Cranial nerve palsies

• LR6 = lateral rectus – abducens
• SO4 – superior oblique – trochlear
• 3 – all others – oculomotor nerve

6th nerve palsy

• Horizotnal binocluar diplopia – worsens with gaze towards affected side
• Causes – tumour, trauma, raised ICP, congenital, orbitoapthies, thyroid ey disease, myasthenia gravis, supranucela disorders
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Third cranial nerve palsy

 

 “down and out”

• pupil dilated – mydriasis
• eyelid droop – ptosis
• Causes
  • Intracranial aneurysm – potential SAH
  • Tumour
  • Trauma
  • Raised ICP
• Clinical
  • Sudden onset binocular diplopia
  • Droopy eyelid
  • Enlarged pupils – unreactive
  • Resting in down and out – abduction, slight depression, intorsion
  • Difficulty with – adduction, elevation, depression
• Consider what other neurological deficits are present

4^th cranial nerve palsy

• patient may have diplopia that is maximal when the eye looks downwards and inwards.
• An isolated fourth nerve palsy is unusual. 
• It may occasionally occur with lesions of the cerebral peduncle.
• clinical:
  • diplopia – particularly marked in reading
  • abnormal head posture – head tilted towards the normal side, face rotated towards the normal side, and the chin is depressed. The affected eye is higher than its fellow.
  • positive head tilt test – affected eye moves higher when the head is tilted towards the affected side