This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Cranial nerve I palsy

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

A change in smell sensation due to a olfactory nerve palsy can be uni- or bilateral in nature. Lesions are most likely to cause anosmia and a bilateral lesion is more likely to be detected by routine enquiries about an individual's sense of smell.

Most causes of anosmia are bilateral.

Causes of bilateral anosmia include:

  • upper respiratory tract infection - most common
  • ethmoid tumour
  • meningioma of the olfactory groove
  • trauma, e.g. basal skull fracture, frontal fracture, after pituitary surgery
  • congenital, e.g. Kallman's syndrome
  • conductive, e.g. nasal polyps, enlarged turbinates

Causes of unilateral anosmia include:

  • head trauma without a fracture
  • early meningioma of the olfactory groove

Related pages

Create an account to add page annotations

Add information to this page that would be handy to have on hand during a consultation, such as a web address or phone number. This information will always be displayed when you visit this page