Abducens nerve palsy

Abducens nerve palsy, or sixth nerve palsy, 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 (e.g. idiopathic intracranial hypertension, obstructive hydrocephalus,.. )

  • 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

• intracavernous internal carotid artery aneurysm

See also

• oculomotor nerve palsy

• trochlear nerve palsy