The inflammatory response of the sinus and nasal mucosa during sinusitis: implications for research and therapy.

Since it is difficult to evaluate the state of an infected sinus mucosa by histopathology, much of the present knowledge of the morphology in sinusitis is based on animal experiments. When experimental sinusitis is induced in the rabbit, the inflammatory response in the nose appears to be more pronounced than that in the maxillary sinus. In the animal model, histological findings include epithelial desquamation, edema, goblet cell hyperplasia and, in severe cases, fibrosis, bone reaction and formation of polyps in the nose and in the antrum. These local pathological findings may persist in the nasal middle meatus and the paranasal sinuses for a considerable time and predispose the mucosa to recurrences of infection. By investigation with recently introduced advanced techniques such as magnetic resonance imaging (MRI), a protracted pathological state in the sinus mucosa can be recorded also in humans for months after an episode of acute sinusitis. Future human and experimental studies of the local inflammatory response and of the cellular pathology over time will yield further guidelines for improved therapy and prevention of acute sinusitis.