aetiology

Last reviewed 07/2021

The aetiology of oculomotor nerve palsy is very diverse:

In adults:

  • central lesions:
    • tumours:
      • due to direct invasion of the third nerve nucleus
      • due to raised intracranial pressure
    • vascular:
    • caused by a brainstem lesion
    • demyelination

  • peripheral causes include:
    • compressive lesions:
      • tumour
      • aneurysm, often the posterior communicating artery
      • basal meningitis
      • nasopharyngeal carcinoma
      • orbital lesions e.g. Tolosa-Hunt syndrome
    • infarction:
    • often spares the pupillary reflex, when the condition is termed a "medical third nerve palsy"
      • often caused by diabetes mellitus

In children, the causes of a III nerve palsy include:

  • congenital
  • trauma
  • tumour
  • migraine