I Conductive hearing loss A Congenital or neonatal Malformation of the auricle or external ear canal Atresia of the ossicle chain B Acquired Middle ear effusion (acute or chronic) Impacted cerumen Foreign body of external ear canal Otitis externa Ossicle dysfunction (fixation) Cholesteatoma Acute trauma a Hemotympanum b Rupture of the tympanic membrane c Disruption of the ossicles II Sensorineural hearing loss A Congenital or neonatal Anatomic abnormalities a Aplasia of the inner ear (Michel aplasia) b Abnormal cochlear development Syndromes (more than 70 described with hearing loss) a Waardenburg syndrome b Jervell and Lange-Nielsen syndrome (prolonged Q-T syndrome) c Usher syndrome d Alport syndrome Chromosomal abnormalities a Trisomy 13–15 b Trisomy 18 c Trisomy 21 Infections a TORCH b Congenital syphilis Metabolic a Hypothyroidism