Diseases Of Inner Ear Flashcards
Sensorineural hearing loss
Sensorineural hearing loss
Lesions to the cochlea, 8th nerve or central auditory pathway prevent transmission of acoustic vibrations and frequency specific action potentials
Aetiology of SNHL
Congenital or Acquired Unilateral or bilateral
Common causes of unilateral SNHL
Sudden onset SNHL Menieres Vestibular schwannoma Trauma to temporal bone (fractures and head injury) Infections (bacteria. Viral, meningitis, labrynthitis) Iattogenic post OP deafness Acoustic trauma
Common causes of bilateral SNHL
Presbycusis Ototoxicity Familial progressive hearing loss Systemic disease (DM, SLE, hypothyroidism) All unilateral causes affecting both ears Autoimmune inner ear disease Noise induced occupational hearing loss
SNHL clinical fetaures
Hearing loss from birth or gradual. Onset may also be sudden. Difficulty hearing in noisy surroundings and where people are talking from different directions Speech and word discrimination difficult
SNHL rehab
Hearing aid
Presbycusis
Hearing loss condition associated with aging process
The type of hearing loss in SNHL
Bilaterally symmetrical
How to diagnose SNHL
Pure tone audiometry. Showing bilateral hearing loss. Reduction of both air and bone reduction. No air- bone gap
What do you need to rule out in a unilateral hearing loss
Vestibular schwannomas Cerebello Pontine angle tumours
Ototoxicity
The tendency of certain therapeutic agents to damage tissues of inner ear
Clinical features of ototoxicity
Tinnitus Hearing loss Disequilibrium
Tinnitus in SNHL
Initially high pitched, continuous then low pitched when damage continues. Early warning sign of inner ear damage
Hearing loss in SNHL
Often gradual but immediate with loop diuretics
Vertigo in SNHL
True vertigo is rare, as both ears are affected symmetrically
Where does disequilibrium predominantly occur
With vestibulotoxic drugs
Common ototoxic drugs
Aminoglycoside antibiotics Loop diuretics (furosemide) Salicylates (aspirin) Quinine Cisplatin and carboplatin Erythromycin Chloramphenicol Indomethacin Ibuprofen Propranolol Propylthiouracil
Noise induced hearing loss
Decline in hearing acuity due to noise exposure
Acoustic trauma
Single exposure to intense, loud sound from firecrackers, fire arms, blasts
Vertigo
False sense of motion, either of environment or of 8individual when there is nonen
Benign paroxysmal positional vertigo
Spinning sensation when head is placed in certain position
To confirm BPPV
Dix-Hallpike
BPPV aetiology
Free floating otoconial debris from the utricle or saccule settled in semicircular canal. Moves with endolymph pt itself moves causing vertigo
BPPV treatment
Epleys manouevre
Vestibular neuronitis
Sudden onset of severe vertigo which lasts for several days to weeks
Clinical features if vestibular neuronitis
Acutely unwell Pt lies still on bed Nausea and vomiting Vestibular Weakness
Vestibular neuronitis treatment
Vestibular sedatives Anxiolytics Vestibular rehabilitation therapy
Tinnitus
Perfection of sound in absence of any external source¹
Subjective tinnitus
Only heard by patient Ringing Buzzing Hissing Roaring
Otologic causes of tinnitus
Impacted cerumem, Otitis externa OME Otosclerosis Meniers disease Noise trauma Ototoxic drugs tumours of CN 8 Presbycusis
Non otologic causes of tinnitus
CNS: stroke, tumors, MS, epilepsy, migraine Anaemia Hypertension Hypoglycemia Metabolic disturbance
Objective tinnitus vascular causes
Aberrant internal carotid artery High and dehiscent jugular bulb Glomus tumours Arteriosclerosis AV malformations
Aetiology of tinnitus
Anything that reduces hearing By everyone when exposed to loud noise
Tinnitus investigations
Pure tone audiometry MRI CT NEURO evaluation
Most common cause of facial nerve paralysis
Bells palsy
Bells palsy
Most common CN neuro disorder. Cause of 60-65% of all facial nerve paralysis. Acute onset peripheral lower motor neuron facial nerve paralysis
Aetiology of Bell’s palsy
HSV that enters the lips and moves to geniculate region Reactivated in stress causing loss of myelin and temporary facial nerve paralysis Herpes Zoster (Ramsay Hunt syndrome)
Pathophysiology of Bells palsy
Vascular ischemia Inflammation and oedema of nerve Increased pressure in bony Fallopian canal and further ischemia Borrelia infection, autoimmune reaction, microvascular disease and inflammation
Bell’s palsy clinical features
Wekaness of sudden onset affecting upper and lower face unilaterally Flat forehead and nasolabial fold Inability to raise eyebrow Face deviates to normal side when smiling Poor eyelid closure Post auricular pain or ear may precede the weakness Epiphora Loud sound intolerance Nostalgia ocular pain Blurry vision Taste disturbance
How to grade facial wekaness of Bells palsy
House Brackmann grading system
Bell’s palsy treatment
Eye care Oral steroids Antivirals like acyclovir
Ramsay Hunt syndrome
Herpes Zoster infection resulting in facial nerve paralysis. 10-12% of facial paralysis
Herpes Zoster oticus clinical features
Burning pain in ear Vesicular rash Dizziness Tinnitus Hearing loss
Labrynthitis
Ingectice trauma or COM complicationaffects entire lanynth. Cayses6inflammaton sippration is irreversible
The triad of Menieres disease
episodic vertigo, fluctuating hearing loss and tinnitus,
What is often associated with the triad of Menieres
Aural fullness
Evaluation in Menieres disease
Clinical examination of the ear reveals no abnormalities.
Tuning fork tests will show the presence of sensori-neural hearing loss of a varying degree (positive Rinne’s test, Weber lateralising to the better ear).
Nystagmus can be appreciated during an acute attack
Diagnosis in Menieres
Pure tone audiometry reveals sensorineural hearing loss.
The characteristics of sensorineural hearing loss in Menieres
Early in the disease the hearing loss is more at lower frequencies with an up-sloping audiometric curve; however, as the disease progresses, hearing decreases further, whereby affecting all frequencies with the curve flattening out
Tumours of the inner ear
Acoustic neuroma
What is acoustic neuroma?
It is a benign tumour, arising from the Schwann cells of the vestibular nerve. Thus, it is also called the vestibular schwannoma. It affects individuals in the 4 th to 6th decades
Aetiology of acoutic neuroma
The only predisposing factor, which increases its incidence, is exposure to radiation. Bilateral acoustic neuromas are seen in patients with neurofibromatosis II.
Clinical features of acoustic neuroma
Unilateral hearing loss and tinnitus are very common presenting features
There is compress the VIIIth cranial nerve, producing hearing loss
Vertigo is not common as the tumour grows quite slowly,
As tumours grow larger, the trigeminal nerve can be affected, causing facial numbness
Paraesthesia and hypoaesthesia of the posterior meatal wall
Cerebellar signs
