Objectives/hypothesis: Otitis media with effusion is the most common cause of childhood deafness. Gastroesophageal reflux has been implicated in the disease pathogenesis; therefore, it is necessary to identify the presence or absence of gastric juice in the middle ear.
Study design: Middle ear effusions were collected from children undergoing myringotomy. If gastric reflux has occurred, effusions should contain pepsin protein.
Methods: Total pepsin/pepsinogen protein, fibrinogen, and albumin content of effusions were measured in enzyme-linked immunosorbent assays using antibodies to porcine pepsin, human albumin, and human fibrinogen. Proteolytic activity of each effusion was measured at pH 2. The pH of effusions was measured.
Results: Fifty-nine of 65 effusion samples gave a positive result with the antipepsin antibody, which also recognized pepsinogen. Pepsin/pepsinogen levels ranged from 0.8 to 213.9 microg/mL (serum reference levels, 49.8-86.6 ng/mL). All effusions contained albumin and fibrinogen with respective ranges of 1.77 to 95.75 and 0.30 to 2.30 mg/mL (serum reference levels, 35-45 and 2.2 to 4.6 mg/mL, respectively). Acidic protease activity occurred in 19 of 65 effusion samples. The pH of effusion samples was 7 to 9.
Conclusions: The majority of effusion samples contained pepsin/pepsinogen protein; only 29% were active. The pepsin level in effusion samples based on activity is substantially lower than levels based on antibody detection; however, the pH present would irreversibly inhibit pepsin, which would explain the low levels of active enzyme. Pepsin/pepsinogen levels in the effusion samples were up to 1000 times higher than serum levels, whereas albumin and fibrinogen levels were of the same magnitude. The pepsin in middle ear effusions is almost certainly due to reflux of gastric contents, and there may be a role for antireflux therapy in the treatment of otitis media with effusion.