sickle cell anemia

Sickle cell anemia

Sickle cell anemia is a genetic disorder, in which there is mutation of the Hemoglobin “s” gene causing abnormal Red Blood Cells. These cells are not flexible and hence cause complications. However a few have both the HBS genes mutated and suffer from the disease whereas a majority only have sickle cell trait and these are carriers

People living in the tropical and sub-tropical countries like India, African continent are mostly affected.

Those having sickle cell trait are resistant to malarial infection but those having the disease are vulnerable.

Let us see how sickle cell anemia can lead to various complications; emergencies in sickle cell anemia

Firstly is the vaso-oclusive crisis. The abnormality in the sickled RBC’s cause sticking of these cells to each other causing rouleaux formation which obstruct the blood vessels, ceasing the nutrient and oxygen supply to the affected organ. Stroke in children occurs because of this pathology. “Silent stroke” is more fatal because it is 5 times more common and patients don’t have symptoms and thus these cases are unreported. The affected organ is damaged and there is pain. It finally loses its functions and dies off. When blood flow to the penis or the lungs is obstructed, it is an emergency. Priapism or painful erected penis occurs when penis is infarcted.

What happens in the lungs?

When the blood supply is compromised, parts of the lungs get infracted and die(necroses) . Also lungs get infected with atypical bacteria and pneumonia occurs. This is called acute chest crisis because chest pain also occurs and it needs to be treated promptly with antibiotics.

Why auto-splenectomy does occur in SCA? What is splenic sequestration crisis?

Spleen undergoes multiple infarcts since childhood. Parts of spleen get necrosed and finally by the age of 8 spleen are completely destroyed. OPSI or overwhelming post splenectomy infections occur due to this. Also in the abnormal spleen, pooling of blood occurs into the spleen, which reduces the volume of the circulatory blood causing hypovolaemia which causes shock. If these patients are not treated with Blood Transfusion then they might die in 3-4 hours.

Why is anemia there?

Due to fragility of the blood cells, there is increased destruction reducing the number of these cells. Also an infection like parvovirus b19 can precipitate anemia by affecting the formation of these blood cells. When levels drop very low it is a life threatening situation of these patients.

Which are the organs affected in SCA?

Apart from the organs described above, Gall bladder, bones, kidneys and the heart too are affected. Gall stones occur. Leg ulcers are common. Even the eyes are affected; the retina gets detached causing blindness. There is renal failure with loss of proteins and blood in urine worsening the anemia as well as causing hypertension

Bones?

Yes, there is infection of bones called osteomyelitis. The bacteria Salmonella is the main culprit. Joints like hip are affected in which the head of femur undergoes avascular necrosis.

Heart Failure? How does it manifest?

The pressure of blood vessels in the lungs is constantly raised which puts a tremendous strain on the heart eventually leading to heart failure. Breathlessness, unable to exercise and fainting episodes denote heart failure.

Living with Sickle cell anemia

Life expectancy of patients with SCA has increased due to advancement in medicine. But such a child has to be on observation throughout his life, which further puts financial burden on the family. A daily dose of 1 mg of folic acid is highly recommended. Also those living in malaria endemic countries have to take anti-malarial drugs lifelong. Blood Transfusion might be need more frequently in such patients. However, the disease in incurable and prevention is the alternative.

Prevention

Genetic Counseling of both parents is must. In India, consanguineous marriages are common increasing the incidence of this disease. If a child is affected with SCA, all relatives should undergo blood testing to evaluate the incidence of this disease in the family. Familial Support