Sudden hearing loss affects primarily middle-aged people and develops as a rule unilaterally in the course of one to three days.
Indications: Suspicion of autoimmune cause of sudden hearing loss.
Sudden hearing loss affects primarily middle-aged people and develops as a rule unilaterally in the course of one to three days. Autoimmune inner ear disease is regarded as a subgroup, where cortisone has positive effects. In these patients the hearing loss as a rule becomes bilateral after some time. Indirect immunofl uorescence on bone tissue from the ear has been used to fi nd out if an autoimmune process is involved. In 1990 Harris et al. reported that 35% of patients with progressive neurogenic hearing loss had a serum antibody against cochlea. In a patient material with unexplained progressive hearing loss there was a 1/3 chance that an immunological etiology was behind the hearing loss. In a study with 279 patients with idiopathic bilateral hearing loss 32% had antibodies that were observed with western blotting. There have also been reports that antibodies against the 68kD band were detected in the very patients whose condition improved with immunosuppressive treatment.
89% of the patients with an active bilateral neurogenic hearing loss had antibodies against the 68kD antigen but patients whose disease was inactive were negative. 75% of the positive patients responded to steroid treatment, whereas only 18% of the negative patients responded to the treatment. In a report it was shown that the 68kD band is heat shock protein 70 or a protein associated with it. Therefore HSP-70 is either the target antigen of the immune defence, shares epitopes with the real antigen or anti- SP 70 is an epiphenomenon that arises as a result of inner ear damage. Whatever the cause may be, the presence of this antibody in patients with progressive hearing loss is a tool for diagnosing an immune-mediated hearing loss and predicts steroid sensitivity. A large number of the patients have antibodies against the collagen-like part of C1q. Sudden hearing loss may also occur as a part of system diseases, such as Wegener’s granulomatosis, antiphospholipid syndrome or SLE.