Meningitis can be either acute or chronic in the onset and progression of the disease.
1) Acute:-cases of acute meningitis are characterized by –fever, stiff neck, headache, nausea, and vomiting, neurologic abnormalities and change in mental status. With acute bacterial meningitis, CSF usually contains large numbers of inflammatory cells (>1000/mm3), primarily polymorphonuclear neutrophils.
The CSF shows a decreased glucose level relative to serum glucose level (the normal ratio of CSF to serum glucose is approximately 0.6), while there is increased protein concentration is shown (normal protein is 15-50mg/dL in adults and as high as 170mg/dL with an average of 90mg/dL in newborns).
The sequelae of acute bacterial meningitis in children are frequent and serious with seizures occurring in 20%-30% of cases in large urban area hospitals. Other neurologic changes are also common. The acute sequelae include; cerebral edema, hydrocephalus, cerebral herniation, and focal neurologic changes.
Permanent deafness can occur in 10% of the children who recover from bacterial meningitis. And a more subtle physiologic and psychological sequelae may follow an episode of acute bacterial meningitis.
Although the morbidity associated with meningitis is still significant, the Haemophilus influenzae type b conjugate vaccine has played a major role in reducing postmeningitis sequelae.
2) Chronic- chronic meningitis often occurs in patients who are immunocompromised, although this is not always the case. Patients experience and insidious onset of disease, with some or all of the following; - fever, headache, stiff neck, nausea, and vomiting, lethargy, confusion, and mental deterioration.
Symptoms may persist for a month or longer before treatment is sought. The CSF usually manifests an abnormal number of cells (usually lymphocystic), elevated protein and some decreased in glucose content. The pathogenesis of chronic meningitis is similar to that of acute disease.
The etiology of acute meningitis is very dependent of the age of the patient, with the majority of cases occurring in children younger than age 5. Neonates have the highest prevalence of meningitis, with a concomitant increased mortality rate as high as 20%.
Organisms causing disease in the newborn are different from those that affect other age groups; many of them are acquired by the newborn during the passage through the birth canal. And are likely to be infected with;-group B Strep., E.Coli, other Gram-Negative Bacilli, and Listeria Monocytogenes, in that order. And occasionally other organisms may be involved. For example Flavobacterium meningosepticum has been associated with nursery outbreaks of meningitis. This is usually a normal inhabitant of water in the environment and is presumably acquired nosocomially.
Important causes of meningitis in the adult, in addition to the meningococci in young adults, includes; - Pneumococci, Listeria Monocytogenes, and less commonly, Staph. Aureus and various Gram-Negative bacilli. With meningitis caused by the latter organisms resulting from the hematogenous seeding from various sources, including urinary tract infections.
Aseptic meningitis:-***** TO BE CONTINUED.******