Sickle Cell Disease

Definition

Sickle cell disease (SCD) is a group of inherited health conditions that affect the red blood cells, causing them to develop abnormally into a crescent or "sickle" shape. These abnormally shaped cells can cause various complications due to their tendency to block blood vessels and their reduced lifespan.

Aetiology

Sickle cell disease is caused by a genetic mutation in the haemoglobin-Beta gene found on chromosome 11. For a child to be born with SCD, both parents must carry the sickle cell gene. There is a 25% chance with each pregnancy that the child will inherit SCD if both parents are carriers.

Pathophysiology

In SCD, the abnormal haemoglobin (HbS) causes red blood cells to become rigid and crescent-shaped. These sickle cells can obstruct capillaries and restrict blood flow to tissues and organs, leading to episodes of pain (sickle cell crises) and other complications. Additionally, the sickle cells have a shorter lifespan, leading to chronic haemolytic anaemia.

Risk Factors

Family history of sickle cell disease
African, Caribbean, Mediterranean, Middle Eastern, or Asian ancestry

Signs and Symptoms

Common signs and symptoms of sickle cell disease include:

Painful episodes (sickle cell crises)
Anaemia (causing fatigue, pallor, and shortness of breath)
Increased risk of infections
Delayed growth and puberty
Swelling in the hands and feet (dactylitis)
Jaundice (yellowing of the skin and eyes)

Investigations

Full blood count (FBC)
Haemoglobin electrophoresis to identify abnormal haemoglobin
Genetic testing to confirm the presence of the sickle cell gene
Newborn screening (heel prick test)

Management

Primary Care Management

Hydration and pain management: Encourage drinking plenty of fluids and use painkillers like paracetamol or ibuprofen for mild pain.
Infection prevention: Daily antibiotics (e.g., penicillin) and vaccinations (e.g., pneumococcal, meningococcal, and annual flu vaccines).
Folic acid supplements: To help with the production of red blood cells.

Specialist Management

Hydroxycarbamide (hydroxyurea): To reduce the frequency of sickle cell crises and the need for blood transfusions.
Blood transfusions: Regular transfusions may be needed for severe anaemia or to prevent stroke.
Stem cell or bone marrow transplant: The only potential cure for SCD but associated with significant risks.
Pain management: Stronger painkillers or hospitalisation for severe pain.

References

NHS. (2024). Sickle Cell Disease. Retrieved from NHS
Cancer Research UK. (2023). Sickle Cell Disease. Retrieved from Cancer Research UK
British Medical Journal (BMJ). (2022). Sickle Cell Disease: Diagnosis and Management. Retrieved from BMJ
American Society of Hematology (ASH). (2021). Clinical Practice Guidelines: Sickle Cell Disease. Retrieved from ASH