Meningitis can be subdivided based on time course of onset and duration, cerebrospinal fluid (CSF) profile, and underlying origins into acute aseptic and septic meningitis, recurrent meningitis, and chronic meningitis. These are distinct syndromes that require different management strategies. Most cases of meningitis are caused by infection. The causal agent is generally predictable based on the type of meningitis, host factors, and clues from the history and examination. CSF examination remains the critical diagnostic test.