood cells. In addition, the abnormal shape of these can create obstructions in the capillaries and cause various problems related to poor circulation of the blood. Fortunately, sickle cell patients – people with this disease – can prevent complications and seizures to some extent. They also live longer than before (Course of the disease).

Causes

The presence of hemoglobin S is explained by a genetic defect linked to the gene responsible for the manufacture of hemoglobin. Several thousand years ago, at a time when malaria killed many people, people with this genetic defect had a better chance of survival because hemoglobin S prevents the malaria parasite from entering red blood cells. As this hereditary characteristic was an advantage for the survival of the species, it was therefore maintained. Nowadays, it has of course become a handicap now that malaria is well treated.

In order for a child to have sickle cell anemia, both parents must have passed on the hemoglobin S gene to them. If only one parent passes the gene to them, the child will also carry the faulty gene. , but he will not suffer from this disease. On the other hand, he could transmit the gene in turn.

Course of the disease

The disease appears around the age of six months and manifests itself differently from one patient to another. Some have only mild symptoms and have less than one attack per year, during which the symptoms are exacerbated. In the past, this disease was often fatal in children under the age of five. Although the death rate remains high in this age group, treatments now allow patients to live at least to adulthood.

Complications

They are many. Among the main ones, we find these:

• Vulnerability to infections. Bacterial infections are a major cause of complications in children with sickle cell anemia. This is why antibiotic therapy is often given to them. Sickle cells damage the spleen, which plays a vital role in infection control. In particular, pneumococcal infections, which are very frequent and dangerous, are to be feared. Adolescents and adults should also protect themselves against infections.
• Growth and puberty delayed, constitution frail in adults. This phenomenon is caused by a lack of red blood cells.
• Painful crises. They usually appear on the limbs, abdomen, back or chest, and sometimes on the bones. They are linked to the fact that sickle cells block blood flow in the capillaries. Depending on the case, they can last from a few hours to several weeks.
• Visual disturbances. When blood circulates poorly in the tiny vessels that surround the eyes, it damages the retina and can therefore lead to blindness.
• Gallstones. The rapid destruction of sickle cells releases a substance associated with jaundice, bilirubin. However, if the bilirubin level rises too much, gallstones can form. Moreover, jaundice is one of the symptoms associated with this form of anemia.
• Edema of the hands and feet or hand-foot syndrome. Again, this is a consequence of circulatory obstruction caused by abnormal red blood cells. It is often the first sign of illness in infants and in many cases is associated with fever attacks and pain.
• Leg ulcers. Since the blood circulates poorly to the skin, the skin cannot receive the necessary nutrients. One after the other, skin cells die and open wounds appear.
• Priapisme. These are painful and prolonged erections which are explained by the fact that blood accumulates in the penis without being able to flow back because of the sickle cells. These prolonged erections end up damaging the tissues of the penis and lead to impotence.
• Acute chest syndrome (acute chest syndrome). Its manifestations are as follows: fever, cough, expectoration, pain in the chest, difficulty in breathing (dyspnea), lack of oxygen (hypoxemia). This syndrome results from a lung infection or sickle cell cells trapped in the lungs. It seriously endangers the life of the patient and must be treated urgently.
• Organic lesions. Chronic lack of oxygen damages nerves as well as organs such as the kidneys, liver or spleen. This type of problem sometimes causes death.
• Stroke. By blocking circulation to the brain, sickle cells can cause a stroke. About 10% of children with the disease have suffered from it.