Sickle Cell Anemia in Adults - Research Paper Example

Sickle Cell Anemia in Adults Abstract Sickle cell anemia or sickle cell disease is a pathological condition that manifests in early infancy. The condition is associated with morbidity and mortality and many children succumb to its complications in childhood and adolescence. Some of them enter into adulthood and suffer from chronic complications related to chronic hemolysis, recurrent infarctions, chronic organ disease and chronic pain. The dreaded complication of the disease in adults are infarction crises which can manifest as dactylitis, femoral head necrosis, acute abdomen, hematuria and stroke. The disease is through autosomal recessive inheritance. Mutation of the HbS gene causes a different type hemoglobin that polymerizes easily and causes sickling of red blood cells. This phenomenon is the root causes of various events that contribute to mortality and morbidity of the disease. The disease is predominant in those living and originating from sub-Saharan region. The disease is predominantly a pediatric age-group disease. Those who survive into adulthood have specific complications making sickle cell disease in adulthood a significant topic to discuss. This essay will discuss about various aspects of sickle cell anemia in adults. Introduction Sickle cell anemia or sickle cell disease and its variants are basically genetic disorders involving hemoglobin (Meremikwu and Okomo, 2011). Persons with these conditions have a mutated form of hemoglobin, known as HbS. The condition leads to anemia and other critical consequences contributing to morbidity and mortality. The condition is mainly seen in Mediterranean and African ancestry. Many adults and children in sub-Saharan region suffer from this disease. The degree of anemia, the frequency of crises, morbidity and involvement of organ systems varies from one individual to another. The most severe form of the disease is seen in homozygous HbS. Vaso-occlusive crisis episodes are seen in more than 50 percent of individuals suffering from homozygous HbS disease. Adults, when compared to children have different clinical presentation (Meremikwu and Okomo, 2011). In this essay, sickle cell anemia in adults will be discussed. Etiology and epidemiology The disease is autosomal recessive. The genetic defect is in the HbS gene (Meremikwu, 2009). HbS mutation arises from a mutation that substitutes thymine for adenine in the 6th codon of the gene of beta chain, GAG to GTG. This change leads to coding of valine instead of glutamate in the 6th position of Hb chain. This type of hemoglobin is known as HbS which polymerizes easily under certain circumstances and alters the morphology of RBCs. Homozygous disease is the most severe form (Meremikwu, 2009). Sickle cell disease is most common in individuals residing in or originating from sub-Saharan Africa. It also affects individuals from Caribbean, Meditteranean, Asian and Middle-eastern origin. "About 60,000 people in the US[ and 10,000 in the UK suffer from the disease" (Meremikwu and Okomo, 2011). "Sickle cell disease (SCD), the most common inherited blood disorder in the United States, is caused by a mutation in the hemoglobin-beta gene found on chromosome 11" (Parsh, 2013). According to Aljiburi et al (2012), "Sickle cell disease (SCD) is the most common inherited blood disorder in England." Pathophysiology and Pathogenesis The abnormality in sickle cell disease lies in the hemoglobin. The molecule is mutated and is known as HbS. When deoxygenated, the HbS molecules polymerize to form psuedocrystalline structures called tactoids. These distort the red cell membranes making them form a characteristic sickle cell appearance. When reoxgenated, the polymerisation is actually reversible. However, on some occasions, the distortion of the cells may become irreversible and this leads to permanent sickling of cells. Sickling of cells mainly occurs in regions of microvasculature where blood flow is sluggish. Sickled cells increase the viscosity of the blood and tend to obstruct the flow of blood in capillaries leading to tissue infarction and thrombosis. This leads to severe pain, tenderness and inflammation of the affected area and this is known as infarction crisis (Dorman, 2005). The lifespan of the blood cells also decrease resulting hemolysis. Sickle cells adhere to macrophages and this leads to erythrophagocytosis and hemolysis. During sickling, the RBCs gain Na+ and lose K+ along with increased permeability to calcium. This probably is because of impairment in ATPase pump and calcium pump (Meremikwu and Okomo, 2011). This alters the morphology of the cell membrane contributing to sickling. Factors which contribute to sickling in adults are dehydration, local tissue hypoxia, acidosis, fatigue, exposure to cold, stress of any form, alcohol intoxication and pregnancy. Acute chest syndrome is related to infections, fat embolism, asthma and painful episodes (Meremikwu, 2009). Clinical presentation In adults, clinical presentation varies from one individual to other (Jenerette, & Phillips, 2006). More often than not, the diagnosis is already made in childhood. Rarely, the adult patient presents with repeated joint pains and anemia. Other features include anemia, jaundice, repeated infarction crises, shock, sepsis and acute and chronic pain. Hematological changes suggestive of sickle cell disease can manifest as early as 10 weeks of age. However, symptoms appear only after 6- 12 months of age. This is because; until then, high levels of fetal hemoglobin are present which prevent sickling of cells. Multiorgan involvement can be there manifesting as anatomical and functional alterations of the kidney, and enlargement of spleen and liver. Patients can develop life-threatening bacterial infections due to altered immunoglobin levels and opsonization. Pneumococcal sepsis is common and infection with parvo virus B19 can lead to aplastic crises. Splenomegaly occurs after one year of age and sometimes pooling of large number of sickle cells in the spleen can lead to sudden painful splenomegaly known as splenic sequestration. Low pH levels in blood and low oxygen tension can lead to repeated infarcts in the spleen leading to fibrosis and shrinkage. This is known as autosplenectomy. Infarction crises are characterized by severe acute pain making the life of the patient miserable. Most commonly, the episodes involve the bone and spleen but any involve any tissue. Mesenteric infarction can lead to abdominal emergency. Another important site of damage is the renal papilla and this manifests as painless hematuria. Aseptic necrosis of the femur in adults is a disabling condition. Acute chest syndrome is also common among adults and is probably due to pulmonary infarction but resembles pneumonia. The risk of stroke is high among adults and can be recurrent (Strosse et al, 2011). Pregnancy is a hazardous phase and antenatal care must be meticulous because of risk of bone marrow emboli and fat emboli as term approaches. Bone infarction is also common and manifests as dactylltis and osteomyelitis. In adults, infarction mainly occurs in the subchondrium and diaphyses of the long bones. Osteonecrosis of both femoral heads can lead to collapse of femoral heads (Maremikwu and Okomo, 2011). In adults, gall stone disease. Adults may have skull bossing and other features of chronic hemolytic anemia. They are usually short due to stunted growth (Jenerette, and Lauderdale, 2008). They frequently have hepatosplenomegaly, leg ulcers and cardiomegaly and present to hospital settings in cardiac failure (Meremikwu and Okomo, 2011). Differential diagnosis The diagnosis of sickle cell anemia is confirmed by electrophoresis when it demonstrates homozygous HbS (Meramikwu, 2009). It can also be associated with other hemoglobinopathies like beta-thalassemia and electrophoresis confirms this too. Another variant is the heterozygous condition, the HbSC. It is a milder sickling disease. Splenomegaly can persist into adulthood in this condition. Laboratory work up In the United States, children are screened at birth for HbS. In suspected cases, prenatal diagnosis is also possible though chorionic villous sampling. Hb electrophoresis is the diagnostic test for homozygous and also variants of sickle cell disease. When patients are admitted in crises, complete blood picture, ABG and other tests are done based on clinical presentation (Meremikwu and Okomo, 2011). Treatment Patients with sickle cell disease need appropriate optimal and preventive care. A hematologist must be involved along with primary care physician. In conditions where severity of crises can be assessed treatment can be initiated at home and it involves appropriate hydration and oral analgesia (Lee et al, 2012). It is very important to recognize and treat acute pain because, failure to do so can lead to chronic pain syndrome (Meremikwu and Okomo, 2011). Severe cases must be transported to the hospital in an ambulance and intravenous fluids and hydration must be initiated enroute to the hospital. The goals of symptom management in sickle cell anemia are management of various chronic pain syndromes, chronic hemolytic anemia, vaso-occlusive crises, prevention and treatment of infections, management of organ damage syndrome, prevention of stroke, early detection and management of pulmonary hypertension and appropriate vaccination. The cure for sickle cell disease is allogenic bone marrow transplantation (Hsieh et al, 2011). Since there are several risks associated with transplantation, it is recommended only to those who are not responding well to conservation management. One of the limiting factors for bone marrow transplantation is lack of availability of matched donor. In specific conditions, hydroxyurea therapy, antibiotics, blood transfusions and others may be necessary. Drugs which are mainly used in the treatment of sickle cell disease are analgesics, antimetabolites, vaccines and antibiotics (Hsieh et al, 2011). Conclusion Sickle cell anemia in adults manifests as chronic hemolytic anemia, repeated infarction crises, chronic pain and jaundice. The adults are short due to poor growth and have frontal bossing. They may suffer from other complications like gall stones, stroke and pulmonary hypertension. References Aljuburi, G., Okoye, O., Majeed, A., et al. (2012). Views of patients about sickle cell disease management in primary care: a questionnaire-based pilot study. J R Soc Med Sh Rep., 3 (11), 78. Dorman, K. (2005). Sickle cell crisis! Managing the pain. RN, 68(12), 33-36. Hsieh, M.M., Fitzhugh, C.D., Tisdale, J.F. (2011). Allogeneic hematopoietic stem cell transplantation for sickle cell disease: the time is now. Blood, 118(5), 1197-207. http://bloodjournal.hematologylibrary.org/content/118/5/1197.long Jenerette, C., & Phillips, R. (2006). An examination of differences in intra-personal resources, self-care management, and health outcomes in older and younger adults with sickle cell disease. Southern Online Journal of Nursing Research,3(7), 1-24. Jenerette, C.M., and Lauderdale, G. (2008). Successful Aging with Sickle Cell Disease: Using Qualitative Methods to Inform Theory. J Theory Constr Test., 12(1), 16–24. Lee, L., Askew, R., Walker, J., et al. (2012). Adults with Sickle Cell Disease: An Interdisciplinary Approach To Home Care and Self-Care Management With a Case Study. Home Healthcare Nurse, 30(3), 172- 183. Meremikwu, M.M., Okomo, U. (2011). Sickle cell disease. Clin Evid (Online). Retrieved on 6th April, 2013 from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3217656/ Meremikwu MM. (2009). Sickle cell disease. Clin Evid (Online). Retrieved on 6th April, 2013 from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2907800/ Parsh, B. (2012). Understading sickle cell disease. Nursing, 42, 8, p.64 Strouse, J.J., Lanzkron, S., Urrutia, V. (2011). The epidemiology, evaluation and treatment of stroke in adults with sickle cell disease. Expert Rev Hematol., 4(6), 597-606 Read More