Brain Infection (cont.)
Brain Infection Causes
Causes of bacterial meningitis: Three types of bacteria are the most common causes of meningitis in all age groups except newborns:
- Streptococcus pneumonia (causing pneumococcal meningitis)
- Neisseria meningitidis (causing meningococcal meningitis)
- Haemophilus influenza type b (Hib)
introduction of Hib vaccine as part of routine pediatric immunization has significantly reduced the occurrence of serious Hib disease. Newborns are usually infected with coliform (bacteria in the gut, contracted at birth) such as Escherichia coli or
- How organisms are transmitted: Unlike the flu or the common
cold, which can be transmitted by casual contact or by simply breathing the air in the same room with an infected person, most of the bacteria causing meningitis are not very contagious. It would take the exchange of respiratory and throat secretions, from coughing, sneezing, or kissing, to spread the bacteria. The only exception is meningococcal meningitis. Anyone in the same household, or who had a prolonged contact, or was in direct contact with a person's oral secretions would be considered at increased risk of contracting the infection. People who have been exposed in this manner should receive preventive antibiotics.
- Those most at risk: Anyone can get bacterial meningitis. It most commonly affects infants and small children. Anyone who had close or prolonged contact with a person affected by certain powerful bacteria (such as N. meningitidis or Hib) are also at increased risk. This includes day care workers, military recruits, jail cellmates, and anyone directly exposed to discharges from the mouth or nose of an infected person. The other groups at risk include people with weakened immune systems, diabetics, chronic alcoholics, IV drug abusers, and anyone older than 60 years
- The following are other common brain infections:
- Toxoplasmosis (also known as toxo) is caused by
the parasite Toxoplasma gondii. Infection is acquired, for example, from an infected mother to an unborn baby, by eating unwashed vegetables or undercooked meat, or by direct contact with cat feces (the cat is a host for this organism). The symptoms are similar to a mild form of bacterial meningitis. People at risk are pregnant women and those with weakened immune systems, such as people who are HIV positive. Prognosis is poor for infections transmitted from mother to newborn. More than 50% of affected infants die within a few weeks after birth. The disease also is severe in someone with a weakened immune system, and aggressive treatment with medications is used. Frequently, death results.
- Cerebral cysticercosis is caused by the pork tapeworm. The infestation is acquired when people eat food contaminated by feces or eat the larvae. This disease has recently become relatively common in the
southwestern U.S. Depending on the stage of the disease, it could present as a mild form of meningitis, or more severe form, or even cause sudden death. The most common symptoms are seizures. Few medications can stop the progression of the disease. However, once the cerebral form is acquired, the treatment is usually given to relieve the symptoms.
- Trichinosis is caused by the roundworm Trichinella spiralis. It is acquired by eating larvae in raw or undercooked pork. An infected person may have symptoms similar to encephalitis with confusion and delirium. Coma, seizures, paralysis, and other signs of neurologic loss are found in more severe forms. Most people recover within a few days or weeks without any long-term problems. The treatment is usually for the symptoms.
- Cerebral abscess is often a complication of chronic sinus or middle-ear infections or the distant spread of the infection from somewhere else (such as a lung abscess or pneumonia). It can also be a consequence of head trauma or a neurosurgical procedure. The symptoms depend on the location of the abscess, but almost all people with this condition have a severe headache, fever, or generalized malaise. Treatment includes IV antibiotics and frequently surgical drainage.
Igor Boyarsky, DO, FACEP, FAAEM
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