PBL 5 Flashcards
What is tinnitus?
A sensation of sound when there is no auditory stimulus
can occur without hearing loss and results from heightened awareness of neural activity in the auditory pathways
What is vertigo?
A sensation of whirling and loss of balance that is due to inner ear dysfunction
either a sensation of movement without movement or an exaggerated sense of motion
What symptoms accompany vertigo?
- nausea
- vomiting
- palor
- sweating
- nystagmus
What is nystagmus?
rapid involuntary movements of the eye
What causes vertigo?
vestibular dysfunction
either a peripheral vestibular cause or a central cause
What are the symptoms of tinnitus?
Patient describes a hissing or a ringing in their ears
What diseases can be associated with tinnitus?
- vascular malformation (e.g. aneurysm)
- vascular tumour
What causes tinnitus?
awareness of neural activity in the auditory pathways that our brains are made aware of.
What is Meniere’s disease?
excessive accumulation of endolymph in the membranous labyrinth causing a distortion of hearing
What are the clinical features of meniere’s disease?
- tinnitus
- fluctuating sensoneural hearing loss
- vertigo
- sensation of ear fullness
Describe the symptom of tinnitus in meniere’s disease
typically a low buzzing or blowing sound that is frewquently louder before the attack of vertigo
attacks not precipitated by positional changes and may be months or weeks apart
Descibe the symptom of fluctuating sensorineural hearing loss in meniere’s disease
in early stages, hearing loss fluctuates with return to normal after the rupture heals
remissions and exacerbations typical
Describe the symptom of vertigo in meniere’s disease
episodes may be preceeded by sensation of pressure in the ear, increased hearing loss or increased tinnitis
usually sudden onset with maximum intensity reached in a few minutes
Usually lasts for an hour or more
What is a schwannoma of the vestibulocochlear nerve?
An acoustic neuroma
= a benign slow-growing tumour of the schwann cells surrounding the vestibulocochlear nerve (CNVIII) and facial nerve (CN VII)
tumour usually arises from the vestibular branch
What are the clinical features of an acoustic neuroma?
- unilateral sensorineural hearing loss (most common)
- vertigo
- facial numbness
- tinnitus
larger tumours may cause headaches, coordination difficulties, obstructive hydrocephalus
What treatments can be given in Meniere’s disease to provide symptomatic relief?
During acute attacks:
- antiemetics
- anticholinergics
Between acute attacks:
- eating a low-sodium diet
- using diueretics
- smoking cessation
- stress management
- caffeine elimination
What surgical interventions can be given to patients with meniere’s disease?
Shunts can be placed to drain excessive endolymph
removal of portions of the vestibulococchlear nerve and destruction of the membranous labyrinth are options
What treatment can be given for an acoustic neuroma?
- chemotherapy/radiotherapy
- surgery -using sub-occipital retrosigmoid approach
What is the sub-occipital retrosigmoid approach
Part of the occipital bone behind the ear is removed to gain access to the tumout
retrosigmoid = requires the surgeon to go under the sigmoid sinus in the brain to reach the internal acoustic meatus
Describe the course of the vestibulocochlear nerve
CN VIII leaves the CNS at the level of the pons and travels via the internal acoustic meatus and splits into two branches
What are the branches of the vestibulocochlear nerve and what are their functions?
vestibular branch
> balance (sensory)
cochlear branch
> hearing (sensory)
Describe the course of the facial nerve
CN VII originates from the pons anf exits the skull via the internal acoustic meatus
reaches the posterior wall of the middle ear then passes inferiorly to exit the skull at the stylomastoid foramen
Then enters the parotid gland, giving rise to the terminal branches
What are the branches of the facial nerve and what are their function?
- Temporal
- Zygomatic
- Buccal
- Marginal mandibular
- Cervical
> motor control of the facial muscles
sensation of taste to the anterior 2/3 of the tongue
parasympathetic division supplying various glands
Which glands does the facial nerve supply?
- submandibular
- sublingual
- nasal
- palatine
- lacrimal
- pharyngeal
Why does surgery on the vestibulocochlear nerve pose a risk to the facial nerve?
Both travel along the internal acoustic meatus, which is often the location of the tumour.
The size of the tumour can affect the surrounding structures
What is facial palsy?
The loss of muscle control on one side of the face, which may be temporary or permanent
What is a tarsorrhaphy?
The orbicularis oculi muscle will be affected which will make it difficult for patients to close their eyes resulting in drying of the eye and cornea
This procedure partially sews the eyelids together to narrow the eyelid opening
