Meningit'is (Gr. mēninx, 'a membrane') is the term employed in medicine to designate inflammation of the membranes investing the brain and spinal cord, of which in this relation the innermost—the pia-mater—is the most important. Far the most frequent form of meningitis in Britain is the tubercular, already described under Hydrocephalus (q.v.); and, as the main symptoms of other forms are similar, it is unnecessary to repeat them here.
Epidemie cerebro-spinal meningitis, or Cerebro-spinal fever.—Outbreaks have occurred from time to time during the 19th century in the northern hemisphere, less frequently in the British Islands than in most of the other countries where qualified observers are found, of an epidemic disease affecting chiefly the membranes of the brain and cord. It usually begins suddenly with fever and violent headache; vomiting, giddiness, stupor, delirium, and other nervous symptoms succeed, the most distinctive of which is a peculiar rigidity of the muscles of the neck and back. The disease is extremely variable in severity; sometimes it is fatal in less than twenty-four hours; sometimes so slight as only to confine the patient to bed for a few days. The majority lie between these extremes, improvement in favourable cases beginning after a week or two. Convalescence is often very slow. It occurs chiefly in children and young adults. It is not clearly distinguishable from other forms of meningitis except by its mode of occurrence, generally in somewhat localised and limited outbreaks. If contagious, it is only feebly so. Treatment must be conducted on general principles, as no specific is yet known.
Simple meningitis (i.e. not traceable to tubercle or to the epidemic form) is most often caused by injury, but may result from disease of the skull, pyæmia, and other diseases, and has even been caused by excessive exposure of the head to the sun. It usually begins, unlike the tubercular form, quite suddenly; and it too is an extremely fatal disease. But the outlook is not quite so hopeless in simple meningitis; and even cases which appear desperate do sometimes recover. The essentials of treatment are rest and quiet in a darkened room, and little food of the lightest kind. Ice to the head, blistering, blood-letting, local or general, and free purgation sometimes seem beneficial.