General Medical Information

Conductive Olfactory Loss

Richard L. Doty
Daniel A. Deems

In cases of conductive olfactory loss, where the anosmia or hyposmia is caused by airway obstruction, treatment to relieve the edema or physical obstruction can be undertaken with optimism. Pre- and postintervention olfactory testing is needed to establish intervention efficacy and to screen for subsequent slow relapse, so characteristic of most conductive disorders. Examples of treatments that have restored olfactory function include allergy management, topical and systemic corticosteroid therapies, antibiotic therapy, and various surgical interventions, including functional endoscopic sinus surgery. A brief course of systemic steroid therapy is often useful in distinguishing between conductive and sensorineural olfactory loss, as patients with the former will often respond positively to the treatment, although longer term systemic steroid therapy is not advised. Topical nasal steroids are ineffectual, in some patients, in returning smell function because the steroid fails to reach the affected regions in the upper nasal passages. Having the patient administer the spray or drops while in the Moffett position (i.e., with the head upside down, as when hanging the head over the side of the bed in the morning while in the supine position) can increase efficacy in some of these cases.

Although, as noted earlier in this chapter, rigid nasal endoscopy is very useful in diagnosing anosmia secondary to nasal pathology, the decision to perform endoscopy cannot be based solely on patient complaint, because approximately a third of patients with positive endoscopies deny frank nasal obstruction. Also, a negative endoscopic examination does not rule out an obstructive etiology. Thus, fine-cut coronal CT is frequently warranted in patients with conductive olfactory loss for both diagnosis and operative planning.