Hearing Loss - Differential Diagnosis Framework Hearing Loss Types: • Conductive • Sensorineural • Mixed Presbycusis is the most common type in adults (bilateral age related hearing loss) History: • Duration of hearing loss? • Bilateral? • Fluctuating? • Progressive? The evaluation should also include a: • Neurologic review • History of: • Diabetes mellitus • Stroke • Vasculitis • Head or ear trauma • Use of ototoxic medications • Family history of ear conditions and hearing loss Exam: • Hearing tests such as the whispered voice test or audiometry • Patients should then undergo examination for: • Cerumen impaction • Exostoses • Other abnormalities of the external canal and tympanic membrane • Neurologic examination: ○ Cranial nerves - tumors of the auditory nerve (acoustic neuroma) and stroke may affect cranial nerves V and VII. • Head and neck masses and lymphadenitis? Infection or cancer Tuning Fork Tests (512 Hz) Weber Test: • Lateralization to good ear indicates sensorineural hearing loss • Lateralization to bad ear indicates conductive hearing loss Rinne Test: • Normal: Air > bone • Conductive hearing loss: Bone > Air conduction Conductive Hearing Loss Conductive problems involve the tympanic membrane and middle ear, and interfere with transmitting sound and converting it to mechanical vibrations. • Outer Ear: ○ Obstruction of external canal by cerumen ○ Obstruction of external canal by exostoses (surfer’s ear) ○ Obstruction of external canal by foreign body ○ Otitis externa • Middle Ear: ○ Cholesteatoma ○ Ossicular chain disruption ○ Otitis media ○ Otosclerosis Tympanic Membrane: • Perforation, tympanosclerosis Sensorineural Hearing Loss Sensorineural problems affect the conversion of mechanical sound to neuroelectric signals in the inner ear or auditory nerve (CN 8). • Unilateral: ○ Internal auditory artery infarct (Labyrinthine artery) – Sudden Onset ○ Meniere disease ○ Vestibular Schwannoma/Acoustic neuroma ○ Viral ○ Idiopathic SNH (80% to 90% of cases cause unknown) • Bilateral: ○ Presbycusis - is the most common type in adults ○ Ototoxic medications (Aminoglycosides, ASA, etc.) ○ Meningitis complications ○ Neurofibromatosis type II ○ Susac’s syndrome ○ Superficial Siderosis ○ Mitochondrial disorders ○ Noise trauma ○ MS, CVA • Infectious Conditions: ○ Labyrinthitis ○ Epstein-Barr virus ○ Group A Streptococcus ○ Herpes simplex virus ○ Herpes zoster virus ○ HIV ○ Lyme disease ○ Meningitis ○ Syphilis Cerebellopontine angle tumor/neoplasm • Trauma: ○ Barotrauma, ear trauma, or head trauma ○ Noise exposure #Hearing #Loss #Differential #Diagnosis #otology #otolaryngology
