ENT Flashcards
Describe the anatomy of the inner and outer ear.
Describe the anatomy of the tympanic memrbane.
What are the DDx for dizziness?
What are the DDx for otalgia?
What are the DDx for hearing loss?
What are the DDx for tinnitus?
What are the 5 D’s of vertebrobasilar insufficiency?
- Drop attacks
- Diplopia
- Dysarthria
- Dizziness
- Dysphagia
What are the DDx for a neck mass?
Describe normal hearing physiology?
- Conductive pathway (external auditory canal to cochlea): air conduction of sound energy down the EAC → vibration of the tympanic membrane (area effect) → sequential vibration of the middle ear ossicles: malleus, incus, stapes (lever effect) → transmission of amplified vibrations from the stapes footplate in the middle ear to the oval window of the cochlea in the inner ear → pressure differential on cochlear fluid creates movement along the basilar membrane within the cochlea from base to apex
- Neural pathway (nerve to brain): basilar membrane vibration stimulates overlying hair cells in the organ of Corti → stimulation of bipolar neurons in the spiral ganglion of the cochlear division of CN VIII → cochlear nucleus → superior olivary nucleus → lateral lemniscus → inferior colliculus → Sylvian fissure of temporal lobe
What are the DDx for a neck mass?
- congenital
- lateral (branchial cleft cyst, lymphatic/venous/venolymphatic malformation)
- midline (thyroglossal duct cyst, dermoid cyst, laryngocele)
- infectious/inflammatory
- reactive lymphadenopathy (20 to tonsillitis, pharyngitis)
- infectious mononucleosis
- Kawasaki, Kikuchi, Kimura
- HIV
- salivary gland calculi, sialadenitis
- thyroiditis
- granulomatous disease
- mycobacterial infections
- Sarcoidosis
- neoplastic
- lymphoma
- salivary gland tumors
- thyroid tumors
- metastatic malignancy (“unknown primary”)
Describe the difference between inflammatory vs malignant neck masses?
Name the anatomy
name the anatomy
Name the anatomy
Name the anatomy
Name the anatomy
What parts of the ear do conductive and sensorineural hearing loss affect?
- Conductive losses affect outer and middle ear function
- Sensorineural losses affect the cochlea in the inner ear.
How do cochlear implants work?
Cochlear implants provide a direct electrical stimulation to the auditory nerve fibres in the cochlea to reproduce the action of the hair cells that are damaged in cases of sensorineural loss.
What are some causes of hair cell damage in the ear?
Causes of hair cell damage include:
- gentamicin toxicity
- bacterial meningitis
- skull fracture
- noise exposure
- presbycusis
- genetic syndromes
- hereditary deafness, and
- many of the ‘unknown’ causes of hearing loss.
Otosclerosis results in what type of hearing loss?
Otosclerosis results from an overgrowth of bone in the middle ear fixing the foot plate of the stapes at the oval window, hence resulting in a conductive hearing loss.
