Abducens nerve palsy

Abducens nerve palsies, or sixth nerve palsies, results in weakness of the ipsilateral lateral rectus muscle.

Clinical presentation

Patients present with horizontal diplopia with an inability to abduct the ipsilateral eye, thereby resulting in an esotropia (nasal deviation of the eye).

Pathology

The abducens nerve has the longest subarachnoid course of all the cranial nerves.

Etiology

• increased intracranial pressure
  • results in downward displacement of the brainstem, causing stretching of the sixth nerve secondary to its location within Dorello's canal
• microvascular (e.g. diabetes mellitus)
• subarachnoid space pathology (e.g. subarachnoid hemorrhage, meningitis, neurosarcoidosis, neoplasm)
• cavernous sinus pathology (e.g. cavernous sinus thrombosis)
• pontine pathology (e.g. stroke, neoplasm, multiple sclerosis)
• trauma

See also

• oculomotor nerve palsy
• trochlear nerve palsy