Ambulatory Care Topics: Hearing Loss

1. Ambulatory Care Topics: Hearing Loss Gustavo R. Heudebert, MD Division of General Internal Medicine

2. Road Map • Physiology of hearing • Topography of hearing loss • Differential Diagnosis • Clues from history / physical examination • Evaluation

3. Case 34 yo male comes to the walk-in clinic with a 36 hour history of hearing loss. Onset has been sudden, the the hearing loss is associated with mild bilateral ear pain but no drainage. There is no dizziness or tinnitus. Patient is healthy and takes no medications. Family history is non contributory. There is no exposure to alcohol, tobacco, or illicit drugs. He works at a hospital. Physical examination is unrevealing except for the following:

5. Physiology of Hearing • Outer / middle ear • Amplifier of sound • Internal ear • Transducer • Liquid media • Neural pathways

7. Topography • Conductive • Outer / middle ear • Sensorineural • Inner ear and neural pathways • Mixed • Combination of middle and inner ear

8. History • Acute (< 72 hours) versus chronic • Unilateral versus bilateral • Sudden versus insidious onset • Rate of progression • Associated symptoms • Tinnitus, vertigo, otorrhea • Exposures: toxins, environment

9. Physical Examination • Confirming hearing loss • Whisper test • Hum test • Rinne and Weber test • Otoscopy with insufflation

11. Rinne test AC > BC If BC > AC Conductive disorder on affected ear Weber test Normal test No lateralization Lateralizes to “good ear” SNHL on bad ear Lateralizes to “bad ear” Conductive disorder of that ear Interpretation

12. Interpretation

13. Laboratory Testing • Audiologic assessment • Pure tone audiometry • Speech audiometry • Tympanometry • Evoked responses • Imaging (selective)

15. Hearing Loss Acute History Chronic Normal Exam Audiologic Evaluation Conductive SNHL Abnormal SOM / AOM Perforation Otitis

16. Outer / external Cerumen Tumors Osteoma SCCA External otitis Middle Otitis media Otosclerosis Choleastatoma TM pathology Perforation Hemorrhage Conductive Hearing Loss

17. Inner Ear Hereditary Presbycusis Meniere’s Drugs Environmental Sound Barotrauma Neural Pathways Tumors Schwannoma Demyelinating disorders Vascular CVA Sensorineural Hearing Loss

18. Sudden SNHL • Less than 72 hours duration • Uncommon: 5 to 20 / 100,000 • Age 43 to 53 years; equal gender • Variable recovery • Old age / vestibular symptoms • Vestibular symptoms: 305 to 60%

19. Sudden SNHL • Etiology • 1% “retrocochlear”: tumors, MS, CVA • 15% other: CTD, Lyme, syphilis • Remainder: idiopathic • Rare: decrease ICP (post tap), paraneoplastic, encephalitis, dural process. • Delay in diagnosis common: patient and doctors

20. Sudden SNHL • Quick evaluation • Alternate ears during phone conversation • Hum test • If suspicious for SNHL • Audiometry: if confirmatory then MRI • Therapy: controversial • Prednisone 1 mg/kg then over 10 days • Intratympanic steroids

22. Summary • Common problem • Acuteness, associated symptoms, age, physical examination • Occasional needs further assessment • SNHL: acute or chronic • Conductive with normal otologic examination

23. Pearls • Presbycusis • High frequency hearing loss • Worse in loud environments • Speech recognition more affected than hearing • Neural pathway pathology • Associated symptoms: neural causes