Sickle Cell Anemia PDF

Sickle Cell Anemia What is Sickle Cell Anemia? Sickle cell anemia is a hereditary blood disorder characterized by the production of abnormal hemoglobin, called hemoglobin S, in red blood cells. This abnormal hemoglobin causes the red blood cells to become rigid, sticky, and shaped like a...

Sickle Cell Anemia What is Sickle Cell Anemia? Sickle cell anemia is a hereditary blood disorder characterized by the production of abnormal hemoglobin, called hemoglobin S, in red blood cells. This abnormal hemoglobin causes the red blood cells to become rigid, sticky, and shaped like a crescent or sickle, rather than the typical flexible, round shape.  Disease Etiology Sickle hemoglobin (HbS) is a structural variant of normal adult hemoglobin (HbA) caused by a missense variant in the β-globin gene (HBB) that causes substitution of valine for glutamic acid at position 6 of the β- globin subunit (βS) of the hemoglobin molecule. Sickle cell disease (SCD) refers to a group of disorders characterized by the presence of at least one βS allele and a second HBB variant that results in the predominant production of HbS. Its most common form is due to Inheritance It is inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the mutated gene (one from each parent) to have the disease. People with only one copy of the mutated gene are carriers (sickle cell trait) and usually do not exhibit symptoms. Pathogenesis Hemoglobin is composed of four subunits: two α subunits encoded by HBA on chromosome 16 and two β subunits encoded by HBB on chromosome 11. The p.Glu6Val variant in β-globin decreases the solubility of deoxygenated hemoglobin and causes it to form a gelatinous network of stiff fibrous polymers (polymerization), distorting the red blood cell, giving it a sickle shape. These sickled erythrocytes occlude capillaries and postcapillary venules and cause vasoocclusion and infarctions. Initially, oxygenation causes the hemoglobin polymer to dissolve and the erythrocyte to regain its normal shape; however, repeated sickling and unsickling produce irreversibly sickled cells that are removed from the circulation by the spleen. Phenotype Anemia Splenomegaly Repeated infections Dactylitis (painful swelling of the hands or feet from the occlusion of the capillaries in small bones). Vasoocclusive infarctions occur in many tissues, causing strokes, acute chest syndrome, renal papillary necrosis, autosplenectomy, leg ulcers, priapism, bone aseptic necrosis, and visual loss. Bone vasoocclusion causes painful “crises” and, if untreated, these painful episodes can persist for days or weeks. Phenotype Heterozygotes for the variant (who are said to have sickle cell trait) do not have anemia and are usually clinically normal. Under non-physiologic conditions of severe hypoxia, however, erythrocytes of individuals with sickle cell trait may sickle and cause symptoms similar to those observed with SCD. With extreme exertion and dehydration, there is increased risk for rhabdomyolysis in sickle cell heterozygotes. Management and Treatment Pain management: Using medications and other therapies. Blood transfusions: To reduce the number of sickle cells and increase the number of normal red blood cells. Hydroxyurea: A medication that can reduce the frequency of pain episodes and acute chest syndrome. Bone marrow or stem cell transplant: The only potential cure, typically used in severe cases. Preventive care: Including vaccinations and antibiotics to reduce the risk of infections, and regular monitoring for complications. Diagnosis Blood tests: To check for abnormal hemoglobin (hemoglobin electrophoresis) and to count red blood cells. Genetic testing: To identify mutations in the HBB gene. Newborn screening: Often includes testing for sickle cell disease.  Oral Manifestations of Sickle Cell Anemia 1.Mucosal Pallor: The oral mucosa may appear pale due to anemia. 2.Delayed Eruption of Teeth: There can be a delay in the eruption of primary and permanent teeth. 3.Bone Changes: "Stepladder" trabecular pattern in the jawbones and generalized osteoporosis due to marrow hyperplasia. 4.Orofacial Pain: Pain in the face and jaw, often related to sickle cell crises or bone infarctions. 5.Increased Susceptibility to Infections: Due to impaired immune function, patients may have a higher risk of oral infections such as periodontitis. 6.Gingival Enlargement: Due to extramedullary hematopoiesis or use of medications. 7.Ulcerations and Tissue Necrosis: Recurrent oral ulcers and areas of tissue necrosis can occur due to reduced blood flow.  Dental Management of Sickle Cell Anemia Patients 1.Medical History and Consultation: - Obtain a comprehensive medical history, including the severity of the disease, frequency of crises, and any complications. - Consult with the patient’s hematologist to understand the patient's condition and any specific precautions needed. 2.Preventive Care: - Emphasize good oral hygiene practices to prevent infections. - Schedule regular dental check-ups to monitor and maintain oral health. 3.Pain Management: - Use appropriate analgesics to manage dental pain, avoiding medications that may trigger a sickle cell crisis. - Nitrous oxide-oxygen sedation can be considered but should be used cautiously. 4.Hydration: - Ensure the patient is well-hydrated before, during, and after dental procedures to prevent sickling. 5.Stress Reduction: - Minimize stress and anxiety during dental visits to avoid triggering a sickle cell crisis. - Consider short, morning appointments to reduce fatigue and stress. 6.Use of Local Anesthesia: - Use local anesthesia with vasoconstrictors cautiously and in minimal amounts to avoid reduced blood flow.  Dental Management of Sickle Cell Anemia Patients 7. Infection Control: - Maintain strict infection control practices to prevent infections. - Prophylactic antibiotics may be considered for invasive dental procedures, in consultation with the patient’s physician. 8. Avoid Hypoxia: - Avoid procedures that may reduce oxygen levels, such as long appointments without breaks or the use of rubber dams without adequate oxygenation. 9. Management of Dental Infections: - Promptly treat any dental infections to prevent systemic involvement. - Use appropriate antibiotics, avoiding those that may trigger hemolysis in G6PD-deficient patients (a condition sometimes associated with sickle cell anemia). 10. Orthodontic Treatment: - Orthodontic treatment can be performed but requires careful planning and monitoring due to the increased risk of osteonecrosis and delayed healing. 11. Emergency Care: - Be prepared to manage acute dental emergencies and coordinate care with the patient's medical team. 12. Patient Education: - Educate patients about the importance of maintaining oral hygiene and regular dental visits. - Provide information on how to manage oral pain and recognize signs of infection or other complications. References Thompson & Thompson Genetics and Genomics in Medicine, 9th Edition Ashley, C., & Carew, C. (2008). Oral health and sickle cell disease. The Journal of Dental Hygiene, 82(4), 27-31. American Academy of Pediatric Dentistry. (2020). Guideline on Management of Dental Patients with Special Health Care Needs. Pediatric Dentistry, 42(6), 338-343. National Heart, Lung, and Blood Institute. (2014). Evidence-Based Management of Sickle Cell Disease: Expert Panel Report, 2014. National Institutes of Health. Williams, T. N. (2016). Clinical management of sickle cell disease. Hematology, 2016(1), 58-65.