Conductive Hearing Loss

1. See Also
   1. Hearing Loss
   2. Sensorineural Hearing Loss
   3. Hearing Impairment Severity Scale
2. Epidemiology
   1. Age of onset under age 40 years
   2. Most common cause of Hearing Loss
3. Causes
   1. Infection (and sequelae)
      1. Middle ear effusion
         1. Otitis Media with Effusion (20-30 db Hearing Loss)
         2. Eustachian Tube Dysfunction
      2. Otitis Externa
      3. Mastoiditis
   2. Obstruction
      1. Cerumen Impaction (complete ear canal Occlusion)
      2. Ear Canal Foreign Body
      3. External canal oxostoses (Surfer's Ear)
   3. Sclerosis
      1. Otosclerosis
      2. Severe Myringosclerosis (Tympanosclerosis)
   4. Neoplasms and Masses
      1. Cholesteatoma
      2. Glomus tumor
      3. Bony growths of ear canal (exostosis or osteoma)
   5. Trauma
      1. Ossicular Chain Disruption
      2. Tympanic Membrane Perforation
         1. Head Trauma
         2. Barotrauma (Rapid descent in air or water, straining)
4. Symptoms
   1. Minor impaired word understanding
      1. See Hearing Impairment Severity Scale
   2. Hearing not impaired in a noisy environment
   3. Patient does not raise their voice
5. Signs
   1. Otoscopy
      1. Abnormal Ear Canal or Tympanic Membrane
   2. Weber Test (Tuning Fork at Midline) Abnormal
      1. Sound radiates to the ear with conductive loss
      2. Conductive loss shuts out noisy environment
   3. Rinne Test (Tuning fork on Mastoid) Abnormal
      1. Bone Conduction is better than Air Conduction
6. Diagnostics
   1. Tympanogram
   2. Audiogram
7. Management
   1. Treat Suppurative Otitis Media if present
   2. See Eustachian Tube Dysfunction
   3. Otolaryngology for suspected structural disorders
8. References
   1. Cunningham (2017) N Engl J Med 377(25): 2465-73 [PubMed]
   2. Edmiston (2013) BMJ 346: f2495 +PMID:23618723 [PubMed]
   3. Uy (2013) Ann Intern Med 158(7): ITC4-1 +PMID:23546583 [PubMed]
   4. Michels (2019) Am Fam Physician 100(2): 98-108 [PubMed]