Saturday, 23 November 2013

Sudden Hearing Loss

Please note that the following is a general guideline only. For a full assessment, exclusion of any other underlying cause for your symptoms and an individualised treatment approach, you will need to be seen by a qualified specialist.




Definition 
Sudden hearing loss is when hearing loss occurring in 3 days or less

Epidemiology
This affects 5-20 per 100,000 people. 
Highest incidence at 50-60yrs, median age 40-54 yrs.
Men and Women are equally affected

Cause?

Known causes only  25% of cases, 75% unknown ( Bit like high blood pressure-most of the time no one know what causes it) 



1) Infections 

Viral infections, Meningitis, rare other infections


2 Autoimmune Conditions
Some localised to inner ear, other generalised conditions like arthritis. 

3 Menier's Disease

4 Tumours (rare)
Inner ear nerve or brain tumours

5 Mini stroke and its risk factors

6 Injury
Physical: Blast injury, surgical
Chemical: some medications



Unknown: Theories
Viral inflammation? Not noticed by the patient !
Mini Stroke: with no other affects to the body !


Taking a History

When a patients presents complaining of a blocked ear its important to differentiate between blockage (sound not getting through) and loss of hearing.

Early identification of true hearing loss enables early treatment, this is when it is most useful.

Your specialist will also ask about sinister features? I.e.  associated neurology, visual loss, symptoms suggestive of an autoimmune condition.
Also it will be checked it fits with any of the known causes above


Physical Examination

Frequently unrevealing

Ear Inspection
Tuning fork testing-to differentiate between a loss and a block
Nerve exam
Stigmata of systemic disease


Natural History

High spontaneous recovery rate (1/3 up to  2/3 – majority in fist 7-14 days)
45% complete
70% >30dB improvement

Poor prognostic indicators
age > 40y or child
profound hearing loss >90dB
high frequency loss (i.e. down-sloping or flat patterns worse than up-sloping)

Investigations

Audio: at commencement of treatment and at the end
Blood work up: FBC, UE, TFT, Autoimmune screen, VDRL and others as per history
MRI: if significant asymmetrical hearing loss


Acute treatment

1 Steroids
High dose prednisolone 1 mg/kg 10 days
Check audio 2 weeks

2 HBO (Hyperbaric oxygen)
Emerging studies show that this helps if started during the first 4 weeks of hearing loss

3 Rest
About 10 days






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