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