Olfactory Disturbances — Pathophysiological findings and the development of new therapeutic procedures —

Chronic rhinosinusitis is the most frequent cause of hyposmia. We established a new experimental animal model to investigate pathological findings in the olfactory epithelium and olfactory bulb of rats and describe the possible etiology of hyposmia due to rhinosinusitis. Not only dysfunction of the olfactory epithelium but a central type of hyposmia caused by disorders of the olfactory bulb was demonstrated by immunohistochemistry. The possible etiology of hyposmia after common colds and dysosmia after traumatic olfactory disorders is also described based on recent studies. Hyposmia after common colds is strongly associated with nasal obstruction, swelling of the nasal mucosa, and edema of the mucosa of the olfactory cleft observed by nasal fiberscopy. Viral infection is considered one of the etiologies of anosmia after common colds, especially in women from 40 to 60 years old, and results in a poor outcome. One possible explanation of olfactory dysosmia is misdirected connections during reinnervation of the olfactory bulb by olfactory nerve fibers after apoptotic change of olfactory receptor neurons and traumatic amputations of olfactory filla at the level of ethmoid lamina cribrosa. These findings suggested new ideas for the treatment of patients with different types of olfactory disturbances.