Endotoxin in middle ear effusions tested with Limulus assay.

Endotoxin in middle ear effusion (MEE) from both children and adult patients with otitis media with effusion (OME) was assayed with the Limulus amoebocyte lysate test, in parallel with the detection of microorganisms. Whereas only 17% of MEE from adults, diluted 1:10 showed the presence of endotoxin, endotoxin was found in 69% of MEE from recent and recurrent cases in children, although microorganisms were isolated from only one-quarter of the samples. 83% of mucoid MEE from children contained endotoxin, compared with 41% of serous MEE. In older children, endotoxin was less frequently detected in accordance with the fact that the incidence of OME decreases with age. It is concluded that endotoxin may be one of the important factors in the pathogenesis of onset of, as well as in delayed recovery from OME in children.