* * *
Inflammation of the membranes of the brain or spinal cord. SEE ALSO: arachnoiditis, leptomeningitis. SYN: cerebrospinal m.. [mening- + G. itis, inflammation]
- basilar m. m. at the base of the brain, due usually to tuberculosis, syphilis, or any low-grade chronic granulomatous process; may result in an internal hydrocephalus.
- cerebrospinal m. SYN: m..
- eosinophilic m. SYN: angiostrongylosis.
- epidemic cerebrospinal m. SYN: meningococcal m..
- epidural m. SYN: pachymeningitis externa.
- external m. SYN: pachymeningitis externa.
- internal m. SYN: pachymeningitis interna.
- listeria m. SYN: listeriosis.
- meningococcal m. an acute infectious disease of children and young adults, caused by Neisseria meningitidis characterized by fever, headache, photophobia, vomiting, nuchal rigidity, seizures, coma, and a purpuric eruption; even in the absence of m., meningococcemia can induce toxic phenomena such as vasculitis, disseminated intravascular coagulation, shock, and Waterhouse-Friderichsen syndrome due to adrenal hemorrhage; late complications include paralysis, mental retardation, and gangrene of extremities. SYN: cerebrospinal fever, epidemic cerebrospinal m..Approximately 2500 cases of invasive meningococcal disease occur annually in the U.S., with a case fatality rate of 10–15%. The incidence of endemic meningococcal disease peaks between late winter and early spring. Attack rates and case fatality rates are highest among children aged 6–12 months. Household exposure to tobacco smoke is a risk factor for meningococcal disease in children. Organisms are spread from person to person by direct contact and in saliva and respiratory secretions. The epidemiology of meningococcal disease is poorly understood. The nasopharyngeal carriage rate in the general population is 5–10%. This asymptomatic carrier state can persist for months or years and may confer protection against invasive disease. During epidemics of meningococcal m., the carrier rate can approach 95%, yet fewer than 1% may develop the disease. Diagnosis is established by the finding of meningococci in cerebrospinal fluid or blood. Because meningococcemia can progress fulminantly to an irreversible stage, intravenous penicillin G, ampicillin, or chloramphenicol is begun as soon as the diagnosis is suspected, usually before laboratory confirmation. Intensive support of vital functions is crucial during the acute phase. Close contacts of known cases are treated prophylactically with rifampin or ciprofloxacin; mass prophylaxis may be appropriate in a confirmed institutional outbreak. A quadrivalent vaccine has been effective in preventing meningococcal disease due to serogroups A, C, W-135, and Y. Shortcomings of the vaccine are that it does not protect against serogroup B, which causes 30–40% of meningococcal disease in the U.S.; does not interrupt the carrier state; does not induce immunity quickly enough to protect a person already infected; and protects for only 4–5 years. Routine immunization is recommended only for military recruits, travelers to endemic areas, and others known to be at long-term high risk. A major objection to infant vaccination has been the poor induction of immunity in this age group to serogroup C, which causes 45% of m. in the U.S. Use of a meningococcal C vaccine conjugated to protein has yielded high initial titers of anticapsular and bactericidal antibody in infants and toddlers, as well as more prolonged protection and better response to booster doses.
- Mollaret m. a recurrent aseptic m.; febrile illness accompanied by headaches, malaise, meningeal signs, and cerebrospinal fluid monocytes.
- neoplastic m. infiltration of subarachnoid space by neoplastic cells, typically medulloblastoma or metastatic carcinoma. SYN: neoplastic arachnoiditis.
- tuberculous m. inflammation of the cerebral leptomeninges marked by the presence of granulomatous inflammation; it is usually confined to the base of the brain (basilar m., internal hydrocephalus) and is accompanied in children by an accumulation of spinal fluid in the ventricles (acute hydrocephalus). SYN: cerebral tuberculosis (1).
* * *
1) inflammation of the meninges and esp. of the pia mater and the arachnoid
2) a disease that may be either a mild illness caused by any of numerous viruses (as various coxsackieviruses) or a more severe usu. life-threatening illness caused by a bacterium (esp. the meningococcus or the serotype designated B of Hemophilus influenzae), that may be associated with fever, headache, vomiting, malaise, and stiff neck, and that if untreated in bacterial forms may progress to confusion, stupor, convulsions, coma, and death
* * *
n.
an inflammation of the meninges due to infection by viruses or bacteria or fungi. Meningitis causes an intense headache, fever, loss of appetite, intolerance to light and sound, rigidity of muscles, especially those in the neck (see also Kernig's sign), and in severe cases convulsions, vomiting, and delirium leading to death. The most important causes of bacterial meningitis are Haemophilus (especially in young children); two strains of Neisseria meningitidis (the meningococcus), B and C; and Streptococcus pneumoniae (pneumococcal meningitis). Immunization against Haemophilus meningitis and meningitis C is now routine (see Hib vaccine, meningitis C vaccine); there is at present no vaccine available for meningitis B. In meningococcal meningitis (meningitis B and C, previously known as cerebrospinal fever and spotted fever) the symptoms appear suddenly and the bacteria can cause widespread meningococcal infection culminating in meningococcal septicaemia, with its characteristic purple haemorrhagic rash anywhere on the body. The rash does not disappear on pressure (if a glass is pressed on the rash, it is still visible through the glass). Unless quickly diagnosed and treated, death can occur within a few hours.
Bacterial meningitis is treated with large doses of antibiotics administered as soon as possible after diagnosis. With the exception of herpes simplex encephalitis (which is treated with aciclovir), viral meningitis does not respond to drugs but normally has a relatively benign prognosis. See also leptomeningitis, pachymeningitis.
* * *
men·in·gi·tis (men″in-jiґtis) pl. meningiґtides [mening- + -itis] inflammation of the meninges, usually by either a bacterium (bacterial m.) or a virus (viral m.). meningitic adjMedical dictionary. 2011.