SICKLE cell disease is a group of inherited blood disorders in which abnormal red blood cells lead to different medical problems, the most common of these is sickle cell anaemia.

Haemoglobin is a protein that is contained in red blood cells that allows them to carry oxygen from the lungs to the rest of the body. Most normal haemoglobin is referred to as Haemoglobin A, and is produced from genes that are inherited from each parent. In sickle cell anaemia, abnormal sickle haemoglobin, or Haemoglobin S, is inherited from each parent. This abnormal Haemoglobin S causes red blood cells to become rigid and deformed during times of stress. Under the microscope these deformed cells may take the shape of a sickle, which is a type of machete used to chop grass. These cells do not live as long as regular red blood cells and result in lower numbers of red blood cells, a condition known as anaemia.

These deformed red blood cells can block small blood vessels causing lack of oxygen or blood to certain areas. If one abnormal Haemoglobin S is inherited from only one parent, that person is said to have sickle cell trait.

About 10 per cent of all people in Jamaica have sickle cell trait, persons with the trait usually have none of the signs of sickle cell disease, but if two people with the sickle cell trait have a child, the child can have sickle cell disease. Also in Jamaica, sickle cell anaemia occurs one in every 300 births. Sickle cell anaemia occurs worldwide, but is more common in regions in which malaria is prevalent, such as Africa, Italy, Greece, Saudi Arabia, and India. It is thought that the trait confers better survival if malaria is contracted. Sickle cell disease is diagnosed by doing the sickle test and the type is confirmed by electrophoresis in the laboratory.

PROBLEMS EXPERIENCED WITH SICKLE CELL ANAEMIA

Patients with sickle cell anaemia may experience several problems. These include:

1. Dactylitis, also called hand-foot syndrome, is painful swelling of the toes and fingers and occurs at three to six months of age.

2. Acute chest syndrome, a potentially fatal complication presenting with fever, chest pain, cough, and lung changes on chest X-ray.

3. Persons with sickle cell disease are also prone to certain types of bacterial infection such as streptococcus pneumonia.

4. People with the disease are also at increased risk of stroke, especially in childhood.

5. An aplastic crisis occurs when the bone marrow stops working due to a viral infection and the haemoglobin levels fall rapidly.

6. Acute splenic sequestration where the spleen enlarges as the abnormal sickle red cells become trapped inside.

7. Painful crises are very common and occur when there is blockage of blood flow in the blood vessels all over the body. They can be triggered by dehydration, changes in temperature, infections, or fatigue.

8. Leg and foot ulcers due to the slow healing when there is injury or breakdown of skin.

9. Jaundice, due to the increased breakdown of red cells and the deposition of bilirubin pigment in the skin and mucous membranes (under the eyes).

These conditions may warrant a visit to an emergency department where they can be assessed and treated as several can become life-threatening.

TREATMENT

Treatment may involve pain management, hydration, antibiotics, warmth, and blood tests done to see if infection is present or transfusion is needed. Sickle cell anaemia cannot be cured but can usually be controlled. It can be prevented by genetic counselling and pre-pregnancy blood tests between partners to prevent persons with the trait from having children, which is a one in four chance per pregnancy.

Dr Romayne Edwards is a consultant emergency physician at the University Hospital of the West Indies and an associate lecturer at the University of the West Indies.