ABSTRACT
BACKGROUND: Zinc is an essential mineral. Beneficial zinc absorption takes place via enteral, parenteral, or cutaneous routes. However, direct application to the olfactory epithelium has been reported to cause loss of smell. Recently, intranasal zinc gluconate has been recommended as a treatment for the common cold. Severe posttreatment hyposmia and anosmia have been observed. METHODS: The case report of a typical patient is presented and analyzed in detail, followed by a series of patients with severe hyposmia or anosmia after the use of intranasal zinc gluconate. RESULTS: Although interindividual variation in drug response and drug effect is apparent, the severe hyposmia or anosmia appears to be long lasting or permanent in some cases. The mechanism of olfactory loss is thought to be the direct action of the divalent zinc ion on the olfactory receptor cell. CONCLUSIONS: Zinc ions are toxic to olfactory epithelium. Reports of severe hyposmia with parosmia or anosmia have occurred after intranasal use of zinc gluconate.
Subject(s)
Olfaction Disorders/chemically induced , Zinc/administration & dosage , Administration, Intranasal , Common Cold/drug therapy , Gluconates/administration & dosage , Humans , Male , Middle AgedABSTRACT
The feigning of sensory loss (malingering) poses a challenge for psychophysicists. To uncover malingerers by means of psychophysical testing, we combined measures of response-sequence randomness with the maximum-likelihood adaptive-staircase procedure used to measure sensory detection thresholds. The two-alternative, forced-choice maximum-likelihood adaptive-staircase procedure calculates an estimate of the threshold after each trial and also recommends the stimulus concentration for the next trial. Olfactory detection thresholds for butyl alcohol were measured in 7 normals, 6 anosmics, and 6 malingerers. Each participant was tested for 20 trials. A discriminant analysis, using threshold concentration and probability of being correct over the 20 trials, could correctly classify only 68% of the malingerers and anosmics. Correct classification of anosmics and malingerers rose to 100% when statistical measures of randomness in the response sequences were included in the discriminant analysis. We conclude that the maximum-likelihood adaptive-staircase procedure, combined with response-sequence analysis, is a powerful addition to the arsenal of techniques for detecting malingerers in the evaluation of sensory ability.