Sudden sensorineural hearing loss may vary from mild to severe (deafness) and usually affects only one side (unilateral). This type of hearing loss occurs over a short period, within a few hours or sometimes almost instantaneously. In most cases of sudden loss of hearing, the condition may spontaneously resolve with a partial or complete return of the hearing. In cases where the hearing loss resolves, it usually occurs within 10 to 14 days.
Causes of Sudden Hearing Loss on One Side
Causes of sudden hearing loss (SHL) are similar to the causes of tinnitus and should be investigated thoroughly. SHL can affect both adults and children.
Sudden hearing loss (SHL) is suspected to be caused by severe trauma to the ear, head or a cardiovascular accident (CVA or stroke) due to the rapid onset and one sided nature of the loss. However, most cases of sudden hearing loss occurs as a result of infections, especially viral infections.
Many childhood diseases and common viral infections can lead to sudden hearing loss. Viral endolymphatic labyrinthitis may occur as a result of these viral infections, which is the most common cause of sudden loss affecting only one ear. Known viruses/viral infections which may cause sudden hearing loss include :
Other conditions known for causing sudden hearing loss include neoplasms, lupus, Cogan’s syndrome, multiple sclerosis, Buerger’s disease and ototoxic drugs.
A perilymph fistula (an abnormally formed passage that develops due to pathological causes) may develop between the middle and inner ear and cause sudden hearing loss. Perilymph fistulas may occur as a result of sudden, severe pressure changes and certain strenuous activities like weight lifting.
Signs & Symptoms Associated with Sudden Loss of Hearing
Apart from the partial or complete loss of hearing or impaired hearing, other signs and symptoms may occur in conjunction with the condition, giving a possible indication of the cause.
- Vertigo – Meniere’s disease, middle or inner ear infections, cardiovascular disorders, stroke, perilymph fistula.
- Tinnitus (ringing sound in the ears) – Refer to the causes of tinnitus.
- Fever is usually indicative of an infection.
- Nystagmus (abnormal and rapid movement of the eyes from side to side) may indicate a perilymph fistula, head or ear trauma.
Treatment for Sudden Hearing Loss
Treatment should be directed at the cause if identified. In cases of viral induced inflammation or SHL of unknown causes, oral corticosteroids is among the most effective treatment. Local hydrocortisone applications within the ear may also assist with relieving the hearing loss. Anti-virals may be considered in prolonged viral infections suspected as a possible cause of SHL.
- Sudden Hearing Loss. American Hearing Research Foundation
- Sudden Sensorineural Hearing Loss. Baylor College of Medicine
- Sudden Deafness. Merck