The etiology of sudden
sensorineural hearing loss is still unclear and is thought to result from disturbances of microcirculation, infectious causes, or autoimmune disorders. So far standard
therapy did not show clear improvement over spontaneous remission rate, which is assumed to be about 50% [Nakashima et al., Acta. Otolaryngol. Stockh. 514:14-16, 1994; Schuknecht and Donovan, Arch. Otorhinolaryngol. 243:1-15, 1986; Harris and Sharp,
Laryngoscope 100:516-524, 1990; Mayot et al., Clin. Immunol. Immunopath. 68:41-45, 1993; Gussen, Ann. Otol. Rhinol. Laryngol. 85:94-100, 1976]. Elevated blood viscosity due to high
fibrinogen levels is supposed to cause decreased cochlear blood flow and thus initiate
sudden hearing loss. The specific lowering of
fibrinogen immediately decreases plasma viscosity exactly to the desired extent and should lead to improved cochlear blood flow [Suckfüll et al., Acta. Otolaryngol 119:763-766, 1999; Suckfüll, Lancet 360:1811-1817, 2002; Walch et al., Laryngol. Rhino. Otol. 75:641-645, 1996; Suckfüll et al., Otol.
Neurotol. 23:309-311, 2002]. In a prospective uncontrolled pilot study on 36 patients with unilateral sudden onset
sensorineural hearing loss (SHL) we tried to establish that 1-3 specific
fibrinogen aphaereses alone improve recovery of hearing and that it is possible to lower
fibrinogen to the target of 80-100 mg/dl without important side effects. Pure tone audiometry was carried out immediately before and after each aphaeresis as well as at 2 and 4 weeks and 6 months
after treatment. Sixteen patients recovered spontaneously before undergoing
fibrinogen adsorption. All 20 aphaeresis patients improved during immunoadsorption; in 60% of patients auditory thresholds returned to normal after the first immunoadsorption and treatment could be discontinued, in another 20% of patients complete recovery was reached after 4 weeks. The mean plasma
fibrinogen concentration of the 20 patients before the first aphaeresis session was 308.1 +/- 51.5 mg/dl. Immediately after the first treatment session, the
fibrinogen concentration was lowered to 100.7 +/- 25.3 mg/dl (P < 0.001). The second and third sessions also showed highly significant reductions in plasma
fibrinogen. No important side effects were seen. In conclusion, specific
fibrinogen adsorption is a promising new treatment modality that should be tested in a prospective, randomized controlled trial in patients with
sudden hearing loss.