Ear and Eye (ENT 2) Flashcards
What are the four categories of dizziness?
Vertigo
Presyncope
Disequilibrium
Light headedness
What is vertgio? How may this be described?
Imbalance of tonic vestibular signal
False sense of motion / spinning sensation
What is disequilibirum?
Symmetric vestibular loss, proprioceptive loss, cerebellar damage
Off balance / wobbly
what is presyncope?
Diffusely diminished blood flow / blood
Feeling of losing consciousness / blacking out
What is psychogenic?
Abnormality in the integration of afferent signal by CNS
Vague sumptoms
Possibly feeling disconnected with the environment
What may cause disequilibrium?
Cerebellar damage
Basal ganglia lesion
Cerebellar damage
What may cause presyncope?
Orthostatic hypotension
Hypoglycaemia
Cardiac arrhythmia
List some peripheral causes of vertigo
Benign paroxsymal positional vertigo (BPPV) Vestibular neuritis Meniere disease Otoscleroris Lavrynthitis
List some central causes of vertigo
Vestibular migraine CV disease Cerebellopontine angle and posterior fossa meningiomas MS Acoustic neuroma
How does BPPV present?
Attacks of sudden rotational vertigo lasting >30s are provoked by head turning
Other otological symptoms rare
How is BPPV diagnosed?
Establish important negatives:
No persistent vertigo
No speech, visual, motor or sensory problems
No tinnitus, headache, ataxia, facial numbness, dysphagia
Hallpike test +ve
What is an acoustic neuroma?
Usually painless benign subarachnoid tumours that cause problems by local pressure, and then behave as SOL
Rare = 1 / 100,000 / year
Where do acoustic neuromas usually arise?
Superior vestibular Schwann cell layer
Sometimes called vestibular schwannoma
How do acoustic neuromas present?
Progressive ipsilatural tinnitus +/- sensorineural deafness (cochlear nerve vompression)
Disequilibrium common
Vertigo rare
Trigeminal compression above tumour may give numb face
What investigations are done for an acoustic neuroma?
MRI for all those with unilateral tinnitus / deafness
Key differential = meningioma
What is the management of an acoustic neuroma?
Surgery is difficult and not often needed eg if elderly
Methods of preserving hearing and facial nerve eg stereotactic radiosurgery
What is tinnitus?
Perception of sound in the ears or head where no external source of the sound exists
How can tinnitis be divided?
Objective (audible to examiner) - rare
Subjective (audible only to pt)
What can cause objective tinnitis?
1) Vascular disorders = Pulsatile vibratory sounds
AV malformations, glomus tumours
2) High output cardiac states = Pulsatile sounds
Pagets, hyperthyroid, anaemia
3) Myoclonus of palatal of stapedius / tensor tympani muscles = audible click
4) Patulous eustachian tube = prolonged opening, causing abnormal sound transmission to ear
What can cause subjective tinnitis?
Most commonly associated with disorders causing sensorineural hearing loss eg presbycusis, noise induced hearing loss, Menieres (unilateral)
Conductive deafness less common eg impacted wax, otosclerosis
Otitis media with effusion Thyroid dysfunction DM MS Acoustic neuroma Anxiety
List some ototoxic drugs?
Cause bilateral tinnitis with associated hearing loss
Cisplatin and aminoglycosides = permanent hearing loss
Aspirin, NSAIDs, quinine, macrolides and loop diuretics are associated with tinnitus and reversible hearing loss
List some aminoglycosides
Gentamicin Tobramycin Plazomicin Streptomycin Neomycin
What is the pathophysiology of tinnitis
Poorly understood
Spontaneous otoacoustic emissions
Altered or increased spontaneous activity of auditory nerve
Inappropriate feedback pathways in auditory-limbic system
What tests can be done for tinnitis?
Audiometry
Tympanogram
MRI for unilateral tinnitus to exclude acoustic neuroma
What is the treatment of tinnitus?
Treat any underlying cause
Explain - it common and usually improves with time via habituation
Hearing aids - if hearing loss >35db, improves perception of background noise and makes tinnitus less apparent
Psychological support eg sound therapy (radio / fan use to mask sound)
CBT
What is glaucoma?
Group of eye diseases associated with acute or chronic destruction of the optic nerve with or without increased intraocular pressure (IOP)
Aqueous humor is produced by the ciliary body on the iris, flows from the posterior chamber through the pupil into the anterior chamber, and then drains back into the venous system via the trabecular meshwork in the angle of the anterior chamber.
- Any process that can disrupt the flow can lead to optic nerve damage
What are the two main types of glaucoma?
Open angle (90%) = slowly progressive, initially often asymptomatic, but leads to peripheral vision loss over time (peripheral to central)
Acute angle closure glaucoma
What is acute angle closure glaucoma?
Angle of anterior chamber narrows narrows acutely causing a sudden rise in IOP to >30mmHg (normal range is 15-20)
Pupil becomes fixed and dilated and axonal death occurs
What is primary vs secondary acute angle closure glaucoma?
Primary = anatomical predisposition Secondary = pathological processes eg traumatic haemorrhage pushing the posterior chamber forwards
What factors predispose acute angle closure glaucoma?
Hypermetropia (long-sightedness)
Pupillary dilatation
Lens growth associated with age (typically 40-60yr)
Asian
How does acute angle closure glaucoma present?
severe pain: may be ocular or headache
decreased visual acuity
symptoms worse with mydriasis (e.g. watching TV in a dark room)
hard, red-eye
haloes around lights
semi-dilated non-reacting pupil
corneal oedema results in dull or hazy cornea
systemic upset may be seen, such as nausea and vomiting and even abdominal pain
What is the management of acute angle closure glaucoma?
Urgent referral to opthalmologist for gonioscopy - angle between iris and cornea checked (drainage angle)
Triad of:
1) Beta blockers to suppress aqueous humour production eg timolol 0.5%
2) Pilocarpine 2-4% drops/2hrs - pupillary constriction opens trabecular mesh work and increases drainage
3) 500mg IV acetazolamide stat then 250mg/8hr PO/IV - reducing aqueous humour formation
Admit to monitor IOP
What is done once IOP is controlled in acute angle closure glaucoma?
Peripheral iridectomy - a piece of iris is removed (at ‘12 o clock’) in both eyes to allow aqueous to flow
What are some complications of acute angle closure glaucoma?
Visual loss
Central retinal artery or vein occlusions
Repeated episodes
What is the management of open angle glaucoma?
Prostaglandin eye drops eg latanoprost 50mcg/ML / travoplost
Laser trabeculopasty
Surgical trabeculectomy
What is a cataract?
Any opacity in the lens
Leading cause of blindness
How common are cataracts?
75% of >65yr
20% of 45-65yr
Occur earlier in DM
What should be investigated when a cataract is found?
Fasting plasma glucose
Steroid use
High myopia - nearsightedness
Dystrophia myotonica