Sudden Sensorineural Hearing Loss
Red flags
Make sure that you are dealing with a sudden sensorineural hearing loss (SSNHL). There must be no history of head trauma, recent ear surgery or any signs of systemic illness eg meningitis. These symptoms would point you to another diagnosis such as temporal bone fracture or post-operative vestibulocochlear failure.
Why is this important?
Hearing loss can be debilitating and may affect patients with pre-existing chronic hearing loss.
When to involve the ENT registrar
During working hours if you need a specialist opinion.
Who to admit
Most UK ENT departments would not admit patients with SSNHL.
Assessment and Recognition
The aetiology of SSNHL is not clear. It is also known as idiopathic sensorineural hearing loss. Possibilities include i) atheromatous blockage of the vestibulocochlear blood supply; ii) viral neuronitis and iii) autoimmune disease.
A small minority of patients will have a vestibular schwannoma, also known as acoustic neuroma. Note that these benign masses are very rare with an incidence of 1:100,000 per year (an 'average' GP practice serves a population of 6000-8000 people) and that many schwannomas do not require intervention.
Patients will present with a history of sudden hearing loss. It is almost always unilateral. Many seem to go to bed fine and wake up with deafness. There may be associated tinnitus or vertigo but there should not be any significant otalgia, discharge or neurological signs eg nystagmus.
This usually prompts them to seek medical help urgently. Occasionally, patients with pre-existing hearing loss may not notice until a family member notices worsening deafness or that the television volume is turned further up.
Take a full history and perform a full examination of the ears, including otoscopy, facial nerve examination and balance tests; it is prudent to document general neurological findings ie GCS, eye movements, mobility etc.
If you are seeing the patient during working hours and have access to audiological services, this is an audiological emergency so ask whether they can perform an urgent audiogram for SSNHL
If not, perform bedside hearing tests and document the results clearly; make arrangements for the patient to re-attend for an urgent audiogram during the next working day
Audiological diagnostic criteria for SSNHL (the rule of three):
sensorineural loss with thresholds worse than 30dB;
in three consecutive frequencies;
onset within three days (72 hours).
Immediate and overnight management
Higher-quality evidence for the treatment of SSNHL is contradictory in many cases, including for oral steroid (see Cochrane Review reference below), however the following represents common practice in the UK:
ORAL STEROID: Prescribe oral steroid eg 60mg prednisolone reducing over ten days; if you prescribe steroid, you should consider gastric protection (evidence for benefit from oral steroid is mixed)
OTHER TREATMENTS: Few units have a policy of prescribing anti-virals eg aciclovir for five days (no evidence for benefit); There is some evidence that patients benefit from hyperbaric oxygen therapy but this is not available to most ENT units; There is no good evidence for the use of vasodilators such as carbogen
IMAGING: Request an MRI IAMs (internal auditory meati) as a routine outpatient
The patient should be assessed in the next available ENT clinic with Audiology support. Please note that many emergency clinics will not have access to Audiology so please liaise with the ENT team first.
Here is the ENT UK guideline on management of suspected SSNHL.
Recruitment for the STARFISH trial is ongoing
See https://entintegrate.co.uk/starfish for more details!
Further management
For many patients, hearing will recover spontaneously: studies suggest that around two-thirds will recover. The presence of vertigo may be a poor prognostic sign.
Patients whose hearing does not improve within 1-3 weeks may benefit from salvage intra-tympanic steroid injections.
For those with persistent hearing loss, hearing aids may be an option if the loss is not profound. Hearing therapy (available through many Audiology departments) can also help people to deal with hearing loss and tinnitus.
References
Page last reviewed: 21 April 2020