The evaluation and management of olfactory disorder following upper respiratory tract infection.

Abstract

Of the 5 senses, the sense of smell is the most neglected. The perception of smell is an integral and critical component of a person’s life. This is true, of course, unless it is altered or absent. The loss of the olfactory sense leads to an impaired quality of life as well as certain safety issues involving smoke and gas odor perception. Hyposmia and anosmia may be caused by a variety of factors. Prior nasal surgery, nonobstructive or obstructive nasal and sinus disease (ie, inhalant allergy, chronic sinusitis, nasal polyposis), dementia, Alzheimer disease, and normal aging may affect olfaction. Nasal septal deviation has not proven to be associated with anosmia. Clinically significant diminutions in olfactory sensitivity are present in more than 23% of patients who have allergic rhinitis. Histologically, the olfactory mucosa has proven essentially normal in those patients with nasal and sinus disease. Prior URTI is implicated in 14% to 26% of all presenting cases of hyposmia or anosmia. Other medical conditions as well as many drugs may cause a disordered sense of smell and are described elsewhere. Environmental pollutants can also have an effect on the olfactory system. Tumors such as olfactory groove meningiomas, frontal lobe gliomas, suprasellar pituitary tumors, and esthesioneuroblastomas are very rare causes of anosmia. The list of causes of sudden anosmia is quite short. Traumatic anosmia probably results from a shearing injury to the olfactory nerves. Postviral anosmia is the second most common type. Of 1834 patients who presented to 3 major centers of taste and smell disorders (the Connecticut Chemosensory Clinical Research Center, Farmington, Conn; the State University of New York Clinical Olfactory Research Center, Syracuse, NY; and the University of Pennsylvania Smell and Taste Center, Philadelphia), 349 (19%) had smell dysfunction related to a URTI. Only 36% of these patients had anosmia on testing. Standardized smell testing is used to demonstrate anosmia. The University of Pennsylvania Smell Identification Test is a 40-item, 4-alternative, forced-choice identification test using microencapsulated odors and is commercially available. Other forms of testing are also available. Neuroradiographic imaging serves to rule out abnormalities of the central nervous system. When indicated, magnetic resonance imaging (MRI) is the radiologic study of choice in the workup of anosmia. Subfrontal petechial hemorrhage can be detected on T1weighted imaging in the subacute and chronic periods following trauma. An MRI can also detect tumors of the olfactory system, nose, and paranasal sinuses. Congenital From the Division of Otolaryngology–Head and Neck Surgery, University of Kentucky Chandler Medical Center, Lexington. Sanford M. Archer, MD CLINICAL CHALLENGES IN OTOLARYNGOLOGY