Sickle cell anaemia (SCA) is an autosomal genetic blood disorder with over-dominance by red blood cells that assume abnormal, rigid, sickle shape.
Normal haemoglobin is Hb A and abnormal haemoglobin is Hb S. There’s nothing to worry if you inherit an Hb A gene from both parents. However, if you inherit two Hb S genes, one from each parent, you have acquired sickle cell anaemia. If you inherit Hb A gene from one parent and Hb S gene from other, you are a carrier of sickle cell trait.
Haemoglobin, the substance inside red blood cells that carries oxygen around the body, comprises a haem unit within four globin chains (two alpha two beta). If the globin structure is abnormal, it can affect the oxygen-carrying capacity of the blood and cause a serious form of anaemia. Sickle cell anaemia is an inherited condition and may first appear very early in life. It is commonly found in populations in Africa, India, southern Europe and the Middle East. People who suffer from sickle cell anaemia are believed to go through ‘crisis’ at regular intervals whereby even a simple infection can bring on a life-threatening illness. Such episodes can last from a few hours to several days.
They can be caused by various reasons such as:
- Lack of oxygen at high altitudes
One advantage due to sickle cell condition is that it protects against the parasite which causes malaria. Thus, it means that it is more common in the place where malaria is endemic. In severe cases of sickle cell anaemia, studies have reported that an average life expectancy is 42 years in men and 48 years in women.
Signs & symptoms
When spleen destroys the abnormal red blood cells, it can lead to development of anaemia. This development can eventually cause fatigue, pale skin and shortness of breath. Sickle-shaped cells are inflexible and may block small blood vessels. It may show various symptoms like:
- Bone pain – which is the most common symptom
- Difficulty in breathing
- Priapism in men – a persistent, painful erection of the penis
- Abdominal pain, which is the result of spleen & liver damage
- Strokes & fits if the vessels in the brain are blocked
- Blood in urine due to damaged kidney
Threats from sickle cell anaemia
A prolonged suffering from sickle cell anaemia can cause:
- Recurrent infections
- Bone destruction – particularly that of the femur bone
- If the patient/ carrier is thinking of conceiving, she should first seek the guidance and advice of a doctor.
Diagnosis & treatment
For an accurate diagnosis of sickle cell anaemia, you may have to get blood tests done – a full body count, a blood smear analysis and haemoglobin electrophoresis. Regular blood transfusions are carried out to boost the levels of normal haemolglobin in the blood. Drugs to boost the levels of Hb F, another form of haemoglobin that resists sickling can be useful although these are not yet widely available. Also, a transplant of normal red blood cell-producing cells from the bone marrow of close relatives is another alternative. Gene therapy too may be possible to replace the abnormal haemoglobin gene.