Introduction Meningitis infects the meninges, the delicate membranes that house the spinal cord and the brain. It is a rare infection that can affect adults and children alike. The disease manifests in several types such as through viral, bacterial and fungal varieties. Bacterial meningitis is the most dangerous and infectious variety. It is a life threatening disease. It infects people in physical contact. Incidentally, viral meningitis is not as severe as most of the patients that develop the disease recover on their own without seeking treatment (Wang et al., 2014). Fungal meningitis is the rarest form. It occurs in people whose immune system has been compromised.

Etiology

Bacterial meningitis is caused by bacteria that enters the body and relocates to the brain and spinal cord or when bacteria invade the meninges. The point of entry can be a skull fracture, ear or sinus infection, of surgery. Bacteria that cause bacterial meningitis include Streptococcus pneumonia, (the most common cause of bacterial meningitis) Neisseria meningitides, Haemophilus infleunzae, and Listeria monocytogenes (people who have weakened immune systems are most susceptible). Bacterial meningitis is commonly caused by S pneumonia in America and other countries across the globe.The common serotypes that lead to bacterial meningitis include 4, 6B, 9V, 14, 19, 18C, and 23. Pneumococcal strain 19A is the most notable serotype that causes the disease and can attack both children and adults (Kaplan et al., 2014; Wang et al., 2014).

Viral meningitis is caused by enteroviruses which are common in late summer and early fall. Viral meningitis is however mild and clears without medication. Chronic meningitis on the other hand is caused by organisms that are slow-growing e.g. Mycobacterium tuberculosis and fungi. Fungal meningitis is uncommon with only Cryptococcal meningitis being the common form and it affects persons with immune deficiencies...

AIDs. Other causes of meningitis are noninfectious and include drug allergies, chemical reactions, inflammatory diseases, and some types of cancer.
Pathogenesis

The entry point for pathogens that cause meningitis is the nasopharynx or ears into the bloodstream. They pass through the endothelial cells to enter the subarachnoid space, and then penetrate the porous capillaries of choroid plexus. They may be carried by granulocytes too. Provision of sufficient nutrients for the thriving of bacteria is one of the reasons why the Cerebrospinal fluid (CSF) is an ideal medium for infection. It also houses a couple of phagocytic cells. The antibodies are also low (McGill et al., 2016). At first there is uninhibited multiplication of bacteria. At this point the bacteria can be seen and identified through cultures, smears or through Enzyme-linked immunosorbent assay detection of antigens prior to inflammation.

Bacteria carry the potential to destroy the blood capillaries and the brain directly. The toxins generated by bacteria cause neuronal apoptosis. The endotoxin produced by bacteria triggers clotting which in turn leads to disseminated intravascular coagulation. This state leads to more severe injury because of the inflammatory reaction to bacteria. The innate immune system of the brain found in the choroid.

Actually, if neutrophytes increase in number, they can damage brain nerves, vessels and tissue. Cerebral infarcts are caused by Vasculitis and clotting. This brain damage during attack by meningitis is as a result of bacterial action in part and also the reaction to bacteria by the immune response system. The brain is sufficiently wired to deal with inflammation. However, in some situations, the unbalanced defense responses can be injurious. Increased intracranial pressure from cerebral edema is the most severe and dangerous complication of bacterial meningitis. The edema could be vasogenic as a…