4 months old boy | 2 years ago
How does acute otitis media cause disease?
2 years ago
Pneumococcus, Haemophilus, and Moraxella commonly reside in the back of the nose, and do not infect the child. Once a child becomes infected with a respiratory virus, it not only causes congestion of the nose and the lungs, but also of the eustachian tube. When this tube becomes clogged, the cells in the middle ear space produce a fluid-like substance, which allows bacteria to grow and infect the middle ear space. A virus infection precedes up to 90% of cases of acute otitis media. Respiratory virus infections also trigger ear infections by upsetting the body's normal defenses in the nose and the eustachian tube, and allowing certain normal bacteria that reside in the nose to "stick" better to the lining of the nose and the eustachian tube. Certain viruses, such as the flu (influenza) and RSV (a respiratory syncytial virus, or the "bronchiolitis bug"), are more frequently associated with ear infections. Occasionally, the child's nose becomes colonized by a new aggressive strain of bacteria, which rapidly invades the middle ear. Unfortunately, more exposures (e.g., via daycare attendance) to viruses and new strains of bacteria increase the likelihood of ear infections.