Meningitis is a clinical syndrome characterized by inflammation of the meninges(covering of brain and spinal cord). The inflammation may be caused by infection with viruses, bacteria, or other microorganisms.
The classic triad of bacterial meningitis consists of the following:
Other symptoms can include nausea, vomiting, photophobia, sleepiness, confusion, irritability, delirium, and coma. Patients with viral meningitis may have a history of preceding systemic symptoms (eg, myalgias, fatigue, or anorexia). Meningitis caused by meningococcal bacteria may be accompanied by a characteristic rash.
Newborns and infants may not have the classic signs and symptoms of headache and stiff neck. Instead, signs of meningitis in this age group may include:
Excessive sleepiness or irritability
Inactivity or sluggishness
A bulge in the soft spot on top of a baby's head (fontanel)
Stiffness in a baby's body and neck
Meningitis is generally caused by infection of viruses, bacteria, fungi, parasites, and certain organisms. Anatomical defects or weak immune systems may be linked to recurrent bacterial meningitis. In the majority of cases the cause is a virus. However, some non-infectious causes of meningitis also exist.
Lumbar puncture and CSF fluid analysis
Extremes of age (< 5 or >60 years)
Diabetes mellitus, renal or adrenal insufficiency, hypoparathyroidism, or cystic fibrosis
HIV infection, which predisposes to bacterial meningitis caused by encapsulated organisms, primarily Streptococcus pneumoniae, and opportunistic pathogens
Crowding (such as that experienced by military recruits and college dorm residents), which increases the risk of outbreaks of meningococcal meningitis
Splenectomy and sickle cell disease, which increase the risk of meningitis secondary to encapsulated organisms
Alcoholism and cirrhosis
Recent exposure to others with meningitis, with or without prophylaxis
Contiguous infection (eg, sinusitis)
Dural defect (eg, traumatic, surgical, or congenital)
Intravenous (IV) drug abuse
Malignancy (increased risk of Listeria infection)
Disseminated intravascular coagulation
Waterhouse-Friderichsen syndrome in meningococcal meningitis
Rise in ICP and brain herniation
Focal neurological deficits
Immediate use of broad spectrum antibiotics and supportive management.