Differentials Cranial Nerve Palsy

Question 1

CN3 Oculomotor

Answer 1

“Down and out, ptosis, dilated pupil”

• Vascular
• Tumour
• Demyelination
• Compression - orbital lesion
• Infarction from diabetes

Question 2

CN4 Trochlear

Answer 2

Eye up and out / head tilted away from affected side

Question 3

CN6 Abducens

Answer 3

Failure of abduction of eye

• Vascular
• Tumour
• Demyelination
• Bilateral = Mobius syndrome
• Duane syndrome

Question 4

CN5 Trigeminal

Answer 4

Issues with sensation 3 branches, corneal reflex, wasting jaw

Vascular, tumour, demyelination
Posterior fossa tumour
Meningitis
Acoutic neuroma, meningioma 
Cavernous sinus pathology

Question 5

CN7 Facial

Answer 5

Cannot raise eyebrows, puff out cheek, smile

• Bell’s palsy
• Ramsay Hunt syndrome
• Oititis media
• Tumour
• Vascular
• Acoustic neuroma/meningioma

Bilateral facial weakness

• Myasthenia
• GBS
• Bilateral parotid disease

Question 6

CN12 Hypoglossal

Answer 6

Issues with wasting, fasciculations, deviation tongue

Vacular
Tumour
Trauma
Meningitis/infective

Question 7

CN2 Optic

Answer 7

Visual difficulties

Glaucoma
Optic neuritis
Papilloedema secondary tumour, infection,