OTOSCLEROSIS//OTOSPONGIOSIS скачать в хорошем качестве

OTOSCLEROSIS//OTOSPONGIOSIS

Definition & Overview • Otosclerosis is a primary bone disorder of the otic capsule. • Characterized by abnormal bone remodeling, leading to progressive hearing loss. • Common cause of conductive hearing loss in young adults. Epidemiology • Incidence: Affects 0.3-0.4% of the population. • Gender: More common in females (2:1 ratio). • Age: Typically presents in the 20s or 30s. • Family history: Autosomal dominant with incomplete penetrance in 50-60% of cases. Pathophysiology 1. Abnormal Bone Remodeling: • Normally, the otic capsule is stable. • In otosclerosis, excessive bone resorption followed by disorganized new bone formation occurs. 2. Locations: • Most common at the fissula ante fenestram near the stapes footplate. • May extend to the cochlea (cochlear otosclerosis). 3. Types: • Fenestral Otosclerosis: Affects the stapes footplate; leads to conductive hearing loss. • Cochlear Otosclerosis: Invades cochlea; causes sensorineural hearing loss. Clinical Features • Hearing Loss: • Progressive, bilateral, and asymmetrical. • Conductive loss initially, may progress to mixed or sensorineural hearing loss. • Tinnitus: Common due to cochlear involvement. • Paracusis Willisii: Improved hearing in noisy environments. • Vestibular Symptoms: Rare, but dizziness or imbalance may occur. Diagnosis 1. History & Physical Examination: • Progressive hearing loss in young adults. • Family history of otosclerosis. 2. Audiometry: • Conductive hearing loss with Carhart’s notch (dip at 2 kHz in bone conduction). • Mixed hearing loss in advanced cases. 3. Tympanometry: • Normal tympanic membrane with Type A tympanogram. 4. Imaging: • CT scan: Useful for confirming cochlear involvement or differential diagnosis. Management 1. Conservative: • Hearing Aids: Amplify sound to overcome conductive loss. • Medical Therapy: Limited efficacy. • Sodium fluoride or bisphosphonates (for cochlear otosclerosis). 2. Surgical: • Stapedotomy/Stapedectomy: • Microsurgical procedure to replace the stapes with a prosthesis. • Success rate: Improves conductive hearing in most cases. • Cochlear Implant: • For severe cases of cochlear otosclerosis. Complications • Stapedectomy complications: • Sensorineural hearing loss. • Vertigo. • Tinnitus exacerbation. • Untreated cases may progress to profound hearing loss. Prognosis • With surgical intervention, excellent improvement in hearing. • Progression may continue without treatment, leading to irreversible hearing loss.