Nasal Polyposis As a Cause/Correlate of Anosmia

    In June of 2005 I discussed with otorhinolaryngologist, Paul Camnitz, the mechanisms by which nasal polyps can cause anosmia.  When I asked if polyps in the sinuses in the absence of polyps in the nose could cause anosmia by interfering with the flow of scented air to the olfactory mucosa, he said no.  Polyps in the nose can cause anosmia by preventing the flow of scented air to the olfactory mucosa high in the nasal cavity.  When scented air reaches the olfactory mucosa, receptors there initiate neural signals which are carried through tiny olfactory neural fibers through the cribriform plate into the brain.  When the brain receives these signals, we experience the sensation of scent.

    I asked Dr. Camnitz if polyps can form high in the nasal cavity, and if he goes up that high in the nasal cavity when he does sinus surgery.  He told me yes, they can, and yes, he goes all the way up next to the cribriform plate when doing sinus surgery.  In other words, he not only investigates and removes polyps from the sinuses, but also from the nasal cavity, and it is the polyps in the nasal cavity (and/or other obstructions there) that can prevent scented air from reaching the olfactory mucosa.

    I also asked Dr. Camnitz if inflammation in tissues near the cribriform plate could produce anosmia by compressing the olfactory neural fibers there.  He said yes, it could.  He added that polyposis and inflammation of other tissues up there tend to go together -- if you have the one problem, you are likely to have the other problem too.  If the inflammation is very bad and prolonged, it can cause permanent damage to the olfactory system, such that later remission of the inflammation will not be accompanied by restoration of the sense of smell.  Dr. Camnitz noted that steroids both shrink nasal polyps and reduce inflammation of other tissue up there, and thus can help restore the sense of smell for those whose anosmia is caused by either of these conditions (nasal polyps and inflammation).

    This discussion with Dr. Camnitz has helped me understand how sinus surgery can fail to restore one's sense of smell.  Even after the polyps are removed, if inflammation is compressing the olfactory fibers and/or preventing the flow of scented air to the olfactory mucosa, the person may remain anosmic, at least after the steroids (often given before, during, and/or after sinus surgery) wear off.  Of course, a person could have polyps, inflammation, and yet another problem (such as damaged receptors in the olfactory mucosa) causing anosmia, in which case removal of the polyps and reduction of the inflammation would not be sufficient to restore the sense of smell.


Contact Information for the Webmaster,
Dr. Karl L. Wuensch

This page most recently revised on 15-February-2020.