Sickle cell anemia (technically: drepanocytosis ) is an inherited disease of the red blood cells. A severe homozygous and a mild heterozygous form are distinguished. Since heterozygous sickle cell anemia confers a certain resistance to malaria, it is particularly widespread in areas at risk of malaria (Africa, Asia and the Mediterranean region).
What is sickle cell anemia?
Sickle cell anemia is one of the hemoglobinopathies (disorders of the red blood pigment hemoglobin). Hemoglobin is a complex protein made up of 4 subunits, which gives the red blood cells (erythrocytes) their color and binds oxygen for transport through the organism. For hepatic encephalopathy definitions, please visit definitionexplorer.com.
The altered hemoglobin (HbS) in sickle cell anemia tends to crystallize when there is a lack of oxygen. As a result, the erythrocytes deform into sickle cells and clog vessels, perish or are broken down prematurely. Sickle cell anemia is therefore characterized by hemolytic anemia and circulatory disorders.
Causes
Sickle cell anemia is caused by a genetic mutation that results in a single amino acid change in the amino acid sequence of hemoglobin β-subunits. The disease is inherited in an autosomal codominant manner.
Heterozygous patients have a healthy and a diseased allele; in them only about 1 percent of the hemoglobin is changed. Homozygous patients with two mutated alleles only have abnormal hemoglobin, which leads to a much more severe disease course. Even in a healthy organism, there is a physiological lack of oxygen in the small vessels, which causes the healthy hemoglobin to release its oxygen here.
In homozygous sickle cell anemia, this physiologically low oxygen partial pressure already leads to deformation of the erythrocytes. They clog the vessels and tend to dissolve. The hemoglobin released in the process binds nitrogen monoxide – an important vasodilator. The vessels are not only clogged, but also narrow. Due to the occlusion of many small end arteries, sickle cell anemia leads to circulatory disorders and damage to various organ systems.
Symptoms, Ailments & Signs
The symptoms of sickle cell anemia can vary in severity – depending on whether the person affected is a homozygous or heterozygous carrier of the responsible gene mutation.
Heterozygous carriers generally have no symptoms. Occasionally, however, hemolysis can occur. Many red blood cells are suddenly broken down, which can put a lot of strain on the kidneys in particular and lead to temporary oxygen deficiency. This form of hemolysis can be life-threatening. This is followed by such a disintegration of red blood cells in heterozygous genetic material carriers as a response to a lack of oxygen or certain medications.
Homozygous carriers, on the other hand, show the first symptoms just a few months after birth. Severe pain attacks can occur as a result of a lack of oxygen supply. Blood vessels are also blocked more frequently, which can lead to small and large heart attacks. Tissue death occasionally occurs in parts of the body that are not supplied with oxygen. Bone pain is very common.
People suffering from sickle cell anemia also have an increased susceptibility to infections and often complain of fever. The tendency to jaundice is greatly increased, which is due to the increased breakdown of destroyed erythrocytes. In addition, all the symptoms of anemia appear. This leads to paleness, pale mucous membranes, difficulty concentrating, a feeling of weakness and, in some cases, shortness of breath.
Diagnosis & History
In the first few months of life, every person produces a special fetal hemoglobin that is not affected by the genetic defect in sickle cell anemia. The disease therefore only becomes noticeable from the 6th month of life, when adult hemoglobin comes into play.
In childhood, it is mainly the homozygous patients who are conspicuous: they suffer from painful haemolytic crises at an early age. These include hemolytic anemia with pallor, jaundice, and weakness, as well as circulatory disorders and multiple small organ infarctions, typically in the brain and eye, spleen, lung, kidney, and heart, and in muscles and bones. Skeletal maturity is delayed. A typical symptom is also a painful permanent erection ( priapism ).
The diagnosis of sickle cell anemia is confirmed by laboratory tests, in particular by hemoglobin gel electrophoresis. A genetic test differentiates between homozygous and heterozygous diseases. Only half of those affected who are homozygous reach the age of 30. Because of the previously damaged lungs, lung infections are the most common cause of death.
In contrast to the severe form of the disease, heterozygous sickle cell anemia can remain inconspicuous for a long time. The first hemolytic crisis may only occur in the event of an unphysiological lack of oxygen, e.g. B. under extreme sporting stress or when staying at high altitude.
Complications
Sickle cell anemia can cause complications, some of which are severe. The effects are seen in a blockage of vessels in different parts of the body at the sickle cells. Doctors then speak of a sickle cell crisis.
If small vessels on the legs are blocked by sickle cell anemia, there is a risk of skin ulcers developing on the legs. Seizures are a neurological complication. In severe cases, cerebral hemorrhage or the patient can slip into a coma. The reason for this are blockages within the brain that require immediate therapy.
Another side effect of sickle cell anemia is the formation of gallstones. They are not the result of a vascular blockage, but are caused by the breakdown of red blood cells (erythrocytes). Bilirubin is one of the by-products of this breakdown. If the bilirubin level in the blood increases, the risk of gallstones, also known as pigment stones, increases.
Priapism is sometimes seen in males with sickle cell anemia. This is a painful and permanent erection. It is caused by the blockage of blood vessels within the penis. Without treatment, priapism can result in erectile dysfunction.
A feared complication of sickle cell anemia is blindness. It is caused by blockages in the vessels that supply the eyes. There is a risk of damage to the retina.
When should you go to the doctor?
Only medical treatment of this disease can prevent further complications and symptoms. Therefore, a doctor should be consulted at the first signs and symptoms of sickle cell anemia. A doctor should be consulted if the patient suffers from a permanent lack of oxygen. This often leads to severe tiredness or severe confusion, with those affected also being lethargic and no longer actively participating in everyday life. Furthermore, severe pain in the head or bones can indicate sickle cell anemia and must also be treated by a doctor.
The patients suffer from an increased susceptibility to infections and also from severe paleness or a high fever. If sickle cell anemia is not treated, the patient’s life expectancy is significantly reduced. Sickle cell anemia can be diagnosed and treated by a general practitioner. A visit to a specialist doctor may also be necessary for treatment. However, the further course of sickle cell anemia also depends heavily on the exact type of disease.
Treatment & Therapy
A causal therapy against sickle cell anemia does not (yet) exist. The only hope for a cure is bone marrow transplants – but these are only used in exceptional cases and are associated with relatively high mortality.
Routine treatment for sickle cell anemia focuses on delaying and relieving symptoms. In pain crises in particular, patients must be treated with analgesics. In the case of an acute drop in hemoglobin, partial blood exchange transfusions can be useful. Often in sickle cell anemia, the spleen has regressed and is not functioning properly; the patients then need careful vaccination protection, e.g. B. against pneumococci.
However, if the spleen does not regress, it can become pathologically enlarged (splenomegaly), making the anemia worse and requiring a splenectomy (removal of the spleen). In any case, patients with sickle cell anemia should also have regular outpatient routine examinations outside of crises.
Prevention
Since sickle cell anemia is a hereditary genetic defect, there is no prevention against the disease itself. However, heterozygous patients can contribute to a milder course by avoiding oxygen deficiency (e.g. due to high altitude or sporting activities), paying attention to careful vaccination protection and regularly get medical check-ups.
Aftercare
Sickle cell anemia is considered incurable. The focus of follow-up care for patients with sickle cell anemia is patient education, patient counseling (lifestyle), infection prophylaxis and vaccinations as well as routine diagnostics. The object of patient education is to inform the patient about the disease itself.
He must learn that sickle cell anemia can lead to life-threatening symptoms. The patient should be aware of the warning signs of acutely threatening complications (e.g. sepsis) and immediately lead to a presentation to a doctor. It is medically known that dehydration, hypothermia, hypoxia, acidosis and infections can trigger a flare in patients with sickle cell anemia.
Patient counseling therefore aims to sensitize the patient in his lifestyle so that he avoids these five factors as much as possible. The period between the attacks can be extended in this way. In addition to the general hygiene measures, the daily intake of penicillin is prescribed by a doctor as an infection prophylaxis for patients with sickle cell anemia.
In addition, to protect against infection, every patient with sickle cell anemia should receive at least one dose of 13-valent pneumococcal conjugate vaccine at follow-up. For routine diagnostics, it is recommended that patients with sickle cell anemia be presented to a specialized center at least once a year. There, the blood count, blood pressure, pulse rate, liver and kidney values, urine status and protein excretion must be examined clinically. An echocardiography should also be performed.
You can do that yourself
The disease is usually noticed within the first months or years of life. Naturally, at this age the patient cannot help himself sufficiently or improve his situation. The relatives and legal guardians are therefore responsible for providing adequate care for the offspring and working closely with the treating doctor.
Food intake should be optimized to support blood circulation. With certain foods, a targeted intake of nutrients can be achieved that stimulate blood formation. In addition, an oxygen-rich environment is particularly important for the infant. Rooms must be adequately ventilated and walks outdoors help to provide sufficient oxygen. Although these measures do not cure sickle cell anemia, they can positively support the child’s organism.
The child should not be in an environment where there is nicotine or other toxins in the air. Also avoid situations of overexertion and heavy stress. To protect against infection, care must be taken to ensure that contagion is reduced to a minimum. Leisure activities or sporting activities must also be tailored to the needs of the organism. Sufficient rest and rest are important in order not to unnecessarily strain the immune system.
