Meningitis is an infectious disease that is a diffuse inflammatory lesion caused by pathogenic microorganisms invading the soft meninges and arachnoid membranes of the central nervous system. The causative organisms include viruses, bacteria, fungi, etc. Some patients carrying the pathogens may be infectious, and children and the elderly or patients with low resistance to infection are more likely to be infected. Meningitis caused by various viral infections is called viral meningitis, which is mostly caused by enteroviruses and is mainly transmitted by the fecal-oral route, and a few by respiratory secretions. The virus replicates after invading the body, then enters the bloodstream to produce viremia, and enters the cerebrospinal fluid through the choroid plexus to invade the meninges, causing inflammatory lesions in the meninges. Inflammatory diseases caused by various bacterial invasion of the meninges are bacterial meningitis, with septic meningitis and tuberculous meningitis being common. The routes of infection in septic meningitis include hematogenous dissemination, direct diffusion, and transcerebrospinal pathways. Epidemic meningitis due to S. meningitidis occurs in children and is contagious, mainly through the respiratory route; pneumococcal meningitis occurs in the elderly; tuberculous meningitis is often secondary to cornual tuberculosis or tuberculosis of other organs in the body and occurs in children and young adults and is not very contagious. The most common fungal infection is cryptococcal meningitis, which is caused by a new type of cryptococcal infection of the meninges. Cryptococcus is a conditionally pathogenic bacterium that easily multiplies in dry alkaline and nitrogen-rich soil, and the infection rate is higher in pigeon breeders than in the general population, as well as in immunocompromised patients. The early clinical manifestations of meningitis vary due to the different causative organisms, and in severe cases can lead to death or serious sequelae, but most are curable if treated early.