Tuberculous meningitis-induced unilateral sensorineural hearing loss: a temporal bone study.
The relationship between meningitis and sensorineural hearing loss (SNHL) has long been studied. Many histopathological studies of animal models and human temporal bones with respect to bacterial meningitis have been carried out. However, the relationship between SNHL and tuberculous meningitis was seldom addressed and the pathophysiology remains unclear. We carried out temporal bone studies on material from a 22-year-old patient who developed a right unilateral SNHL before dying from tuberculous meningitis. The histopathological findings for the right temporal bone were as follows: (1) inflammation mainly appeared in the internal auditory canal, modiolus and Rosenthal's canal and extended to the osseous spiral ligament, whereas the perilymphatic spaces were less involved; (2) the organ of Corti, cochlear nerve fibres and spiral ganglion cells were severely degenerated, particularly in the basal and middle turns; (3) the contralateral side (for which the patient had no complaints) showed an inner space free from inflammation, but some granulomatous formations were observed in the middle ear cavity. We conclude that the modiolus and cochlear aqueduct are the main routes for the spread of infection from the meninges to the inner ear. The progression of hearing loss resembles that of bacterial meningitis and shares attributes of retrocochlear SNHL.
Kuan
Chen-Chieh
CC
Department of Otolaryngology and Head and Neck Surgery, Faculty of Medicine, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. volvo9837@yahoo.com
Kaga
Kimitaka
K
Tsuzuku
Toshihiro
T
D000328:Adult; D001921:Brain / Q000473:pathology; D003056:Cochlear Nerve / Q000473:pathology; D003937:Diagnosis, Differential; D007758:Ear, Inner / Q000473:pathology*; D005158:Facial Paralysis / Q000473:pathology; D017809:Fatal Outcome; D006198:Hair Cells, Auditory / Q000473:pathology; D006319:Hearing Loss, Sensorineural / Q000473:pathology*; D046088:Hearing Loss, Unilateral / Q000473:pathology*; D006801:Humans; D008297:Male; D009925:Organ of Corti / Q000473:pathology; D010034:Otitis Media with Effusion / Q000473:pathology*; D013701:Temporal Bone / Q000473:pathology*; D014390:Tuberculosis, Meningeal / Q000473:pathology*