Spleenectomy (surgical removal of the spleen), or functional asplenia, is a significant risk factor for meningitis. And curiously, the most common bacteria to cause meningitis in these patients is the germ pneumoccus (most commonly associated with bronchitis and pneumonia). Patients with splenic dysfunction lose an important site of both antibody production and immune cell production. They also can no longer filter blood-borne bacteria; hence, a germ that normally causes a respiratory infection can get into the bloodstream and land in the brain.
In the general public, pneumoccus accounts for 70 percent of the cases of meningitis, and is even a more common cause in people with dysfunctional spleens. The most common reason for surgical removal of the spleen is because it ruptured from blunt trauma, such as in sports injuries or motor vehicle accidents. The most common causes for functional asplenia are congenital hyposplenism, sickle cell disease, celiac disease, bone marrow transplant, HIV infection, liver cirrhosis and lymphoma. Luckily there is an excellent way to prevent this meningitis risk and that is to take the pneumovax, also known as PPV-23 (23-valent polysaccharide pneumococcal) vaccine.
One caveat though, is to be sure to measure post-vaccine antibodies. Because the spleen isn’t functional, there is a chance that a single vaccine may not be fully effective. By measuring the antibody levels after vaccination, a determination can be made if a booster is needed.