ABSTRACT

In cases of anosmia from head injury or viral infections, the olfactory slits look normal on nasal endoscopy and on imaging, the damage being in the neurons themselves. These fail to be stimulated, and, therefore, fail to transmit the information to the brain for the perception of smell to occur. Scarring and adhesions from intranasal surgery have also been noted to cause anosmia or hyposmia. Neoplasms may also block the olfactory slit. They may invade from adjacent areas, or are intrinsic, as is the case with esthesioneuroblastomas.