Cranial Nerve Palsy

Description

Loss or reduction of function of the nerves that arise from the brain-stem. Relevant to the eye are the third, fourth, and sixth nerves which supply the muscles that move the eyes; the fifth nerve which supplies sensation to the eye and face; and the seventh nerve that supplies the muscles that move the face.

Loss of function may be due to problems at any point from their origin in the brain to their destination. These include loss of blood supply from eg diabetes or hypertension, pressure from masses in the brain eg tumour or aneurysm, stroke, trauma, infection eg shingles.

Clinical Features

Loss of function may be confined to one nerve or a combination of several depending on underlying cause
Third (oculomotor): Double vision, ptosis, enlarged pupil. May be pain around the eye
Fourth (trochlea): Double vision, usually vertical or oblique
Sixth (abducens): Horizontal double vision
Fifth (trigeminal): Loss of sensation on face. May be prior rash of shingles
Seventh (facial): Loss of power usually on one side to the face causing failure of eye closure, dribbling, poor speech

Management

See ophthalmologist for double vision or ptosis, urgently if sudden onset
Ophthalmic referral for facial weakness with incomplete eye closure, urgently if eye red, painful or reduced vision

Referral to neurologist often indicated

Images

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