Study of pattern of hearing loss in CSOM (chronic suppurative OTITIS media)

Introduction: Chronic suppurative otitis media is one of the most common conditions encountered by Otologists in daily practice. Conventionally hearing loss in CSOM is conductive in nature, but it has been observed that some patient displayed an additional sensorineural component to their conductive hearing loss (mixed hearing loss). Material and Methods: A prospective cohort observational study on 100 Cases in two groups of 50 each who had safe CSOM and 50 unsafe CSOM conducted over a period of July 2011 to September 2013 at the Department of Otorhinolaryngology, Padmashree Dr. D. Y. Patil Medical College, Hospital and Research Centre (DPU), Pimpri, Pune. Detailed history, complete ENT examination was done. They were then subjected to Puretone audiometry; air and bone conduction thresholds were tested and plotted on the audiogram. Univariate and multivariate logistic regression (odds ratio) analyses were used. Results: Incidence of hearing loss is 72%for conductive type and 28% is of mixed type, in which 72% are of safe conductive, 18% safe mixed type and 64% are of unsafe conductive, 36% are in unsafe mixed type. Incidence of SNHL increases as age increases being maximum in age group of 41-50 years i.e. 37.50% and minimum in 11-20 years i.e. 5.71%. 14% cases of unsafe chronic suppurative otitis media were found to be associated with labyrinthine fistula. This proved to be the commonest cause of sensorineural component in unsafe chronic suppurative otitis media followed by granulation over oval window (8%) and cholesteatoma extending to round window in 4 % of cases. Conclusion: In the present study incidence of sensorineural hearing loss increased with advancing age, showing that age is a risk factor for sensorineural component of hearing loss in CSOM though conductive hearing loss is more common. CSOM is associated with mixed hearing loss mainly >35dB, higher frequencies were involved.