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Meningitis is inflammation of the membranes ( meninges) covering the brain and the spinal cord. Although the most common causes are infection (either bacterial or viral), chemical agents and even tumor cells may cause meningitis. Encephalitis and brain abscess can complicate infective meningitis.1 Causative organisms
Major bacteria that cause meningitis are Streptococcus pneumoniae, Haemophilus influenzae, staphylococcus and meningococcus.
Meningitis caused by Haemophilus influenzae is known to occur in outbreaks, examples include outbreaks in dorms and military outbreaks.
Community acquired cases of meningitis are usually caused by Streptococcus pneumoniae, seen in elderly patients. Listeria monocytogenes and Neisseria meningitis are also other causes of community acquired meningitis. On the other hand, viruses are the most common cause of aseptic meningitis.
2 Incidence
20,000 to 25,000 cases of bacterial meningitis are seen in the United States every year. Mostly adults are infected, where it can be community acquired or nosocomial. Vaccination against Haemophilus influenzae has reduced the incidence in children.
3 Symptoms
The classical symptoms of meningitis are headache, neck stiffness and photophobia (the trio are called "meningism"). An altered level of consciousness or other neurological deficits may be present depending on the severity of the disease. A lumbar punctureIn medicine, a lumbar puncture (colloquially known as a spinal tap is a diagnostic procedure that is done to collect a sample of cerebrospinal fluid (CSF) for biochemical, microbiological and cytological analysis. Indications The most common indication fo to obtain cerebrospinal fluidCerebrospinal fluid CSF in short, is the clear fluid that occupies the subarachnoid space (the space between the skull and cortex of the brain). It acts as a "cushion" or buffer for the cortex. Also, CSF occupies the ventricular system of the brain and th (CSF) is usually indicated to determine the cause and direct appropriate treatment.
4 Treatment
Meningitis is a medical emergency, being a condition with a high mortality rate if untreated. The cause is most commonly a bacterial infection sensitive to antibioticAn antibiotic is a drug that kills or slows the growth of bacteria. Antibiotics are one class of "antimicrobials", a larger group which also includes anti-viral, anti-fungal, and anti-parasitic drugs. They are relatively harmless to the host, and therefors. Patients with suspected meningitis should optimally initially have a CT scanComputed axial tomography (CAT computer-assisted tomography computed tomography CT or body section roentgenography is the process of using digital processing to generate a three-dimensional image of the internals of an object from a large series of two-di to help determine if there is a raised intracranial pressure that might cause a serious or fatal brain herniation during lumbar puncture. If there are no signs of elevated central nervous system pressure demonstrated on the CT scan, a lumbar punctureIn medicine, a lumbar puncture (colloquially known as a spinal tap is a diagnostic procedure that is done to collect a sample of cerebrospinal fluid (CSF) for biochemical, microbiological and cytological analysis. Indications The most common indication fo procedure is performed to obtain cerebrospinal fluid for microscopic examination, chemical analysis, and bacterial cultures. Broad spectrum antibiotics should be urgently started before the culture results are available. If lumbar puncture can not be performed because of raised intracranial pressure (likely due to edema or concomitant brain abscess), a broad spectrum intravenous antibiotic should be started immediately (this is often a third generation cephalosporinThe cephalosporins are a class of ss-lactam antibiotics. Together with cephamycins they belong to a sub-group called cephems. History Cephalosporin was first isolated from cultures of Cephalosporium acremonium from a sewer in Sardinia in 1948 by an italia). When cerebrospinal fluid gram stain, or blood or CSF culture and sensitivity results, are available, the empiric treatment can be refined by switching to more specific antibiotics. In children (but not in adults) the administration of steroids helps reduce the incidence of deafness following meningitis.
Infection of the meninges usually originates through spread from infection of the neighbouring structures (which include the sinuses and mastoid cells of ear). These should be investigated when diagnosis of meningitis is confirmed or suspected.
