1. Meningitis is an inflammation of the protective membranes (meninges) surrounding the brain and spinal cord. 2. It is usually caused by viral or bacterial infection, with common bacteria being Hemophilus influenzae, Streptococcus pneumoniae, and Neisseria meningitidis. 3. Symptoms include high fever, nausea, vomiting, irritability, photophobia, and headache. Increased intracranial pressure can also occur.