Lactate dehydrogenase as a measure of inflammation in experimental otitis media.

A reliable animal model for acute otitis media due to Streptococcus pneumoniae was used to study the accumulation of lactate dehydrogenase (LDH) in middle ear effusion during acute pneumococcal otitis media and after penicillin treatment. The findings indicate that LDH levels rise in the middle ear effusion during the early phase of acute infection and decrease as the infection resolves over time. Penicillin treatment affects the natural course of infection by resolving most visible signs of inflammation and by sterilizing the middle ear. However, once middle ear infection was established, penicillin treatment did not reduce the elevated levels of effusion LDH, suggesting that inflammation persists after sterilization of infected middle ears.