Health Dictionary
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Overwhelming post-splenectomy infection
Introduction
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Synonyms and keywords: OPSI
Overview
Overview
Overwhelming post-splenectomy infection is a rapidly fatal septicemia infection due to the absence of spleen protection against certain bacteria (asplenia). Patients with absent (eg splenectomy) or non-functional spleens can die of these uncommon infections in a few hours.
Epidemiology and Demographics
The risk of contracting an OPSI for such patients is 0.23-0.42% per year, with a lifetime risk of 5%, and an associated mortality of 38-69%.[1]
Treatment
Primary Prevention
Prevention with vaccinations and antibiotics can largely prevent OPSI.[2][3]
References
- ↑ Davidson R, Wall R (2001). “Prevention and management of infections in patients without a spleen”. Clin Microbiol Infect. 7 (12): 657–60. PMID 11843905.
- ↑ “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. PMID 8601117.
- ↑ J M Davies; 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.
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Pathophysiology
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Pathophysiology
The spleen contains many macrophages (part of the reticuloendothelial system), immune cells which phagocytose (eat) and destroy bacteria. In particular, these macrophages are activated when bacteria are bound by IgG antibodies (IgG1 or IgG3) or complement component C3b. These types of antibodies and complement are immune substances called opsonizers, molecules which bind to the surface of bacteria to make them easier for macrophages to phagocytose and destroy the bacteria.
When the spleen is gone, IgG and complement component C3b are still bound to bacteria, but they cannot be removed from the blood circulation because the spleen, which contained the macrophages, is gone. The bacteria therefore are free to cause infection.
Patients without spleen often need immunizations against pathogens that normally require opsonization and phagocytosis by macrophages in the spleen. These include common human pathogens with capsules (Streptococcus pneumoniae, Salmonella typhi, Neisseria meningitidis, E. Coli, Hemophilus influenzae, Streptococcus Agalactiae, Klebsiella pneumoniae). Capsules (made of polysaccharides) are an evolutionary development by bacteria to evade phagocytosis by macrophages alone, since only proteins are directly recognized by macrophages in phagocytosis. Humoral immunity in the form of IgG and complement proteins is the answer of the human immune system to allow these pathogens marked for destruction.
References
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Causes
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Causes
Common Causes
- E. coli
- Hemophilus influenzae
- Klebsiella pneumoniae
- Neisseria meningitidis
- Salmonella typhi
- Streptococcus agalactiae
- Streptococcus pneumoniae
References
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Differentiating Overwhelming Post-splenectomy Infection from other Diseases
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References
Epidemiology and Demographics
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Overview
The risk of contracting an OPSI for such patients is 0.23-0.42% per year, with a lifetime risk of 5%, and an associated mortality of 38-69%.[1]
References
- ↑ Davidson R, Wall R (2001). “Prevention and management of infections in patients without a spleen”. Clin Microbiol Infect. 7 (12): 657–60. PMID 11843905.
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Risk Factors
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References
Natural History, Complications and Prognosis
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References
Diagnosis
Diagnosis
History and Symptoms | Physical Examination | Laboratory Findings | Chest X Ray | Ultrasound | Other Imaging Findings | Other Diagnostic Studies
Treatment
Treatment
Medical Therapy | Primary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]