Sudden hearing loss can be due to a number of causes. Some are simple physical problems such as impacted wax, or to middle ear effusions, easily diagnosed and treated. Others are due to more complex inner ear problems, or rarely to central pathology such as a vestibular schwannoma (acoustic neuroma). The first key to management is to identify whether the loss is conductive, in which case specialist opinion may not be required in many cases, or sensorineural, in which case urgent testing and medical treatment may be indicated.
Common Symptoms
- A unilateral drop in hearing is more common, but losses can occur in both ears in some cases
- Unilateral tinnitus can occur no matter what the cause
- A blocked feeling in the affected ear
- A greater than average sense of distortion with sound in the affected ear suggests a sensorineural cause
- Hyperacusis (extra sensitivity to sounds in the environment) in the affected ear suggests a sensory (cochlear) cause
- Associated balance disturbance or frank vertigo suggests a sensorineural cause
What are the causes of a sudden hearing loss?
Sudden Conductive loss:
- Wax impaction
- Foreign bodies
- Otitis externa
- Otitis media with effusion/ acute otitis media
- Barotrauma to the middle ear
Sudden Sensorineural loss:
- Viral infection
- Vascular problems affecting the cochlear blood supply
- Perilymph Fistula. In these cases the SSHL is usually linked to an episode of barotrauma such as after a SCUBA dive
- Endolymphatic Hydrops (fluid imbalance within the inner ear)
- Head injury or acoustic trauma
- Vestibular Schwannoma (Acoustic neuroma). Although only a small percentage of people with a SSHL have an acoustic neuroma, 15% of acoustic neuromas present this way.
What types of treatment will my patient have if a sudden sensorineural hearing loss is identified?
There is a lot of controversy as to the role and effectiveness of the medical treatment for sudden hearing loss.
Management may include:
- A course of oral Prednisone
- Oral vasodilators such as Pentoxyfylline (Trental)
- If endolymphatic hydrops is suspected, salt restriction, oral diuretics and perhaps oral Betahistine
- MRI scan to exclude a Vestibular Schwannoma
- If the hearing loss does not resolve, and if it is causing significant hearing difficulties, hearing aids may be recommended
What can I do if I suspect one of my patients has a sudden hearing loss?
It is important to determine whether the loss is conductive or sensorineural, because it is believed that the natural history of sudden sensorineural hearing loss can only be influenced in the first few days.
Examination of the ear canal and drum may demonstrate the reason for a conductive loss. Tuning fork tests should confirm your suspicions. A Weber test lateralising to the affected ear suggests a conductive loss and to the opposite ear a sensorineural loss. A negative Rinne test (BC>AC) in the affected ear suggests a conductive loss and a positive Rinne (AC>BC) a sensorineural loss.
If your examination and tuning fork tests suggest a sensorineural loss, we would recommend referral for an urgent audiogram within 2 days and if indicated, an ENT opinion. When calling audiology for an appointment say that you suspect a sudden sensorineural hearing loss. Even if clinics at Dilworth Audiology are already fully-booked, the patient will be seen urgently for testing.
The Audiologists at Dilworth Audiology have an excellent working relationship with the Otolaryngologists who consult on site, and will be able to arrange appropriate specialist follow-up when indicated. If in doubt, please don't hesitate to call for advice. Dilworth Audiology would like to thank Dr Robert Gunn for his additions to this document.
