Sickle cell disease (SCD) is a group of autosomal recessive disorder characterized by the production of hemoglobin S (Hb S; sickle hemoglobin) within the erythrocytes. The Hb S is formed due to a genetic mutation in which one amino acid (valine) replaces another (glutamic acid) Huether et. al., (2020 p. 551). Sickle cell disease (SCD) is a group of inherited disorders caused by mutations in Beta Globin-related Hemoglobinopathies (HBB), which encodes hemoglobin subunit β. The incidence is estimated to be between 300,000 and 400,000 neonates globally each year, the majority in sub-Saharan Africa Kato, Piel & Reid et al., (2018).
Hemoglobin molecules that include mutant sickle β-globin subunits can polymerize; erythrocytes that contain mostly hemoglobin polymers assume a sickled form and are prone to hemolysis. Sickle cell disease is characterized by red blood cells that assume an abnormal, rigid, sickle shape Ilesanmi (2018). The Hb S is soluble and there is no problem when it has enough oxygen, but it is a problem when there is low oxygen supply (hypoxemia), PH and dehydration. These causes the Hb S to sickle, hemolysis of the red blood cells occurs, the sickled erythrocytes make the blood viscous leading to vascular occlusion, pain and organ infarction. Poor oxygenation some time causes hemolysis of the hemoglobin in the spleen or sequestration, blood pooling, infarction of the spleen, this leads to erythropoiesis in the bone marrow due to anemia and sometimes in the liver when severe Huether et. al., (2020 p. 553).
Sickle cell disease does not manifest until at the age of 6 months old and this is time that postnatal concentration of hemoglobin F is reduced, causing the concentration of Hb S to increase. The clinical manifestations include pallor, fatigue, jaundice, and irritability as a result of hemolysis. When there is severe hemolysis, it could cause acute crisis such as:
1. Vaso-oclussive crisis (thrombotic crisis): This crisis starts with the smallest blood vessels, as the blood flow is blocked through the vessels causing spasms and pain. When this occur in the brain it may result to stroke and if it is in the kidney it will cause end-stage renal disease Huether et. al., (2020 p. 553).
2. Sequestration crisis: This type of crisis is seen in children less than 5 years. This is a condition where large amount of blood is pulled to the spleen and liver, if not corrected it can cause death Huether et. al., (2020 p. 554). Crizanlizumab, a P-selectin inhibitor, was approved by the FDA in November 2019 to reduce frequency of vaso-occlusive crisis (VOC) in adults with sickle cell disease. Binding P-selectin on the surface of activated endothelium and platelet cells blocks interactions between endothelial cells, platelets, red blood cells, and leukocytes Maakaron, (2020).
3. Aplastic crisis: Profound anemia that is caused by the lowered erythropoiesis even though there is need for new erythrocytes. In sickle cell the erythrocytes survive 10 to 20 days, the bone marrow manufactures and replaces it but when there is infection such as viral infection, aplastic crisis occurs Huether et. al., (2020 p. 554).
Hyperhemolytic crisis: It may occur due to certain drugs or infections. It could be acute or chronic due to blood transfusion Huether et. al., (2020 p. 554).
The methods of diagnosis of sickle cell disease differs with age of the person, but there are four tests done to detect SCD or prevent children born with this condition. These are done preconception, prenatal, neonatal and post-neonatal. The testing is done to identify potential of parents giving birth to children with SCD. The laboratory testing uses protein chemistry to separate Hb species to their protein structure, Hb electrophoresis, high-performance liquid chromatography (HPLC) and isoelectric focusing Kato, Piel & Reid et al. (2018). Couple that test positive during this screen may opt for in vitro fertilization with pre-implantation genetic diagnosis before the embryo is transferred to the mother Kato, Piel & Reid et al. (2018).
The prenatal is done at 9 weeks of pregnancy and it is an invasive test. It done for couple that tested positive during preconception screen. It requires fetal DNA samples collected from the chorionic villus analysis Kato, Piel & Reid et al. (2018).
The newborn screening is done at birth before symptoms occur. There are in two ways, selective screening for infants born by high risk parents and universal screening which identifies newborn babies with the SCD, and this helps to initiate treatments and precautions to prevent infections and deaths Kato, Piel & Reid et al. (2018).
Post-neonatal testing requires the testing for SCD and tis is mostly done on immigrant at risk older patients that has not been tested before but at risk for SCD but attended clinic for family planning Kato, Piel & Reid et al .The knowledge of one’s is sickle cell carrier (HbAS) is good to help in family planning to avoid having a baby with SCD.
The treatments of patient with sickle cell disease is comprehensive and usually to help control pain, reduce complications and increase life expectancy. The administration of hydroxycarbamide which is a ribonucleotide reductase inhibitor. This helps to increase fetal hemoglobin (HbF). This drug reduces incidences of sickle cell anemia in vaso-occlusive crises, hospitalizations and mortality Kato, Piel & Reid et al. (2018).
Erythrocyte transfusion improves microvascular flow by reducing the number of circulating sickle erythrocytes and it helps to reduce endothelial injury and inflammatory injury
Hematopoietic stem cell transplantation is used to cure SCD. Usually the human leukocyte antigen (HLA)-matched family donor. Survival of patients in USA and Europe had exceeded 90% according to studies Kato, Piel & Reid et al. (2018).
The National Herat, lung, and Blood Institute instituted guidelines on how the treatment of SCD patients on experiencing Vaso-occlusive crisis. Pain management therapy should be initiated within 30 minutes of arrival to the emergency or 60 minutes of registration. Pain medication should be based on the patient’s SCD provider or an SCD protocol. In severe pain, morphine should be started per intravenous, or subcutaneously if unable to access vein, dosage should be calculated according home opioid use and morphine dosage should individualized. Pain reassessment every 15-30 minutes and opioid dosage re-adjusted according to pain scale. Opioid may be administered round the clock using PCA and monitor for sedation. Opioid should be titrated before discharging home and short-acting opioid ordered to prevent withdrawal. Do not use meperidine unless it is the only effective opioid for that patient. Use oral NSAIDs as an adjuvant analgesic, unless contraindicated
Prescribe oral antihistamines for patients who require these agents for itching from opioids; give repeat doses every 4-6 hours, if needed, rather than with each dose of opioid Maakaron (2020).
After this 38 years African American woman pain has been stabilized, vital signs should be reassessed to check the status of her heart rate and blood pressure which was elevated to see if her medications should be adjusted before discharged or if the elevations were due to pain. Hematocrit level should be rechecked to evaluate if patient requires blood transfusion. Empirical antibiotics depending if infection was detected administered according to the causative organism, or antiviral if the infection was due to virus infection.
Patient should be encouraged to modify her diet by eating meat, fish, eggs, broccoli, green leafy vegetables, nuts, green beans, fruits and drinking plenty of fluids to prevent dehydrations. Patient should be advised to follow up with her primary doctor for sickle cell disease after discharge.
Reference
Huether, S. E., McCance, K. L., & Brashers, V. L. (2020). Understanding Pathophysiology (7th ed.). Mosby/Elsevier
Joseph E Maakaron, M. (2020, August 21). Sickle Cell Anemia Treatment & Management: Approach Considerations, Hydroxyurea Therapy, Transfusion. Retrieved from https://emedicine.medscape.com/article/205926-treatment#d12
Kato, G., Piel, F., Reid, C. et al. Sickle cell disease. Nat Rev Dis Primers 4, 18010 (2018). https://doi.org/10.1038/nrdp.2018.10
Ilesanmi O. O. (2010). Pathological basis of symptoms and crises in sickle cell disorder: implications for counseling and psychotherapy. Hematology reports, 2(1), e2. https://doi.org/10.4081/hr.2010.e2
