The Pathophysiological Processes of Sickle Cell Anemia

Introduction 

Sickle cell anaemia is one of the most common types of genetic illness in the world causing many deaths in many parts of the world. It is a disease that is characterized by the presence of sickle or abnormal hemoglobin that is inherited from parents. The presence of abnormal hemoglobin leads to a distortion in red blood cell. The sickled red blood cells are always weak or fragile and can easily rupture, leading to a significant decrease in the number of red blood cells in affected person. A reduction in red blood cells due to hemolysis is what causes anaemia, hence the name sickle cell anaemia. Sickle cell anaemia is an inherited disease that occurs when sickle cell gene is inherited from both parents. However, the inheritance of sickle cell gene from one parent does not lead to sickle cell anaemia. Even though only 1% of the global population has sickle cell anaemia, it is estimated that about 300,000 children are annually diagnosed with the diseases (Makani et al ., 2013). The majority of cases of sickle cell anaemia, about 75%, are found in Sub-Saharan Africa. Therefore, sickle cell anaemia is a common disease that is claiming lives of many people the word, especially in Africa.

Etiology and Risks Factors

Sickle cell anaemia is caused by inheriting sickle or abnormal hemoglobin from both parents who are sickle cell carriers. The abnormal hemoglobin causes distortion in the normal red blood cells, leading to anaemia (Makani et al ., 2013). Hence, it is a condition that occurs when red blood cells that contain abnormal hemoglobin becomes rigid and is ruptured to form a crescent-like shape. The change in the shape of red blood cells prevents them from entering into small blood vessels, making the tissues to lack enough oxygen. Sickle cell anaemia is a condition that is inherited from both parents and it is a genetic disease. Unlike normal red blood cell that has a lifespan of about 120 days, sickled red blood cells die within 20 days, making the blood to be chronically short of red blood cells, causing anaemia (Makani et al ., 2013). Generally, sickle cell anaemia is caused by sickle or abnormal hemoglobin, which is one of the most essential components of red blood cells.

Sickle cell anaemia is a genetic condition that mainly affects Africans and African Americans. It is estimated that about 75% of people who are suffering from the disease are found in Sub-Saharan Africa (Makani et al ., 2013). In the USA, the majority of people with sickle cell anaemia are African Americans. Sickle cell anaemia equally affects both men and women in the society. However, the morbidity is higher in males than in females. For instance, the medium age for the death of men with sickle cell anaemia is 42 while that of women in 48. At the same time, sickle cell anaemia is found in people of all ages, especially those below 45 years old. Diagnosing children below four years with sickle cell anaemia is possible. Besides, people with chronic diseases and those facing constant stress are likely to be diagnosed with sickle cell anaemia. Moreover, lack of healthy diet and physical exercise are some risk factors for sickle cell anaemia (Tewari et al ., 2015). Some studies have also found that people who live in extreme hot or cold areas have higher risks of developing sickle cell anaemia than individuals in warm geographical locations.

Pathophysiological Process

Hemoglobin is an essential cellular component of red blood cells that transport oxygen in the blood to various parts of the body. However, the chances of suffering from sickle cell anaemia are increased when the shape of hemoglobin changes from flat –disc-shaped cells to a sickle-shaped cell (Makani et al ., 2013). Sickle cell anaemia starts with the formation of sickle hemoglobin in the red blood cell. The gene mutation that leads to sickle hemoglobin is incorporated as a substitution of thymine for adenine on the sixth codon of the genetic sequence. It is the genetic alteration that leads to a change in the shape of hemoglobin cells (Makani et al ., 2013). At the same time, the change in the shape of hemoglobin makes red blood cells to be in sickle-like shape. Sickle hemoglobin cells lead to the damage of the red blood cells, especially after erythrocyte has been damaged permanently. Consequently, this leads to red cells dehydration and deoxygenating, resulting in chronic anaemia or sickle cell anaemia.

The body tries to overcome sickle cell anaemia mainly through the re-oxygenation of the affected red blood cells. Red blood cells temporarily go through the re-oxygenation process to resume its regular shape (Makani et al ., 2013). However, the repeated cycle of re-oxygenation leads to permanent damage of erythrocyte. The symptoms and signs of sickle cell anaemia start to emerge after erythrocyte is permanently damaged.

Clinical Manifestations and Complications

The primary clinical manifestations of sickle cell anaemia include painful events and splenic dysfunction, as well as acute chest syndrome. Painful events manifest due to ischemic tissue injuries and dehydration (Maitra et al ., 2017). Musculoskeletal pain is common among patient with sickle cell, and abdominal pain always follows it. Splenic dysfunction, on the other hand, is common during infancy. At the same time, stroke is one of the clinical manifestations among patients with sickle cell anaemia. It is estimated between 6% and 12% of people with sickle cell anaemia experience stroke (Maitra et al ., 2017). Cerebral infarction is the leading cause of stroke among children with sick cell anaemia.

Hyperhemolysis crisis is the main complication that is associated with sickle cell anaemia. The complexity is caused by the sudden decline in the state of hemoglobin as well as increased reticulocytosis. Also, chronic haemolysis can lead to gallbladder diseases because of the increased level of bilirubin (Maitra et al ., 2017). Besides, patients with sickle cell anaemia are susceptible to various types of infections. Therefore, the disease has many complications. 

Diagnostics

Diagnosis of sickle cell anemia is mainly based on the demonstration of the presence of sickle hemoglobin in the blood (Makani et al ., 2013). Many physicians use blood tests, mainly through the utilization of hemoglobin electrophoresis to determine whether abnormal hemoglobin is present in the blood. Screening tests through the use of sodium metabisulphite are common in many developing countries, particularly in Africa. The sickle solubility test is also a common diagnostic technique used by physicians to diagnose sickle cell anemia (Makani et al ., 2013). Studies have shown that additional confirmatory tests should be conducted when the screening assays used. Confirmatory tests help in validating results from screening tests. 

Conclusion

Sickle cell anaemia is a genetic condition that affects many people in various parts of the world. However, the disease is common in African countries and among African American. Individuals with sickle anaemia can hardly live beyond 50 years, which is an indication that it is one of the deadly diseases. Therefore, early diagnosis and effective disease management techniques should be used to reduce the impact of sickle cell anaemia in the society.

References

Maitra, P., Caughey, M., Robinson, L., Desai, P. C., Jones, S., Nouraie, M. ... & Ataga, K. I. (2017). Risk factors for mortality in adult patients with sickle cell disease: a meta-analysis of studies in North America and Europe. Haematologica , 102(4), 626-636.

Makani, J., Ofori-Acquah, S. F., Nnodu, O., Wonkam, A., & Ohene-Frempong, K. (2013). Sickle cell disease: new opportunities and challenges in Africa. The Scientific World Journal , 3(1), 1-16.

Tewari, S., Brousse, V., Piel, F. B., Menzel, S., & Rees, D. C. (2015). Environmental determinants of severity in sickle cell disease. Haematologica , 100 (9), 1108-1116.