Third Nerve Palsy

Question 1

Pathology / description

Answer 1

Palsy due to damage of the oculomotor nerve.
Third cranial nerve innervates EOMs, sphincter pupillae and levator palpabrae

Question 2

Differential diagnosis

Answer 2

• simple ptosis

• stroke

• horners syndrome

• myasthenia gravis

• other nerve palsies

• sudden onset diplopia

Question 3

Signs

Answer 3

• ptosis

• strabismus (down and out)

• mydriasis

• usually unilateral

Question 4

Symptoms

Answer 4

• sometimes none

• diplopia

• if pupil covered, reduced VA’s

• possible pain / severe headaches

Question 5

Pathogenesis

Answer 5

• oculomotor nerve palsy

• head injury

• trauma

• infection

• tumour

• aneurysm

• toxic reaction

Question 6

Investigations required by DO

Answer 6

• ask px if they experienced recent ocular pain / discomfort

• ask px if any sudden visual changes ie diplopia

• lift lit of RE to identify any pupil changes / strabismus

• if no ocular changes / symptoms, px can be treated as simple monocular ptosis

• DO should attempt to access clinical records to identify any record of monocular ptosis

• practitioner should make urgent referral to GP for onwards referral / management

• DO should consider a ptosis prop

Question 7

Management required

Answer 7

• urgent 48hrs if strabismus & ptosis

• emergency if pupil involvement and / or orbital / cranial pain