Sickle Cell Symptom #2 - Infections : Effects and Prevention

Continuing our discussion on infection, last week we found out why Sickle Cell Warriors are highly predisposed to infections.If you missed it, you can read it HERE.

Speaking from personal experience, infections are no fun. The body becomes very sluggish and crisis ensues. Afterwhich many Sickle Cell Warriors fall ill admitted in hospital, pumped full of antibiotics. When an infection enters the body, the sickle cell warrior is compromised. What I mean to say is, the body directs all its defenses and energies towards destroying the foreign pathogen making it vulnerable and weak.

Borrowing from Catherine Booth, Baba Inusa and Stephen K. Obaro who wrote an article about infection and Sickle Cell on the International Journal of Infectious Diseases, they tell us what an infection does to the body of a Sickle Cell Warrior.

They say that, during infection with any pathogen, changes occur at a cellular level, which predispose to crises. Levels of circulating leukocytes and inflammatory cytokines increase, with elevated expression of adhesion molecules on both the blood vessels and leukocytes themselves. This occurs locally in infected tissues and systemically. Local acidosis and hypercapnia (increased CO2) in areas of inflammation increases the Hb oxygen, promoting unloading of oxygen from Hb and thus increasing sickling.

The sickling process is initially reversible when HbS is reoxygenated, but dehydration of RBCs increases HbS concentration, promoting extensive polymerization (cell adherence) and causing irreversible membrane damage. These poorly deformable dense cells contribute particularly to vaso-occlusion (vessel obstruction), adhering readily to leukocytes (white blood cells) and endothelium, and also undergo hemolysis (Red blood cell destruction).

In addition, infections can have more non-specific effects on the host physiological milieu, which increase the risk of sickling. Fever with water loss due to sweating, anorexia, and nausea with reduced oral fluid intake, diarrhea, and vomiting all contribute to dehydration. Renal impairment in SCD causes poor urinary concentrating ability, so plasma osmolarity (osmotic concentration) can rise, promoting RBC dehydration. The stress and emotional response, accompanied by neural and hormonal changes, may also play a role.

Sickle Cell Anaemia Infection Prevention #10003

Common pathogens associated with infection in sickle cell anemia with underlying mechanisms for predisposition

Pathogen and Predisposing factors

Encapsulated bacteria (e.g., Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Salmonella spp) - Impaired splenic function & Impaired opsonization (bacteria destruction)

·         Salmonellae               - Recurrent vaso-occlusion with intestinal infarct, necrosis and increased gut                                           permeability & Decreased neutrophil (white blood cell) killing
·         Malaria                - Decreased deoxyhemoglobin solubility
·         Parvovirus           - Increased red cell turnover
·         Hepatitis B, C      - Multiple blood transfusion
·         Chlamydophila    - Unknown
·         Yersinia enterocolitica - Iron overload
·         Mycoplasma        - Unknown
Edwardsiella tarda - Increased intestinal permeability and biliary sludging

Prevention

Simple general measures are important in reducing the risk of infection, though the aim is to ensure as normal a lifestyle as possible. Meticulous attention to hygiene, particularly hand-washing, is vital, and to protect against Salmonella, patients are advised to cook food thoroughly, particularly chicken and eggs, keep items refrigerated, and avoid contamination. Nutritional supplementation with zinc has been reported to reduce infection risk, improve growth rates in SCD children, and possibly improve skeletal and sexual maturation as well as having psychological benefits. Early identification of infections is another key area, enabling prompt initiation of treatment to reduce complications. Parents are encouraged to monitor their children closely at home and seek advice if they have a fever or respiratory symptoms, while maintaining good hydration. There should be a low threshold for the use of antibiotics in ill children with SCD, particularly in the presence of chest signs or symptoms, which may herald ACS(Acute Chest Syndrome).

I hope behind the biological jargon, you all learned something. I promise to make it easier to digest next time. If there is any question or comment with regards to infection and sickle cell, post it below on the comment section.

Otherwise, until next time. Stay healthy and,


Love Life!
Lea

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