Chiasmal meningitis

Abstract

Histopathological changes in the optic nerve and chiasm were investigated in 18 cases of meningitis, including 13 cases of purulent meningitis. three cases of cryptococcal meningitis and two cases of tuberculous meningitis. The topographical distributions of the lesions were classified into peripheral, central and transverse types, and we may propose the term peripheral, central and transverse optico-chiasmal neuropathy. The pathological processes on the optic nerve and chiasm in meningitis cases may be divided into inflammatory and vascular disturbance types. The inflammatory type was characterized by the inflammatory invasion into the septal and perivascular tissues, and the parenchyma of the nerve. Consequently, degenerative changes of nerve fibers took place. The vascular disturbance type was characterized by obliterating angiopathies, feeding the optic nerve and chiasm. in the absence — or with only minor infiltrations — of the inflammatory cells in the nerve itself. Subsequently parenchymatous damage occurred.