Sickle Cell Disease - Kaylia McFarlane (2nd Year Doctor of Pharmacy Student)

Kaylia McFarlane

Sickle cell disease is a group of red blood cell disorders, that affects the protein haemoglobin (Centre for Disease Control and Prevention, 2020). Haemoglobin is a protein found in red blood cells, that is responsible for transporting oxygen around the body. Sickle cell disease results from a mutation in the gene that codes for the protein haemoglobin. As a result of this mutation in the haemoglobin gene,  the red blood cell becomes rigid and sticky, and its shape is distorted. Usually, red blood cells are shaped like a biconcave disk. However, in patients diagnosed with sickle cell disease, the red blood cells adopt a sickled, or crescent shape (National Heart, Blood and Lung Institute, 2020)

Sickle cell disease is a genetic blood cell disorder; therefore, it may only be inherited. An individual who only possesses one copy of the mutated haemoglobin gene, and a copy of the normal haemoglobin gene, is said to have the sickle cell trait. Individuals who have the sickle cell trait do not usually experience symptoms. However, in rare cases, some individuals with the sickle cell trait may experience symptoms such as an acute pain crisis. In cases where the body is subjected to extreme stress such as low oxygen levels, dehydration and high altitudes, the red blood cells of patients with the sickle cell trait may polymerize and become sickled, resulting in the individual becoming symptomatic (Center of Disease Control and Prevention, 2020). Additionally, persons with the sickle cell trait are still able to pass on a copy of the sickle cell gene to their children.

An individual may be born with sickle cell disease if they inherit a copy of the mutated haemoglobin gene from both parents. This may occur if both parents possess of the abnormal haemoglobin gene, that is, they possess the sickle cell trait or the disease; and both parents pass the gene to their children.  Regardless of the route, an individual is said to have the sickle cell disease once they possess two copies of the abnormal gene that codes for mutated haemoglobin (Center of  Disease Control and Prevention, 2020).

There are various types of sickle cell disease. These are Haemoglobin S β thalassemia, Haemoglobin SC, Haemoglobin SD, Haemoglobin SE and Haemoglobin SS. In all types of sickle cell disease, one of the two abnormal genes inherited by the individual codes for the protein, haemoglobin S.The most common types of sickle cell disease are Haemoglobin SS, Haemoglobin SC, and Haemoglobin S Beta Thalassemia.However, Haemoglobin SS is the most severe form of sickle cell disease and is commonly known as sickle cell anemia. Patients with sickle cell anemia possess both copies of the sickle gene that codes for the protein haemoglobin S (National Heart, Blood and Lung Institute, 2020).

 As previously mentioned, in patients diagnosed with sickle cell disease, the red blood cell adopts a sickled, or crescent shape. It is this abnormality which contributes greatly to the variety of complications that arise in sickle cell patients. These complications include joint problems, kidney problems, liver disorders, acute chest syndrome, and gallstones to name a few. A common complication of sickle cell disease is acute pain crisis, also known as vaso-occlusive crisis (Mayo Clinic, 2020).

Acute pain crisis occurs when the sickled blood cells obstruct blood flow. Consequently, patients will feel an intense stabbing or throbbing pain in any area of the body which may be quite severe and last up to a week.. Other complications associated with sickle cell disease include anemia, and an increased risk of infection (The National Health Service of the United Kingdom, 2019)

Sickle cell disease is common amongst individuals of African, Middle Eastern, Indian, Asian and Mediterranean descent. It is estimated that 10% of the Jamaican population carries the sickle cell trait, and that 1.8 in every 1000 individuals in Jamaica has the sickle cell disease.

 Due to the nature of the condition, treatment of sickle cell disease is mainly focused on alleviating pain and preventing the development of further complications. Broad spectrum antibiotics are administered to treat acute chest syndrome; a symptom of sickle cell disease (children’s hospital.org, n.d)

Hydroxyurea is a popular medication which was approved by the Food and Drug Administration for the treatment of sickle cell disease in both adults and children. Hydroxyurea helps to reduce the complications associated with sickle cell disease, by increasing the amount of haemoglobin F (also known as fetal haemoglobin) in the body. (American Society of Hematology, n.d.) . The increase in haemoglobin F delays the sickling of the red blood cells, and thus reduces the occurrence of some associated complications, such as acute pain crisis. L glutamine oral powder is another medication that is administered to sickle cell patients to decrease the incidence of acute pain crises (Mayo Clinic, 2020). 

  Folic Acid supplements are also recommended for use in  sickle cell patients, as folic acid  facilitates the production of new blood cells (medlineplus.gov, 2020). A stem cell transplant is sometimes performed, and it involves the replacement of bone marrow affected by sickle cell with bone marrow from a healthy donor. However, because of the risk associated with this procedure, it is not performed often and is usually reserved for children with the condition, as well as patients who have significant complications associated with the condition. 

REFERENCES

• https://www.mayoclinic.org/diseases-conditions/sickle-cell-anemia/symptoms-causes/syc-20355876#:~:text=Sickle%20cell%20anemia%20is%20an,like%20sickles%20or%20crescent%20moons. Retrieved June 7,2021
• https://www.nhlbi.nih.gov/health-topics/sickle-cell-disease Retrieved June 7,2021
• https://www.nhs.uk/conditions/sickle-cell-disease/ Retrieved June 7,2021
• https://www.cdc.gov/ncbddd/sicklecell/facts.html Retrieved June 7, 2021
• https://www.hematology.org/-/media/Hematology/Files/Education/Hydroxyurea-Booklet.pdf  Retrieved June 7,2021
• https://www.cdc.gov/ncbddd/sicklecell/documents/scd%20factsheet_sickle%20cell%20trait.pdf Retrieved June 7,2021
• https://www.childrenshospital.org/conditions-and-treatments/conditions/s/sickle-cell-disease/diagnosis-and-treatment , Retrieved June 7, 2021
• https://medlineplus.gov/ency/article/000527.htm , Retrieved June 7, 2021