SUMMARY
1. The spleen is the largest lymphatic organ in the body. There are three main functions of the spleen:
- Phagocytosis and clearance of microorganisms, particularly bacteria that is non-opsonized with complement proteins or antibodies.
- The spleen serves as a site for interaction of T cells with antigen presenting cells and B cells as well as a site for B cell activation and antibody production.
- Removal of particulate matter from the blood including spherocytes, aging red blood cells and antibody coated blood cells.
2. Asplenia may occur due to a congenital absence of the spleen, removal of the spleen (due to trauma or for treatment of conditions such as spherocytosis, thalassemia or refractory ITP) or functional asplenia (most commonly from sickle cell disease).
3. Asplenia is associated with an increased risk of disseminated infection with encapsulated bacteria such as S. pneumonia, H. influenza, and N. meningitidis.
4. Bacterial polysaccharide antibody response is suboptimal in children until the age of 2 to 5 years. Thus, infants and toddlers with asplenia are at greatest risk for invasive bacterial infections.
5. Laboratory abnormalities include reduced IgM antibody responses. However, IgG antibody responses appear to be intact for patients. Quantitative or functional T cell impairment is not present.
6. If possible, pneumococcal, meningococcal and H. influenzae vaccines should be administered two weeks prior to elective splenectomy for patients. Determination of appropriate vaccine responses and periodic re-evaluation of antibody titers is recommended.
7. Antibiotic prophylaxis should be administered for asplenic patients (amoxicillin 20mg/kg/day divided twice daily). 8. Febrile episodes require blood cultures and empiric treatment with broad spectrum antibiotics such as amoxicillin-clavulanate.
OVERVIEW
The spleen is the largest lymphatic organ in the body. There are three main functions of the spleen:
- Phagocytosis and clearance of microorganisms, particularly bacteria that is non-opsonized with complement proteins or antibodies. As a result, the spleen plays a key role during primary infections and early secondary infection when antibody levels are low.
- The spleen serves as a site for interaction of T cells with antigen presenting cells and B cells as well as a site for B cell activation and antibody
production.
- Removal of particulate matter from the blood including spherocytes, aging red blood cells and antibody coated blood cells.
Asplenia may occur due to a congenital absence of the spleen, removal of the spleen (due to trauma or for treatment of conditions such as spherocytosis, thalassemia or refractory ITP) or functional asplenia (most commonly from sickle cell disease).
Asplenia is associated with an increased risk of disseminated infection with encapsulated bacteria such as S. pneumonia, H. influenza, and N. meningitidis. Phagocytosis of these pathogens is difficult unless they are appropriately opsonized with anitibodies or complement proteins.
Bacterial polysaccharide antibody response is suboptimal in children until the age of 2 to 5 years. Thus, infants and toddlers with asplenia are at greatest risk for invasive bacterial infections.
Laboratory abnormalities include reduced IgM antibody responses. However, IgG antibody responses appear to be intact for patients. Quantitative or functional T cell impairment is not present.
MANAGEMENT
If possible, pneumococcal, meningococcal and H. influenzae vaccines should be administered two weeks prior to elective splenectomy for patients. Patients older than 2 years of age can receive the pneumococcal polysaccharide vaccine. Patients younger than 2 years of age should receive the pneumococcal conjugate vaccine. Determination of appropriate vaccine responses and periodic re-evaluation of antibody titers is recommended.
Antibiotic prophylaxis should be administered for asplenic patients (amoxicillin 20mg/kg/day divided twice daily).
Febrile episodes require blood cultures and empiric treatment with broad spectrum antibiotics such as amoxicillin-clavulanate.
RESOURCES
Literature Resources
1. Ram 2010
Infections in patients who have undergone splenectomy
Memory B cells and pneumococcal antibody after splenectomy