Ear Disorders Flashcards
What is the functional unit of the inner ear?
Organ of Corti
What is the tympanic reflex?
Protection of the cochlea via muscle contraction in response to loud sounds
T or F: The tympanic reflex will help protect your ears from gun shot sounds.
F; The reflex is not fast enough to protect the cochlea (designed for slow building sounds)
T or F: You can listen and talk at the same time.
F; Muscle will contract while speaking (can’t hear others)
How does sound produce stimulation in the cochlea hair cells?
- Sound waves cause vibration of the ossicles
- Ossicles (specifically Stapes) vibrates the basilar membrane at a complementary frequency
From first bone to last, how are the osiccles vibrated from a sound wave?
- Malleus
- Incus
- Stapes
Where are different frequencies (high vs low) percieved along the basilar membrane?
- High: percieved towards the beginning of the basilar membrane
- Low: percieved towards the end of the basilar membrane
How does persistant loud sounds affect hearing over time?
Loud sounds will damage the proximal portion of the basilar membrane leading to a loss of high pitch hearing over time.
If a tumor exist in the ear, what pathologies might be observed?
Facial nerve suppression
What are the 3 classifications of hearing loss? (Common differential)
- Conductive
- Sensorineural
- Mixed
What are common differentials for diagnosis of Sensorineural hearing loss?
- Prebycusis
- Noise-induced
- Temperature threshold shift > permanent
- Acoustic trauma (one-time event)
- Ototoxicity
- Acoustic neuroma
- Menierie’s disease
T or F: Patients with sensorineural hearing loss demonstrate AC>BC.
T; No change in conductive hearing should be observed
What is Acoustic Neuroma?
Benign tumor of the acoustic nerve that commonly causes U/L sensorineural hearing loss
How might a patient with Acoustic neuroma present?
Sudden onset U/L hearing loss with no outward/visible causes.
What is commonly used to DX & TX Acoustic Neuroma?
DX: MRI/CT (pay attention to internal auditory canal)
TX: Steroids (prevent viral infection), Radiotherapy, Microsurgery
What is the S/Sx triad associated with Menierés Disease?
- Rotational vertigo (At least one episode lasting 20+ minutes)
- Hearing loss (Fluctuating, low-frequency and progressive)
- Tinnitus
What is Menierés disease?
Malfunction of endolymph volume regulation in the scala media (cochlear duct), results in:
- Disruption of basilar membrane movement
- Mixing of endoymph and perilymph
What are dietary manipulations that can be useful in treating Menierés disease?
- Low sodium diet
- Water intake
- Caffeine restriction (includes chocolate)
- Alcohol restriction
What is the common treatment for mild/moderate cases of Menierés disease?
Low Sodium diet and Low-dose dieuretic
How does Weber testing present with conductive hearing loss?
Will lateralize to the affected ear
How does Weber testing present in sensorineural hearing loss?
Will lateralize to the unaffected ear
Why is tympanometry and important screening tool in evaluating a patient’s hearing?
evaluates details of middle ear function and middle ear reflexes for possible dysfunction
What are the three main types of tympanograms found with tympanometry?
Type A: considered normal hearing, peak at 0 pressurization
Type B: observed with AOM, decreasing plateau
Type C: observed with negative pressure, one peak during negative pressurization
How does otosclerosis affect a Type A tympanogram?
DEC amplitude (more rigid ear drum)
If the ear drum is more flaccid, how will a Type A tympanogram change?
Amplitued of one peak will INC
What are systemic causes of otitis externa?
- Seborrheic dermatitis
- Psoriasis
- Atopic dermatitis
- Lupus
- Acne
“SPALA”
What are local causes of otitis externa?
Contact Dermatitis (i.e. topical anti-infectives, hearing aids, ear plugs)
T or F: When cleansing the ear canal, do not flush unless the TM is fully visible.
T
What other S/Sx should be evaluated for when managing otitis externa?
- Otitis media (esp. with URI or age <2 y/o)
- Fever (>101 °F)
- Severe pain or grandulation tissue
- Immune suppression (i.e. DM, corticosteroids, HIV)
What topical treatments are avaiable for otitis externa?
- Acidification solution (with/without)
- Homemade solution (1/3 distilled water, 1/3 white vinegar, 1/3 rubbing alcohol)
- ABX
- Polymycin B/Neomycin
- Gentamicin
- Ofloxacin
- Ciprofloxacin
- Ciprodex
What should be evaluated prior to using Polymycin B/Neomycin solutions for treatment of otitis externa?
R/O Allergies
Why is Ofloxacin considered a good treatment for otitis externa? (think coverage)
Very effective against pseudomonas aeroginosa
T or F: No oral ABX should be used to treat otitis externa.
T
