CLINICAL AND ELECTRON-MICROSCOPIC STUDY F OR EVALUATION OF TREATMENT OF SUDDEN HEARING-LOSS WITH THE COMBINATION 10-PERCENT HES 200 0.5 ANDPENTOXIFYLLIN/

The incidence of sudden hearing loss has increased. The pathogenetic m echanisms are still unknown, but viral infections and vascular phenome na with acute impairment of microvascular perfusion are thought to pla y a major role. Infusion of hydroxyethyl starch (HES) is used as a reg imen to treat sudden hearing loss. In our clinic, anaphylactic reactio ns due to HES have not been observed so far. However, the use of HES i s still discussed controversially due to long-term storage of HES mole cules in tissue and due to high incidence of long-lasting pruritus. In a retrospective analysis of 118 patients treated with HES for sudden hearing loss, we observed pruritus starting in 64% of patients one to three weeks after therapy. This symptom with a duration between two we eks and four months was refractory to medical interventions. During th erapy with HES improvement of hearing was observed in 75% of patients, in 62% improvement of hearing persisted still at the end of the obser vation period (7 months post infusionem). Light and electron microscop ic assessment of human skin biopsies of one patient after treatment wi th HES showed storage of HES especially within dermal macrophages. Pat hogenetically a pathway independent of histamin seems responsible for the induction of pruritus. Accordingly, classic antihistaminic drugs h ad no therapeutic effect in our patients. Dextran is used as an altern ative to hydroxyethyl starch. In contrast to HES, the often mentioned higher incidence of severe anaphylactic reactions due to dextran has d ramatically decreased with hapten inhibition (after preinjection of mo novalent haptendextran Promit(R)). Therefore, dextran is considered th e best alternative to HES for therapy of sudden hearing loss.