Sickle cell disease is rare in northern Europe. Those affected suffer from anemia and circulatory disorders. The hereditary disease requires lifelong treatment.
Doctors refer to all diseases as sickle cell diseases in which a specific red blood pigment that deviates from the norm and is known as HbS occurs. The cause of these diseases is a change in the genetic make-up of those affected, which means that the red blood pigment – hemoglobin – tends to clump together.
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Forms, distribution and frequency of sickle cell anemia
Doctors distinguish different forms of sickle cell disease. The most severe form of the disease, formerly known as sickle cell anemia and now called sickle cell disease, occurs when an HbS trait has been inherited from both parents. Mixed forms with other haematopoietic disorders can also occur, including severe sickle cell beta-thalassemia, in which the HbS trait is inherited from one parent and the thalassemia trait is inherited from the other.
Sickle cell disease is very rare in Europe. According to estimates, the number of people affected in Germany is up to 1,000. The genetic makeup for sickle cell disease is more common in Africa, Latin America, Asia and the eastern Mediterranean. This distribution coincides with the distribution area of malaria or until the modern fight against the disease . Since people who have inherited the HbS trait from only one parent have a natural protection against malaria, the hereditary trait has proven to be a survival advantage in the distribution area of the tropical disease, although carriers of maternal and paternal HbS traits died early from sickle cell disease.
Typical symptoms of sickle cell disease
Due to the typical changes in the red blood pigment, the red blood cells ( erythrocytes ) are less easily deformed and, especially when the oxygen content in the blood is low, they change from the normal rounded indented shape to a sickle shape. Both the lower deformability and the sickle shape impede the sliding of the red blood cells in the blood vessels. If the blood cells get stuck in the narrow blood vessels, they impede the supply of oxygen and nutrients to the tissue. The result is circulatory disorders .
Crescent-shaped red blood cells also rupture easily and die prematurely. In addition, they are recognized as defective and held back by the spleen so that they are no longer available for oxygen transport.
Symptoms of sickle cell disease include:
- anemia
- Fever
- Repeated pain crises in the affected body regions (including often bone pain) as a result of circulatory disorders
- Jaundice due to the increased breakdown of red blood pigment
Serious complications include :
- “Splenic sequestration”: part or almost all of the red blood cells sink into the spleen within a few hours; the result is a state of shock
- “acute chest syndrome” (ATS): chest pain , cough , shortness of breath, and fever similar to pneumonia
- stroke
- “Priapism”: painful permanent erection, which can lead to damage to the cavernous bodies of the penis and infertility
- high blood pressure in the lungs
Age of onset: When do symptoms appear?
In the blood of small children, part of the red blood pigment has a different composition than later in life. This so-called fetal hemoglobin is not affected by the genetic change that leads to sickle cell disease. The first symptoms of the disease therefore only appear from the age of about six months, when the proportion of fetal hemoglobin has decreased significantly.
For this reason, sickle cell disease is usually diagnosed in childhood after the sixth month of life. In the case of less severe forms of the disease, symptoms and the final diagnosis can only occur in adulthood.
Diagnosis of sickle cell disease
The typical symptoms together with the mostly southern origin of those affected provide first indications of the presence of the disease. The exact diagnosis is made on the basis of blood tests and the analysis of the red blood pigment. In addition, the doctor examines the extent to which the disease has already caused damage to the skeletal system, especially the hip bones, and other organs such as the lungs, heart or eyes.
treatment options
The only therapy that can completely cure sickle cell disease is bone marrow or stem cell transplantation. Due to the risks associated with the treatment, which exist as a result of the preparation for transplantation, especially for adult patients and can range up to death, stem cell transplantation has so far only been carried out in a few, mostly very young patients worldwide.
Other treatments for sickle cell disease are aimed at relieving existing symptoms, preventing infection and preventing attacks of pain. A variety of measures and medications are used.
Blood transfusions are only carried out in exceptional cases, despite the often very low content of red blood pigment in the blood. Because the attempt to achieve “normal” blood values in those affected can lead to serious complications due to the poorer flow properties of the sickle cells.
Prognosis: Life expectancy in sickle cell anemia
In Europe and the US, about nine out of ten children with sickle cell disease survive to adulthood. However, the life expectancy of those affected is also shortened in industrialized countries. With optimal medical care, the average life expectancy is around 50 years. Apart from the limitations caused by an acute illness, the patients can lead a normal life.
A wish to have children can also be fulfilled. In order to rule out that sickle cell disease is transmitted to the child, there is the option of having a tissue sample taken from the placenta between the tenth and twelfth week of pregnancy and having it examined. If it turns out that the fetus is affected by the gene mutation, the pregnancy can be terminated at this point if the parents so wish. So-called pre-implantation diagnostics, which can be used to determine the genetic properties of an embryo created by artificial insemination before it is implanted in the womb, is prohibited in Germany.