Sixth nerve palsy
Most cases of sixth nerve palsy seen in the examination has an obvious esotropia making the diagnosis easy.
However, in mild palsy the best way to demonstrate its presence is by cover/uncover test with distant fixation.
The affected eye has a convergent squint (this may not be obvious in mild or partially recovered sixth nerve
palsy). On cover/uncover test, the eye shows esotropia which is worse for distance than near. On ocular motility
testing, the affected eye has limited abduction. There is a A pattern esotropia on upgaze (this is because the
lateral rectus acts best as an abductor on elevation).
In the examination:
- there may be abnormal head posture with face turn to the affected side
- if asked for further examination mention that you would like to perform blood pressure check, urine
test for diabetes and fundal examination for papilloedema. If the patient wears hearing aid, consider
middle ear infection as a cause but this is now rarely seen (see question below).
1. Where about is the lesion located in a patient with a sixth nerve palsy plus the following features:
a. bilateral optic disc swellings