反復性中耳炎の成因について

Abstract

Recurrent acute otitis media (rAOM) is one of the most common pediatric diseases. Klein reported that the criteria for rAOM are three or more documented episodes of AOM in 6 months or four episodes in 12 months. Freijd A et al have reported subtle immunologic defects, i. e., IgG2 subclass deficiency in rAOM. The pathogenesis of rAOM, however, is still poorly understood.We examined 136 patients with rAOM aged 1 to 20 years who were attending our ENT clinic in Hokkaido. There was a higher incidence of rAOM in the younger children. Males had significantly more episodes than did females.To clarify the pathogenesis of rAOM, both secretory IgA and surfactant were analyzed in the present study. Secretory IgA is related to decreased bacterial adherence. Surfactant is composed mainly of phospholipid, i. e., DSPC (disaturated phosphatidylcholine), and has the definite function of lowering surface tension. Middle ear effusion samples were obtained from patients with OME (otitis media with effusion). OME patients with four or more episodes of AOM during a 12-month period were defined as the (rAOM +OME) group, and OME patients without a previous episode of AOM were in the OME group.Both secretory IgA and DSPC levels were lower in the (rAOM+OME) group than in the OME group. These results suggest that both immunologic disturbance and eustachian tube dysfunction play important roles in the pathogenesis of rAOM.