NSG 530 – Week 9 Reply

Instructions

This is the post for week 9’s reply.

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Sickle cell disease (SCD) is a genetic autosomal recessive disorder that is characterized by a mutation of the gene that is responsible for building hemoglobin. This makes the hemoglobin, Hb S, susceptible to polymerization, which causes the red blood cell (RBC) to transform into a characteristic sickle shape (Steinberg, 2022). This polymerization and resultant sickling, which is reversible, can be triggered by deoxygenation of the hemoglobin and by acidemia (Steinberg, 2022). Sickle cell mutations are far more prevalent in people of Sub-Saharan African descent than in the general population; this is believed to be the case because the heterozygous presence of the allele provides a survival advantage related to the resistance it confers to malaria.

When cells become sickled, this can lead to hemolysis and also to vaso-occlusion, because they are not able to slide through the capillaries and small vessels as effectively as normal RBCs do (Vichinsky, 2022). Vaso-occlusion causes intense pain, both acutely and chronically, owing to tissue ischemia and small vessel infarction (Vichinsky, 2022). Infarction often affects the spleen, making it shrink and lose function, and this in turn is detrimental to the immune system; impaired tissue perfusion and infarction can cause an array of other forms of end-organ damage as well (Vichinsky, 2022).

Hypoxia, illness, inflammation, dehydration, and stress can all lead to increased rates of sickling and episodes of acute pain (Steinberg, 2022). People with SCD acute pain episodes are often stigmatized within the healthcare system in ways that negatively impact the management of their pain; research shows that a majority of physicians do not trust the accuracy of self-reported pain when treating people with SCD and that a majority of nurses believe that people with SCD are likely to develop opioid addiction (Steinberg, 2022). In fact, evidence shows that opioid misuse among people with SCD is actually lower than it is in the general population (Steinberg, 2022).

References

DeBaun, M. R., & Galadanci, N. A. (2022). Sickle cell disease in Sub-Saharan Africa (E. P. Vichinsky & J. S. Tirnauer, Eds.). UpToDate. Retrieved October 27, 2022, from https://www.uptodate.com/contents/sickle-cell-disease-in-sub-saharan-africa

Steinberg, M. H. (2022). Pathophysiology of sickle cell disease (M. R. DeBaun & J. S. Tirnauer, Eds.). UpToDate. Retrieved October 27, 2022, from https://www.uptodate.com/contents/pathophysiology-of-sickle-cell-disease

Vichinsky, E. P. (2022). Overview of the clinical manifestations of sickle cell disease (M. R. DeBaun & J. S. Tirnauer, Eds.). UpToDate. Retrieved October 27, 2022, from https://www.uptodate.com/contents/overview-of-the-clinical-manifestations-of-sickle-cell-disease

 

Response

Hi,

I appreciate the information you provided in your initial discussion regarding the pathophysiology of sickle cell disease including its clinical manifestation and etiology. You provided your discussion in clear and simple terms that are understandable even to a layperson. I have a feeling that the pathophysiology of sickle cell disease is somehow complicated, therefore, the majority of nurses fail to understand it.

I agree with your definition of sickle cell disease as an autosomal disorder that causes mutations of the gene that confers hemoglobin development. Consequently, the hemoglobin HbS becomes vulnerable to polymerization, causing red blood cells to change their character and shape (Inusa et al., 2019). The Idea of pathophysiology was well described by Catherine in her initial discussion.

To add a bit of information on top of what Catherine provided, the inheritance of sickle cell anemia (homozygous HbS) is the most common form of sickle cell disease. The prevalence may vary based on the country of origin (Inusa et al., 2019). The second most common type of sickle cell disease is the co-inheritance of HbS and HbC, also called HbSC. However, the latter is the most prevalent in Western Africa, especially Burkina Faso and Mali.

It is also common in coastal countries such as Benin, Ghana, and Western Nigeria. The core inheritance with β thalassemia caused sickle β thalassemia genotype (HbS/βo or HbS/β+) (Inusa et al., 2019). The process gets more complicated and, hence, requires good time and resources to understand. According to Sundd et al. (2019), sickle cell anemia (often caused by homozygosity of the beta-S (βS) allele) differs from the wild-type β-allele by a single nucleotide polymorphism dbSNP Rs334 (T; T).

In this situation, the GTG is replaced by GAG in the sixth cordon of the β-globin gene. The whole process leads to glutamic acid residue (Glu) being replaced with a hydrophobic valine residue (Val) at the sixth position in the β-globin chain. Inusa et al. (2019) state that sickle cell disease is more common in African, Arab, and Indiana ancestry. The disease affects over 14,000 individuals who suffer from sickle cell disease in the UK and France.

Other countries such as Germany have experienced increasing numbers over the past years. Clinical manifestations of sickle cell disease include pain, anemia, acute aplastic crisis, and others (Sundd et al., 2019). The disease leads to a range of acute and long-term complications that require a multidisciplinary approach to management.

References

Inusa, B. P., Hsu, L. L., Kohli, N., Patel, A., Ominu-Evbota, K., Anie, K. A., & Atoyebi, W. (2019). Sickle cell disease—genetics, pathophysiology, clinical presentation and treatment. International Journal of Neonatal Screening, 5(2), 20. https://doi.org/10.3390/ijns5020020
Sundd, P., Gladwin, M. T., & Novelli, E. M. (2019). Pathophysiology of Sickle Cell Disease. Annual review of pathology, 14, 263–292. https://doi.org/10.1146/annurev-pathmechdis-012418-012838