It is an infection of the layers that surround and protect the brain and spinal cord, called the meninges.
The most common bacteria involved are: Meningococcus, Pneumococcus, Group B Streptococcus and Haemophilus influenzae. In patients between 50 and 60 years of age with cellular immunodeficiency, the most frequent bacterium is Listeria monocytogenes. Risk factors or situations that favour the appearance of meningitis are sinusitis, otitis media, diabetes, alcoholism, absence of spleen, and craniocerebral trauma with cerebrospinal fluid leaking from the nose (rhinorrhoea).
It typically manifests with fever, headache, neck muscle stiffness and altered mental status. Other associated symptoms are nausea and vomiting, drowsiness, confusion, convulsions, irritability, photophobia, etc. When the cause is meningococcus, skin lesions may appear.
Diagnosis is based on clinical history and physical examination, and is confirmed by analysis of cerebrospinal fluid.
Treatment is early antibiotic treatment, combined with corticosteroids if pneumococcal or H. influenzae meningitis is suspected. Antipyretics will be added to control fever, anticonvulsants if seizures occur, and serum therapy to maintain vital signs.
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