Inner ear Flashcards
What are acquired degenerative diseases of the inner ear?
- Presbycusis
- Meniere’s disease
What are infective causes of inner ear disease?
- Labrynthitis
- Spread from otitis media/cholesteatoma
- Other infections - e.g. mumps
What are vascular causes of inner ear disease?
- Occlusion
- Vasculitis
What are traumatic causes of inner ear disease?
- Acoustic - acute/chronic
- Direct/labyrinthine concussion
- Temporal bone fracture
- Round/oval window rupture
- Drug toxicity
- Surgical
What are metabolic causes of inner ear disease?
- Diabetes mellitus
- Thyroid disease
What is presbycusis?
A degenerative disorder - used to be described as old age hearing loss in both ears. It is characterised by gradual hearing loss, with or without tinnitus
What is the pathophysiological process behind presbycusis?
It can be due to the loss of outer hair cells (sensory), loss of the ganglion cells (neural), strial atrophy (metabolic) or it can be a mixed picture
How would you treat presbycusis?
Hearing aid
What is the typical characteristic of hearing loss caused by presbycusis?
Struggling to hear in places where there is increased background noise
What is labrynthitis?
Acute vestibular failure/Vestibular Neuronitis
Acute inflammation of the inner ear that usually follows a simple URTI
Wht can cause labrynthitis?
- URTI
- Middle ear infection
- Intracranial sepsis
What are features of labyrinthitis?
Sudden attck of unilateral vertigo, accompanied by vomiting
What signs can present in labrynthitis?
- Nystagmus away from affected side
- Hearing loss
Which way will nystagmus go in someone with labrythitis?
Away from affected side - https://www.youtube.com/watch?v=yo-zA1CuKUI
How would you manage someone with suspected labrynthitis?
- Bed Rest
- Vestiular sedatives - Bucastem, cyclizine
How long does it take labrynthitis to resolve?
1-2 days, can take several weeks to fully resolve - residual imbalance with rapid movements for following months
What is a severe complication of labrynthitis?
Total vestibular destruction
What are examples of medications that are ototoxic?
- Gentamicin
- Diuretics
- Malarial drugs
- Co-trimoxazole
- Metranidazole
What is Miniere’s Disease?
A disorder of the inner ear that is characterized by episodes of feeling like the world is spinning (vertigo), ringing in the ears (tinnitus), hearing loss, and a fullness in the ear
What is thought to be the cause of miniere’s disease?
Distention of the membranous labyrinth/endolymphatic space. This is thought to cause small tears in Reissner’s membrane, leading to mixture of endo and periplymph
What are the features of miniere’s disease?
Attacks of the following triad triad of symptoms:
- Tinitus
- Hearling loss
- Vertigo
Also includes:
- Nausea and vomiting
- Feeling of fullness in the ear
How long can miniere’s attacks last?
Acute spinning vertigo for 30 minutes to 4 hours
What type of hearing loss occurs in miniere’s disease?
Sensorineural hearing loss
What features may precede attacks in Miniere’s disease?
- Tinnitus
- Feeling of fullness in the ear
What happens over time in menieres disease?
Attacks of vertigo and tinnitus become permanent
How would you investigate someone with suspected meniere’s disease?
- Clinical history
- Electrocochleography
- Endolymphatic space MRI
- Exclude other causes of vertigo
What are peripheral causes of vertigo?
- Meniere’s disease
- BPPV
- Labyrinthitis/Vestibular Failure
- Cholesteatoma
- Middle ear disease
- Drugs
- Vascular insufficiency
- Post ear-surgery/trauma
What are central causes of vertigo?
- Acoustic neuroma
- Vestibular neuronitis
- MS
- Head Injury
- Inner ear syphillis
- Migraine
- Vascular occlusion
- Epilepsy
How would you manage meniere’s disease acutely?
Vestibular sedatives - bucastem, chlortalidone
How would you manage meniere’s disease in the long-term?
- Betahistine
- Diuretics
- Avoid caffeine and salt
-
Consider destructive interventions
- Intratympanic gentamicin
- Vestibular nerve section
- Labrynthectomy
What is benign paroxysmal positional vertigo?
A disease which is characterised by episodic veritgo that occurs when the head is moved in certain directions
What is thought to be the cause of BPPV?
Dislodged otoliths settling in the posterior semi-circular canal, and with certain movements this causes irritation of the sensory epithelium
How would you approach assessing vertigo?
- Is it true vertigo?
- Is there middle ear pathology?
- Is it acute?
- Is it episodic?
What are features of BPPV?
Attacks of sudden rotational vertigo lasting >30 seconds
What are causes of BPPV?
- Idiopathic
- Middle ear disease
- Head injury
- Otosclerosis
- Post viral illness
- Stapes surgery
What is important to exclude before making the diagnosis of BPPV?
- No persistent vertigo
- No speech, visual, sensory or motor problems
- No Tinnitus, Headache, Ataxia, facial numbness, dysphagia
- No vertical nystagmus
How would you investigate suspected BPPV?
Dix-Hallpike maneuvre
What is involved in the Dix-Hallpike maneuvre?
https://www.youtube.com/watch?v=kEM9p4EX1jk
Patient sits on couch facing examiner. They are then quickly laid flat , the examiner supports patients head and rotates through 30 deg and inclines the head downwards
What is classed as a positive Dix-Hallpike test?
https://www.youtube.com/watch?v=7ePecb9azS4
Rotational nystagmus
How would you manage someone with BPPV?
Usually self limiting
- Vestibular habituation exercises
- Epley Maneuvre
Rarely
- Surgery - posterior semicircular canal denervation/obliteration
What is an acoustic neuroma?
Indolent, histolologically benign subarachnoid tumours that cause problems due to local pressure - Behave like SOLs
They are basically schwannomas of the vestibular part of the VIII cranial nerve
What are classic features of an acoustic neuroma?
Progressive ipsilateral
- Tinnitus
- Sensorineural deafness
What are features of a large acoustic neuroma?
- Ipsilateral cerebellar signs
- Increased ICP
Think steps song…
What cranial nerves are at risk in the development of an acoustic neuroma?
V, VI, VII, VIII
When would you supect an acoustic neuroma?
Any patient with unilateral senosorynerual hearing loss or tinnitus that cannot be explained by another cause
What investigations would you do if you suspected acoustic neuroma?
MRI - all those with unilateral hearing loss/tinnitus
What might be a differential diagnosis in someone presenting with features of an acoustic neuroma?
Meningioma
How would you manage an acoustic neuroma?
- Can watch and wait - repeat MRI scan every 4-6 months
- Surgery - remove neuroma
- Sterotactic radiotherapy
What are the three branches that are given of from the facial nerve as it travels through the temporal bone the stylomastoid foramen?
- Greater petrosal nerve
- Nerve to stapedius
- Chorda tympani
What does the greater petrosal nerve supply?
Lacrimal gland
What does the nerve to stapedius supply?
Stapedius muscle - dampens loud sounds through stapedial reflex - tenses stapedius muscle which reduces the amount the stapes vibrates
What does the chorda tympani supply?
Taste sensation to the anterior 2/3rds of the tongue
If someone was experiencing vertigo, what examinations would you want to perform?
Test cranial nerves
- Nystagmus
- Gait
- Romberg’s
- Unterberger’s
- Dix hallpike
What is important to distinguish in an apparent facial nerve palsy?
Whether it is UMN or LMN
What are intracranial causes of facial nerve palsy?
- Brainstem tumour
- Stroke
- Polio
- MS
- Cerebellopontine angle lesions - acoustic neuroma, meningitis
What are intratemporal causes of facial nerve palsy?
- Otitis media
- Ramsay hunt syndrome
- Cholesteatoma
What are infratemporal causes of facial nerve palsy?
- Parotid tumours
- Trauma
What are causes of facial nerve palsy’s besides infra/intratemporal and intracranial causes?
- Lyme disease
- Sarcoidosis
- Guillain-Barre
- Herpes
- Diabetes
- Bell’s Palsy
How would you distinguish an UMN facial nerve palsy from a LMN facial nerve palsy?
UMN lesion spares the eyebrows/forehead region, as the UMN for the facial nerve is bilaterally represented in the brain. Therefore, if a lesion occurs in one of the hemispheres, the other still supplies the eyebrows
What is characteristic about a LMN facial nerve palsy?
Ipsilateral total facial muscle paralysis
What are signs of facial nerve palsy?
- Facial muscle paralysis
- Hyperacusis - loss of stapedius reflex
- Loss of lacrimation
- Decreased saliva production
- Cause - cholesteatoma, herpes zoster signs, trauma
What is thought to be the process behind the developent of bell’s palsy?
Inflammatory oedema from entrapment of VII nerve in the narrow facial bony canal, for exampe in viral polyneuropathy
How does Bell’s palsy usually present?
Sudden onset
- Sagging mouth
- Dribbling from affected side
- Watering/dry eyes
- Impaired brow wrinkling, blowing, whistling, lid closure, taste, speech
What can often preceed a Bell’s palsy?
URTI
How would you manage a Bell’s Palsy?
- Tape eye closed
- Artificial tears
- Prednisolone
- Consider high dose aciclovir - if zoster cause
What features would you ask about to screen for Ramsay Hunt Syndrome (herpes zoster infection)?
- Preceding ear pain
- Stiff neck
- Reddish auricle
- Zoster vesicles around the ear
- Vertigo
- Sensorinerual deafness
- Severe VII nerve paralysis
What are the different groups of causes of facial nerve palsy?
- Intracranial
- Intratemporal
- Infratemporal
- Others
What are extrinsic causes of tinnitus?
- Insect in external acoustic meatus
- AV malformations
What are intrinsic causes of tinnitus?
- Idiopathic central tinnitus
- VIII nerve tumours
- Temporal lobe epilepsy
What are peripheral causes of tinnitus?
- Drugs
- Labyrinthitis
- Trauma
- Vascular
- Presbycusis
- Meniere’s
- Noise
- Otosclerosis
How would you assess hearing loss?
Use following
- Is there external ear pathology?
- Is the tympanic membrane normal?
- Tuning fork test
- Is the hearing normal?
- Is there conductive/snesory loss?
If you were presented with someone who was complaining of dizziness, what are the two main things you you want to establish to narrow down your differencial diagnosis?
- Is this true vertigo? - illusion of movement rather than lightheadedness
-
IF TRUE VERTIGO - What is the duration of the feeling of vertigo?
- Seconds - Minutes - BPPV
- Minutes - Hours - Meniere’s or Vestibular Migraine
- Weeks - Labyrinthitis
What is the house brackmann scale?
A score to grade the degree of nerve damage in a facial nerve palsy. The measurement is determined by measuring the upwards (superior) movement of the mid-portion of the top of the eyebrow, and the outwards (lateral) movement of the angle of the mouth
What is grade one of the house brackmann scale?
Normal facial function in all areas
What is grade two of the house brackmann scale of facial nerve palsy?
Mild dyfunction - Slight weakness noticeable on close inspection
What is grade three of the house brackmann scale of facial nerve palsy?
Moderate dyfunction - Obvious weakness but not disfiguring at rest
What is grade four of the house brackmann sclae?
Moderate-to-severe dysfunction - incomplete eye closure, obvious asymmetry
What is grade five on the house brackmann scale for facial nerve palsy?
Severe dysfunction - Incomplete eye closure, only tewitch to gross motor movement
What is grade six of the house brackmann scale of facial nerve palsy?
Total paralysis
What is the house brackmann sclae used for in facial nerve palsy?
Determine prognosis in terms of potential for recovery
