208 ENT Flashcards
Which part of the ear is affected in conducive hearing loss?
Outer/middle ear
Which part of the ear is affected in senrorineural hearing loss?
Inner ear/cochlear/auditory nerve
What is a positive Rinne’s test?
When air conduction is greater than bone conduction
Which ear does the pt hear the sound in in a Weber’s test in a unilateral conductive hearing loss?
In the affected ear
Which ear does the pt hear the sound louder in a Weber’s test in a unilateral sensorineural hearing loss?
Away from the affected ear
What is myringosclerosis?
Chalky white patches on the eardrum which are benign and a result of previous damage
How many dB amplification does the pinna provide at 4kHz?
3dB
How many dB of amplification does the concha provide at 4-5kHz?
10dB
How many dB of amplification does the ear canal provide at 2.5kHz?
10dB
What is the net gain of amplification at 2.5kHz as the sound waves travel through the ear to the auditory nerves?
20dB
Name a cause of congenital conductive hearing loss
Atresia
What is the most common cause for sensorineural hearing loss?
Increasing age
Name 2 drugs which can cause sensorineural hearing loss
Gentamycin
Furosemide
Name 3 inflammatory conditions which can cause lesions of CN VIII and therefore a sensorineural hearing loss
(4 listed)
TB
Sarcoidosis
Neurosyphilis
Carcinomatous meningitis
What is otosclerosis?
Inherited disease where a small focus of spongy bone developing at fissula ante finestrum which maintly causes conductive hearing loss
What is the treatment of otosclerosis?
Surgery - fixation of the stapes with a prosthesis
Hearing aid
What is another name for secretory otitis media with effusion?
Glue ear
What condition can reoccur in pt’s with glue ear?
Otitis media
What are the treatment options for glue ear?
4 listed
Watch and wait
Grommets
Grommets + adenoidectomy
Hearing aid
Which cells deteriorate in presbyacusis?
Hair cells / ganglion cells
What causes an acoustic neuroma?
Slow overgrowth of Schwann cells which cover the vestibular/cochlear nerves
Where do acoustic neuromas tend to reside once they have reached around 2-3cm?
Cerebellopontine angle
What type of hearing loss does acoustic neuromas cause?
Unilateral sensorineural hearing loss
What is the outcome of an untreated acoustic neuroma?
Hydrocephalus - the tumour grows into the cerebellopontine angle and occludes the cerebral aqueduct and 4th ventricle
What are the 2 factors thought to contribute to the formation of a cholesteatoma?
Epithelial migration coupled with negative middle ear pressure
Which direction do cholesteatomas tend to grow/migrate?
Superomedially
In which trimester of pregnancy can a congenital cholesteatoma start forming?
1st trimester
What are the possible complications of an untreated cholesteatoma?
(4 listed)
Facial nerve paralysis
Meningitis
Mastoid abscess
Brain abscess
What are the 3 red flags of vertigo?
- Any cranial nerve symptoms
- Weakess/ numbness in limbs
- Gaze evoked nystagmus
What is the most common cause of isolated vertigo?
BPPV - benign paroxysmal positional vertigo
Which manoeuvre is performed to diagnose BPPV?
Dix-Hallpike
Which manoeuvre is curative in most pt’s with BPPV?
Epley
What is the cause of BPPV?
Otoconia felling off the macula to create a mass behind the cupula
What causes Meniere’s disease?
Build up of endolymphatic fluid in the inner ear due to restricted flow which causes distension and disruption to normal neuroepithelia. Also known as endolymphatic hydrops
What is the progression of symptoms in Meniere’s disease?
Hearing loss and tinnitus followed by vertigo
What causes the ionic disequilibrium in Meniere’s disease? What is the outcome of this?
Endolymph and perilymph mixing together which causes stimulation and damage of the neuroepithelium
What is betahistidine used to treat?
Prophylaxis of vertigo in Meniere’s disease
What are the surgical options for Meniere’s disease?
4 listed
- Grommets + gentamycin into the middle ear
- Saccus decompression (opening of the endolymphatic sac)
- Chemical labyrinthectomy
- Bony labyrinthectomy
What causes vestibular neuritis?
Inflammation of the vestibular nerve by a virus or arterial occlusion
What are the symptoms of vestibular neuritis?
Severe vertigo
N&V
What distinguishes vestibular neuritis from labyrinthitis?
Vestibular neuritis has preserved auditory function
What is prochloperazine used in the treatment of?
Vestibular neuritis - vestibular sedation
What can be observed in an examination of a patient with vestibular neuritis/labyrinthitis?
Nystagmus in all directions,
Name 3 introcerebral diseases which can cause vertigo
MS
Migraine
Posterior circulation stroke
Which ear is effected in a left beating nystagmus?
Right - the fast phase defines the nystagmus but the slow phase moves towards the affected side due to the unopposed action of the extraocular muscles
Where in the brainstem is the vestibular nucleus found?
Pons
