• Nalaka de Silva

Sudden Hearing Loss

Updated: Jun 16, 2019

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

Loss of 30dB or more over at least 3 consecutive frequencies occurring in 3 days or less



Epidemiology

Annual incidence of 5-20 per 100,000

Highest incidence at 50-60yrs, median age 40-54 yrs.

M=F



Aetiology

Known causes only 25% of cases. Some of these are



1) Infections

Viral infections

Granulomatous: i.e. syphilis, Mycoplasma, Lyme disease, toxoplasmosis

Bacterial Infections: Meningococcal meningitis


2 Autoimmune Conditions

localised to the inner ear

systemic

i.e. PAN, Cogan’s syndrome (with visual loss), SLE, RA, Wegener’s, Relapsing polychondritis, temporal arteritis, scleroderma, dermatomyositis, UC



3 Menier's Disease


4 Neoplasia

Acoustic neuroma and other IAC tumours


5 Vascular-Stroke and its risk factors


6 Traumatic

Physical: Blast injury, post-surgical, post-lumbar puncture

Chemical (ototoxicity)


7Central Deafness

Due to a underlying neurologic condition



Idiopathic Theories

Viral inflammation: direct viral damage vs immune response

Mini Stroke: cochleovestibular blood supply affected by microemboli. Anoxic injury as cochlear is end organ with no collateral supply.





Signs and Symptoms




When a patient presents complaining of a blocked ear, they may have developed sensory hearing loss. Its early identification enables early treatment when it is most useful.





Any sinister features? i.e. associated neurology, visual loss, symptoms suggestive of an autoimmune condition.

Does it fit with any of the known causes?


1) Viral Prodrome, picture suggestive of labyrinthitis? (severe vertigo and vomiting and hearing loss )

2) Any history is suggestive of an autoimmune condition. Ensure no associated visual loss (Cogan's syndrome gives hearing loss and uvitis)

3) Any risk of a granulomatous condition, recent overseas travel

4) Meniers' features: Recurrent vertigo lasting hours associated with temporary hearing loss, ear fullness and tinnitus.

5) Any likelihood of a neoplasm: other cranial nerves affected, other neurology/ headaches

6) Risk factors for micro embolism (both risk of atherosclerosis and other blood disorders as leukaemia, sickle cell disease etc)

7) Underlying neurologic condition

8) History of trauma, blast injury





Physical Examination

Frequently unrevealing


Otoscopy

Tuning fork testing- (A MUST IN ANY PATIENT COMPLAINING OF BLOCKED EARS)

Cranial 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 the commencement of treatment and at the end

Blood workup: 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

If no improvement, cease

If improvement, recheck audio after ceased - consider further steroids if hearing loss off steroids as it may be autoimmune related


2 HBO (Hyperbaric oxygen)

Emerging studies show that this helps if started during the first four weeks of hearing loss


3 Rest

About ten days







20 views1 comment

Recent Posts

See All