Sixth cranial nerve palsy

52 Sixth cranial nerve palsy



Instruction


Examine this patient’s eyes.



Salient features



History




• Diplopia in all directions of gaze except away from the affected side


• Patient may rotate the head towards the weak side to produce a single image


• Patient may intentionally close the affected eye to prevent diplopia (pseudo ptosis)


• Hearing loss (acoustic neuroma)


• Diabetes or hypertension.



Examination




• The eye is deviated medially and there is failure of lateral movement.


• The diplopia is maximal when looking towards the affected side. The two images are parallel and separated in the horizontal plane. The outer image comes from the affected eye and disappears when the eye is covered.


• Proceed by telling the examiner that you would like to check the following:


• Blood pressure and urine sugar

• Hearing and corneal sensation (early signs of acoustic neuroma).


Diagnosis


This patient has a sixth nerve palsy (lesion) caused by diabetes mellitus (aetiology) and is having severe diplopia (functional status).



Questions




What are the causes of sixth nerve palsy?




• Hypertension


• Diabetes


• Raised intracranial pressure (false localizing signs)


• Multiple sclerosis


• Basal meningitis


• Encephalitis


• Acoustic neuroma, nasopharyngeal carcinoma


• Lyme disease (N Engl J Med 2007;356:1561).

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Dec 4, 2016 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Sixth cranial nerve palsy

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