Acute inflammation of the inner ear, which contains the cochlea and the organ of balance. The cause can be viral or bacterial. Possible viral causes are the influenza or mumps virus. Bacterial inflammation, usually resulting from an acute otitis media (inflammation of the middle ear), is much more serious. Viral inflammation of the inner ear, sometimes after influenza or mumps but sometimes in an otherwise healthy patient, leads to sudden deafness, often associated with ringing in the ears. Generally symptoms are limited to one side. Sometimes the organ of balance is more affected, causing giddiness, nausea and vomiting. There is no treatment for viral inflammation, and only general measures such as bed rest and medication for giddiness are of any use. The giddiness will pass, but hearing is not usually restored. With bacterial inflammation symptoms are much more severe: sudden total deafness with loud ringing in the ears (tinnitus), violent dizziness with nausea, vomiting and heavy perspiration. Meningitis is a possible complication.