Sensory Disorders: Middle and Inner Ear

Sensory Disorders: Middle and Inner Ear

• Ear Function: The ear has two primary functions: hearing and balance.
• Middle Ear Structure: Composed of the eardrum (tympanic membrane) and three ossicles (malleus, incus, and stapes). Connected to the nasopharynx via the Eustachian tube.
• Inner Ear Structure: Located within the temporal bone, separated from the middle ear by the oval window. Contains the cochlea (hearing) and semicircular canals (balance). Cranial nerves VII (facial) and VIII (vestibulocochlear) are involved.
• Balance Systems: Visual, vestibular, and proprioceptive systems provide balance input to the brain; problems in any can lead to balance loss.
• Nurses Responsibilities: Nurses should be knowledgeable about ear disorders, infections, tumors, balance and coordination issues.

Types of Ear Disorders

• Hearing Loss:
  • Causes (Conductive): Otitis media, otosclerosis, foreign body (impacted cerumen)
  • Causes (Sensorineural): Damage to cranial nerve VIII
  • Causes (Combined): Combination of conductive and sensorineural problems
  • Aging Impacts: Thickened tympanic membrane (loss of elasticity), loss of sensory hair cells, limited ossicle movement.
  • Environmental/Workplace Impact: Noise exposure.
  • Cerumen Variation: Cerumen (earwax) and ear canal color vary by race/skin tone; normal variations should be recognized.

Middle Ear Conditions

• Acute Otitis Media (AOM): Viral or bacterial middle ear infection.
  • Symptoms: Ear pain, pressure, fever, headaches, conductive hearing loss, purulent/bloody drainage (if eardrum perforation).
  • Physical Exam: Redness, bulging eardrum, inability to see normal landmarks.
  • Medical Management: Systemic antibiotics, analgesics, heat application, decongestants.
  • Surgical Management: Myringotomy (eardrum incision), grommet placement for pressure equalization.

Inner Ear Conditions

• Vertigo: Sensation of motion (self or surroundings).
  • Benign Paroxysmal Positional Vertigo (BPPV): Disruption of calcium carbonate crystals in the semicircular canal; position-related vertigo; sudden onset, lasting weeks to years.
    • Treatment: Bed rest, short-term meclizine.
  • Ménière's Disease: Episodic vertigo, tinnitus, fluctuating sensorineural hearing loss.
  • Labyrinthitis: Inner ear labyrinth inflammation (often secondary to AOM).
    • Symptoms: Severe sudden vertigo, nausea, vomiting, possible hearing loss and tinnitus.
    • Treatment: Bed rest in dark environment, meclizine/dimenhydrinate for symptoms, antibiotics if needed.

Assessment and Risk Factors

• Middle Ear Risk Factors: Recurrent colds/otitis media, enlarged adenoids, trauma, changes in air pressure (diving, flying).
• Inner Ear Risk Factors: Viral/bacterial infections, ototoxic medications.
• Expected Findings (AOM): Enlarged adenoids, report of colds, ear pain, hearing loss, ear fullness/pain, red/inflamed ear canal/eardrum (bulging), fluid/bubbles behind eardrum, difficulty seeing light reflex, fever.
• Expected Findings (Inner Ear): Hearing loss, tinnitus, dizziness/vertigo, vomiting, nystagmus.