Overwhelming post-splenectomy infection

An overwhelming post-splenectomy infection (OPSI) or Overwhelming post-splenectomy sepsis (OPSS)[1] is a rare but rapidly fatal infection occurring in individuals following removal of the spleen. The infections are typically characterized by either meningitis or sepsis, and are caused by encapsulated organisms including Streptococcus pneumoniae.[2]

Another source of infection[3] are varieties of babesia, which are tick-borne parasites that cause babesiosis.[4] Capnocytophaga canimorsus can trigger infection after dog bites.[5]

The risk of OPSI is 0.23–0.42 percent per year, with a lifetime risk of 5 percent.[6] Most infections occur in the first few years following splenectomy, but the risk of OPSI is lifelong.[2][7] OPSI is almost always fatal without treatment, and modern treatment has decreased the mortality to approximately 40–70 percent.[2][8] Individuals with OPSI are most commonly treated with antibiotics and supportive care.[6] Measures to prevent OPSI include vaccination and prophylactic antibiotics.[6][9][10]

Mechanism

The spleen contains many macrophages (part of the reticuloendothelial system), which are immune cells that phagocytose (eat) and destroy bacteria. In particular, these macrophages are activated when bacteria are bound by IgG antibodies (IgG1 or IgG3) or the complement component C3b. These types of antibodies and complement are immune substances called opsonizers, molecules that bind to the surface of bacteria to facilitate phagocytosis.

When the spleen is no longer present (asplenia), IgG and C3b are still bound to bacteria, but they cannot be removed from the blood circulation due to the loss of the splenic macrophages. Hence the bacteria are free to cause infection.

Patients without spleens often need immunizations against pathogens that normally require opsonization and phagocytosis by macrophages in the spleen. These include common human pathogens with bacterial capsules (Streptococcus pneumoniae, Salmonella typhi, Neisseria meningitidis, E. coli, Hemophilus influenzae, Streptococcus agalactiae, Klebsiella pneumoniae). Capsules made of polysaccharides (sugars) permit bacteria to evade phagocytosis by macrophages alone, since only proteins are directly recognized by macrophages in phagocytosis. So humoral immunity in forms of IgG and complement proteins is the human immune system's response against bacterial capsules.

Vaccination

The Centers for Disease Control and Prevention's annual vaccine recommendations includes specifics for individuals without a functioning spleen.[11]

The Centers for Disease Control and Prevention endorses these vaccines for persons with asplenia: http://www.immunize.org/catg.d/p4047.pdf[12]

CureSearch for Children's Cancer has published a wallet card that one can print out and carry. The card indicates the risk; need for medical attention to include parenteral antibiotics when a fever is 101 °F; and suggested management: http://www.survivorshipguidelines.org/pdf/SplenicPrecautions.pdf (p. 4)

References

  1. ↑ surgical recall, seventh edition, lorne H. Blackbourne, page 469.
  2. 1 2 3 Waghorn DJ (March 2001). "Overwhelming infection in asplenic patients: current best practice preventive measures are not being followed". Journal of Clinical Pathology. 54 (3): 214–8. doi:10.1136/jcp.54.3.214. PMC 1731383. PMID 11253134.
  3. ↑ Rosner, F. (April 1984). "Babesiosis in splenectomized adults. Review of 22 reported cases". American Journal of Medicine. 76 (4): 696–701. PMID 6424470.
  4. ↑ Centers for Disease Control and Prevention. "About Babesiosis". CDC Parasites. Retrieved 19 June 2018.
  5. ↑ Sinwar, Prabhu (December 2014). "Overwhelming post splenectomy infection syndrome – Review study". 12 (12): 1314–1316. doi:10.1016/j.ijsu.2014.11.005.
  6. 1 2 3 Davidson RN, Wall RA (December 2001). "Prevention and management of infections in patients without a spleen". Clinical Microbiology and Infection. 7 (12): 657–60. doi:10.1046/j.1198-743x.2001.00355.x. PMID 11843905.
  7. ↑ Cullingford GL, Watkins DN, Watts AD, Mallon DF (June 1991). "Severe late postsplenectomy infection". The British Journal of Surgery. 78 (6): 716–21. doi:10.1002/bjs.1800780626. PMID 2070242.
  8. ↑ Schwartz PE, Sterioff S, Mucha P, Melton LJ, Offord KP (November 1982). "Postsplenectomy sepsis and mortality in adults". Journal of the American Medical Association. 248 (18): 2279–83. doi:10.1001/jama.248.18.2279. PMID 7131680.
  9. ↑ "Guidelines for the prevention and treatment of infection in patients with an absent or dysfunctional spleen. Working Party of the British Committee for Standards in Haematology Clinical Haematology Task Force". BMJ. 312 (7028): 430–4. 1996. doi:10.1136/bmj.312.7028.430. PMC 2350106. PMID 8601117.
  10. ↑ Davies JM, et al. (2001-06-02). "The prevention and treatment of infection in patients with an absent or dysfunctional spleen - British Committee for Standards in Haematology Guideline up-date". BMJ. 312 (7028): 430–4. doi:10.1136/bmj.312.7028.430. PMC 2350106. PMID 8601117.
  11. ↑ "2018 Adult Schedule by Health Conditions in Easy-to-read Format for Patients". Centers for Disease Control and Prevention. Retrieved 19 June 2018.
  12. ↑ "Asplenia and Adult Vaccination". Centers for Disease Control and Prevention. CDC. Retrieved 8 March 2018.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.