Otitis media is generally caused by Haemophilus influenzae and Morakota catarrhalis, while the pathogenesis of exudative otitis media is still unclear. In recent years, the role of endotoxin in the pathogenesis of otitis media has attracted great attention. Many researchers have determined the endotoxin in the middle ear exudate (MEE) of patients with otitis media. Bernstein et al. found that 7% of sterile middle ear exudates contained endotoxin, 67% of culture-negative middle ear exudates contained endotoxin, and the positive rate of endotoxin in mucous middle ear exudates was higher than that in serous middle ear exudates.

Many experiments have shown that the submucosal connective tissue of the middle ear is thickened, the cell density is increased, and the capillary permeability is enhanced in the experimental animals attacked by endotoxin. The destruction of capillaries and the leakage of serum may be the main causes of otitis media caused by experimental endotoxin. Nonomura et al. recently proposed based on the histological observation that in addition to serum leakage, endotoxin also destroyed the normal mucociliary transport system.

It has been reported that after the onset of otitis media, the incidence of sensorineural deafness and tympanic membrane separation is very high. Whether bacterial antigens or toxins can pass through the round window membrane and damage the inner ear is uncertain. The animal experiments of Lin Jizhen and others showed that endotoxin can cause changes in the function and structure of the cochlear nerve, suggesting that endotoxin may penetrate the round window membrane into the inner ear, causing the sequelae of otitis media. It is also reported that the endotoxin of Escherichia coli causes ototoxicity damage to blood vessels, seriously disrupts the water and ion metabolism of the cochlea, and leads to energy failure of the inner ear, which may be an important factor for otitis media complicated with cold deafness. Lin Yuanjing et al. carried out a smear examination, bacterial culture, and Limulus test on the middle ear effusion of 86 adult patients with secretory otitis media. The results showed that the presence of bacteria and endotoxin in the middle ear cavity of secretory otitis media was one of the important reasons for the occurrence of middle ear effusion or the delay of the effusion.

To sum up, endotoxin plays a very important role in the pathogenesis of otitis media. Therefore, comprehensive treatment should be comprehensively considered in the clinical treatment process. If anti-endotoxin therapy is applied timely, it can not only shorten the course of the disease but also reduce the occurrence of complications, which will be a major breakthrough in the medical field.