Sickle Cell Anemia (Sickle Cell Disease)

Sickle cell anemia or sickle cell disease (SCD) is a disorder of the red blood cell. People with this disorder have a problem with their hemoglobin, which is a protein in the red blood cell whose function is to carry oxygen. A normal red blood cell is disc-shaped, but for people with sickle cell anemia, it is sickle-shaped, hence the name (Costa & Conran, 2016). This abnormal shape is brought about by the defective hemoglobin which forms into stiff rods. As such, the sickle-shaped cells are not flexible enough to change shape as they move along the blood vessel to carry oxygen and they end up bursting apart. A normal cell has a lifespan of 90 to 120 days, but the sickle cells usually last for 10-20 days. The body needs to regenerate more cells to replace the dead ones. Due to the high rate of destruction of the red blood cells for people with SCD, their body cannot make enough replacements, leading to a situation where the red blood cells are not enough, resulting to anemia (Costa & Conran, 2016). The inflexibility of the red blood cells can make them stick to vessel walls, blocking or stopping the blood flow altogether. As a result, oxygen cannot reach the affected tissues causing sudden severe pain. 

Historical Overview 

According to Wailoo (2017), SCD was first documented in 1910 though there were earlier reports in the late 19 th century. On 15th November of this year Dr. James Herrick, a cardiologist published the first official literature on the disorder when his patient, Walter Clement Noel displayed the unique characteristic crescent shape of hemoglobin, typical of homozygous sickle cell disease. In 1911, the second publication of the disease was released on a female patient who demonstrated sickle cell disease symptoms whose blood film showed the sickle hemoglobin; same as the first case. 

In 1915, the third case was published, and this time around, a genetic link was made. The patient was a 21-year old female with the symptoms of SCD. Her father's blood was also sampled and at the time of examination, the red blood cells were the normal disc-shaped. After a few days, however, some abnormal cells were evident, suggesting that the disorder was inherited. In 1922, the fourth case was published by Verna Mason of a 21-year old male. The researcher linked these first four cases, as all the patients originated from Africa. This was the first time the term SCD was used. At around this time, more cases were reported which strengthen the medical knowledge. In 1949, hemoglobin electrophoresis was first used to detect the disease. Throughout the 1970s, various health organizations created more awareness of the disease and raised funds for research which significantly improved the quality of life and life expectancy for patients. Significant advances were made including bone marrow transplantation, pneumococcal prophylaxis, hydroxycarbamide and splenic palpitation (Wailoo, 2017). 

Frequency of Disorder 

Costa and Conran (2016) explain that sickle cell anemia is a genetic disease caused by DNA mutations which lead to changes in the hemoglobin. It affects only those people whose ancestors originate from specific areas including Africa, some Mediterranean countries and Saudi Arabia. The frequency of the disease is related to the geographical region, the presence of malaria as well as parental or ancestral genetics of an individual. The primary factor influencing the frequency of the disease is genetics. For an individual to have the disease, both parents must have the gene mutation. Studies show that there is a 25% probability that they will sire a child with the disease and a 50% probability that their child will be a carrier of the illness. 

Ethnic and Gender Differences 

SCD is only prevalent in certain races. The greatest population has its origin in Africa. This can be explained by the fact that the Malaria epidemic is in Africa. Researchers explain that long ago, people who contracted malaria developed the abnormal formation of their red blood cells. In later generations, some individuals carry the trait in their genes and can get the disease once they are infected with malaria. Other races that are affected by SCD include Middle Eastern, Caucasian, and the Mediterranean. Both male and female are equally affected with the disease since they are autosomal regarding the disease meaning that, the sickle cell gene is one of the first 22 chromosomes which do not affect sex (Costa & Conran, 2016) 

Symptoms 

Symptoms vary among individuals (Lervolino & Campos, 2011). One of them is anemia, which results from the high frequency of red blood cell destruction leading to their shortage. Pain episodes/crises also characterize the disease, caused by blood vessels blockage by sickle cells to the abdomen, chest, and joints. There are also the painful swellings on hands and feet as a result of blood vessels blockage by sickle cells to these regions. Frequent infections may occur, emanating from the destruction of the infection-fighting organ; the spleen, by the sickle cells. Delayed growth is also another symptom, due to insufficient oxygen and nutrients that are vital for growth (Lervolino & Campos, 2011). Visual impairment may occur when the veins that supply blood to the eyes get plugged with sickle cells. 

Impact on Individual and Family 

SCD is characterized by frequent, unpredictable pain known as vaso-occlusive crises (VOC’s) which can psychologically affect the patient and their family. The individuals are at risk of maladjustment of all areas of daily life. Research indicates the prevalence of behavioral and emotional problems, poor athletic abilities, poor self-concept, and interpersonal relationships among others (Lervolino & Campos, 2011). The family of individuals with SCD has a difficult time dealing with the care and demand related to the disease due to increased work, stress and financial costs. 

Etiology of SCD 

SCD occurs when there is a mutation in the HBB gene which determines the formation of part of hemoglobin, which is a protein that consists of two alpha chains and two beta chains with an iron-laden “heme” portion that gives the blood its red color. It also enables the hemoglobin molecule to attach to oxygen molecules and then release them. When HBB mutates, it leads to changes in an amino acid in the beta chain of hemoglobin causing it to form stiff rods that alter the disc-shape of the red blood cells to sickle shape, making them more fragile. People with SCD have hemoglobin-S molecule while those without the disease have hemoglobin A-molecule in their blood. It is a hereditary disease that is inherited in an autosomal recessive manner (Lervolino & Campos, 2011). 

Genetic Predispositions 

Sickle cell anemia is inherited in an autosomal recessive manner such that, mutations occur in both copies of the gene in each cell. The parents of an individual with this disorder have one copy of the mutated gene but do not demonstrate any symptoms related to the disease. They are thus said to be sickle cell carriers or having the sickle cell trait. (Costa & Conran, 2016). According to Costa and Conran (2016), people who are carriers have a 25% chance of bearing a child with sickle cell anemia and a 50% chance of bearing a child with the sickle cell trait. 

Treatment Options 

Sickle cell anemia can only be cured through bone marrow transplant, a procedure that is also known as stem cell transplant. The risks involved in this treatment are very high including death and is only recommended for individuals younger than 16 years of age. The major challenge involved is to find a donor, which is very difficult. Due to these reasons, most treatments are done to alleviate painful crises, reduce the symptoms and prevent complications. It is thus advisable for patients to make frequent visits to the doctor. Blood transfusion is also a treatment option that is aimed at providing the patient with red blood cells which may be in acute shortage. Medication includes antibiotics; penicillin to prevent infections, various medications to reduce pain during crises and hydroxyurea to reduce the frequency of painful attacks and the need for blood transfusion (Costa & Conran, 2016). 

Conclusion 

Sickle cell anemia is a disorder of the red blood cells that is inherited from two parents who are carriers of the disease. It was first officially published in 1910, and since then many cases have been reported, significantly contributing to the medical knowledge through research work. This disorder only affects individuals with origins from specific regions including Africa, the Middle East and certain Mediterranean countries with races including Africans, Caucasians, and Mediterranean. Symptoms include anemia, pain episodes, painful swellings of hands and feet, frequent infections, delayed growth as well as vision problems. Both the patient and family members are psychologically affected by the disease. Treatment options include bone marrow transplant, blood transfusions, and the use of antibiotics, pain relievers and hydroxyurea. 

Reference 

Costa, F. F., & Conran, N. (2016).  Sickle cell anemia: From basic science to clinical practice , (6 th ed.). Springer. 

Lervolino, L. G., Baldin, P. E., Picado, S. M., Calil, K. B., Viel, A. A., & Campos, L. A. (2011). Prevalence of sickle cell disease and sickle cell trait in national neonatal screening studies.  Revista brasileira de hematologia e hemoterapia ,  33 (1), 49-54. doi:   10.5581/1516-8484.20110015 

Wailoo, K. (2017). Sickle Cell Disease — A History of Progress and Peril. The New England Journal of Medicine, 2017 (376), 805-807. doi: 10.1056/NEJMp1700101