Disorders Flashcards
What is Etiology?
The cause, or set of causes, of a disease or condition.
What are the general causes of hearing loss (8)?
Trauma (4) force noise barotrauma iatrogenic
Infections - viral bacterial fungal
Genetic/hereditary
Ototoxicity
Metabolic
What is Iatrogenic?
Injury inadvertently caused a a result of medical treatment ie perforated ear drum due to wax syringing
What is the formal name for the infections of the outer, middle and inner ear?
Otitis externa
Otitis media
Labrynthitis
Define ototoxicity.
Ability of certain drugs to damage the hearing system ie side effects of essential medication
Define metabolic
Relating to, or deriving from, the metabolism of a living organism
OR
Something that just happens ie excessive wax
What type of loss do we get with outer, middle and inner ear?
Outer conductive loss
Middle conductive
Inner sensori neural loss
What is the golden rule for outer ear disorders?
COAT
CONDITION explain it, what caused it, permanent or temporary, congenital or acquired?
OTOSCOPY what can you see, what does patient report?
AUDIOMETERY type and degree of loss. Sudden or gradual onset?
TREATMENT includes hearing aids
What is otitis externa?
An infection of the outer ear:
Infective: bacterial, viral or fungal
Reactive: eczema, psoriasis or dermatitis
Symptoms and treatment for a bacterial infection of the outer ear (Otitis externa)
Symptoms: swelling, redness possible pus
Treatments: antibiotic’s, steroids, acidic ear drops
Symptoms treatment for viral infection of outer ear
Herpes zoster (shingles) Ramsay Hunter syndrome
SYMPTOMS pain, rash, blisters
TREATMENT analgesics tropical lotions antiviral therapy beneficial within 72hrs of onset
3-5 weeks to clear
Symptoms treatment of fungal infections of the outer ear
Symptoms itchy more than painful, dry skin, inflammation
TREATMENT anti fungal cream
Otomycosis
What type of HL is associated with cochlea disorders?
Sensorineural - results in patient struggling with such discrimination (I can hear but they mumble - lack of consonants)
What is frequency resolution?
Ability of the ear to differentiate between sounds of SIMILAR frequencies which produces sharper hearing.
When hair cells become damaged frequency resolution becomes less efficient add CLARITY is reduced.
What is temporal resolution?
Ability of brain to ID very small gaps in sound which is very important to speech discrimination.
Stops speech becoming one long SLUR
With cochlea damage this ability is lost.
What is loudness recruitment?
When hearing threshold is reduced and sound increases above this level, the perceived rate of growth of loudness is greater than normal.
When sound becomes sufficiently high, loudness growth returns to normal.
Recruitment results from damaged sensory cells of cochlea. They then recruit neighbouring cells to hear the frequency.
Explain the upward spread of masking effect.
It is the ability of low frequency sounds to mask out high frequency sounds.
Low freq moves entire BM, if high freq introduced at same time, BM part for that freq has already moved tectorial membrane soo low freq has lessened intensity perceived by cochlea of that high frequency.
What is Presbyacusis?
Age related hearing loss. The most common general cause of HL resulting in slow, progressive, bilateral SN loss mainly of high frequencies (door mat effect)
Often:
Bilateral
Symmetrical - to same degree
Sloping
Sensori neural
Genetic element
Affects approx 50% of those 75+ years
What are the 4 different etiologies of presbyacusis?
SENSORY: hair cell degenerate within organ of corti. Mainly at basal end, door mat effect.
NEURAL: degeneration of ganglion cells, reduction in synapses (junctions) loss of nerve cells that transmit impulses along auditory pathway. Comes into play when 90% of individual cell damaged.
METABOLIC: degeneration of Stria vascularis capillaries - affects chemical composition of endolymph
MECHANICAL: thickening and stiffening of BM reducing elasticity.Most severe at basal end as already more taut.
Risk factors of Presbyacusis?
Thrombosis/heart conditions
Ototoxicity
Diabetes
Noise
What are the symptoms of Presbyacusis?
Speech unclear - people mumble
High pitched sounds difficult to hear or tell apart.
Difficulty with conversation in BGN
Can’t hear consonants
Certain sounds annoying or overly loud
Tinnitus May also occur
What is the treatment Presbyacusis?
Hearing aids with good aural rehabilitation.
Aids must:
Work/change quickly (temporal)
Amplify - quiet Sounds more
Loud sounds less
High freq more
Low freq less
And not over amplify low freq to prevent upward spread of masking.
What is the cochlea dead region?
Where the HL is so severe the inner hair cells and neurons completely lose their function.
Amplification of high frequency dead region will not improve speech intelligibility.
What is Ménière’s disease - what are the 4 descriptors?
Over production of endolymph in the cochlea.
Idiopathic: unknown cause
Episodic: episodes/attacks
Endolymphatic: endolymph related
Hydrops: excessive pressure
Endolymphatic sad becomes swollen with excess fluid
Greatest effect at apical end therefore affects low frequency loss
Membrane May bulge pushing Scala media into Scala vestibuli/tympani
What are the 3 distinct stages of menieres?
State 1: disabling vertigo with nausea/vomiting. Preceded by aural fullness/pressure. 20 mins - several hours. Low frequency HL
Stage 2: HL becomes more established. But still fluctuates, often UNILATERAL at this stage. SN loss, low frequency - reverse slope. Vertigo attacks in clusters then subside having reached a maximum. Tinnitus more noticeable.
Stage 3: HL main symptom. More severe and permanent. Vertigo diminishes. 50% develop BILATERAL loss.
What are the treatments for Menieres?
It is not curable to date there we treat the symptoms.
MEDICATION:travel sickness pills
Diuretics to stop water retention/fluid build up
Steroids - gentamycin albeit can damage hearing!
Anti-inflammatory injection via TM
VESTIBULAR rehabilitation: head, eyes, neck exercises
DIET: low salt diet to reduce water retention
SURGERY:
endolymphatic shunt - drainage
Endo sac decompression - removal of surrounding bone to allow sac expansion
Vestibular nerve section severed
Labyrinthectomy - destroy labyrinth results in total HL!
What are the drug groups which can cause Ototoxicity in the inner ear? What are the effects?
Antibiotics ie gentamycin
Anti cancer
Anti malaria ie quinine
NSAIDS non steroid anti inflammatory
Diuretics
All can affect the chemical composition of endolymph
1st symptom often high pitched tinnitus
Bilateral high frequency SN loss
Severity depends on dosage/duration
Usually sudden
Temporary or permanent
What are the inner ear viral infections?
Cytomegalovirus: congenital
Rubella: reisseners membrane
Measles: mixed loss
Mumps: unilateral and severe
Herpes Zoster (shingles) cochlea and retro cochlea lots
Mostly acquired
Temporary or permanent
Mostly bilateral
High frequency loss
Can lead to vertigo
What are the bacterial infections of the inner ear?
Labyrinthitis: from otitis media
Bacterial meningitis - from IAM
Syphilis
Acquired
Temporary or permanent
Mostly bilateral
High frequency HL
can lead to vertigo
What are the inner ear disorders in addition to Presbyacusis and Ménière’s disease?
DIPLACUSIS: same sound gives different pitch to each ear. Usually with asymmetrical loss.
HYPERACUSIS: over sensitive to any sound, intolerance to normal sounds. Reduced ULL’s .
OTOTOXICITY, INFECTIONS viral and bacterial. Other causes:
TRAUMA
NEOPLASIA - tumours
OTOSCLEROSIS - if passes through round window
PAGETS DISEASE
IATROGENIC
HEREDITARY/GENETIC
