Bacterial Meningitis

Bacterial Meningitis

The definition of meningitis is any inflammation of the meninges or membranes of the central nervous system. This inflammation can be caused by any number of pathogens such as fungi, viruses, and bacteria. Bacteria is most commonly associated with the disease even though causative viruses can be more prevalent, but never discovered because the mildness of the symptoms. The study of meningitis dates back to the 1960’s when the causative organisms were discovered and treatments were developed. Since then the mortality rate from bacterial meningitis has not changed much despite the introduction of new antibiotics and treatments (Hussein 360).

In the case of bacterial meningitis no one casual organism causes all of the cases, but rather there are many that capable of causing it. Although there are many causal organisms, there are three that are most prevalent in cases diagnosed. Streptococcus pneumoniae is the most common causative agent in the Untied States causing 30-50% of all cases. In recent years many strains of S. pneumoniae have become drug-resistant which makes treatment very difficult and increases the mortality rate. Neisseria meningitidis is the second leading cause of meningitis in the Untied States and first in many parts of Africa. It causes 15-40% of cases depending on location. The third leading cause is from the bacteria Haemophilus influenzae. It causes about 2-7% depending on location. This form is usually found in young children. The occurrence of meningitis caused by H. influenzae has decreased in recent years due to a vaccine given to children in the first few months of life (Philips 110-111).

Transmission of the causative organism occurs by contact of respiratory droplets from an infected person to an uninfected host. It is not as contagious as something like the flu or common cold, but prolonged exposure to an infected individual greatly increases the chance for infection. Most infections occur as a result of a previous, usually viral, infection. This infection lowers the body’s immune response and the causative organism can enter the cerebrospinal fluid through the blood brain barrier and reproduce with immune system directed at the previous infection. The bacteria make their way into the cerebrospinal fluid though a complex system of actions that is aided by the weakened immune system. The immune system inside the cerebrospinal fluid is very weak and depends on the rest of the body to keep out harmful pathogens.