Third Nerve Palsy
Third nerve palsy, whether complete ( involving
both the intrinsic muscles of the eye together
with the extraocular muscles ) or
incomplete ( affecting only the extraocular
muscles ) has different
outcomes.
1. Complete recovery may occur soon in a week or
two. Rapid recovery suggests neurapraxia, without axonal
loss.
2.
In diabetics or hypertensive patients, the
pathology is vascular where nerve infarctions
occur and recovery does not begin for a month or more but is
usually complete within 3 months . This suggests a
lesion of axons, with preservation of nerve
connective tissue.
3.
With aneurysmal compression or
trauma, it can take up to 2 or 3 years to recover
completely, suggesting more severe anatomic
disruption of the nerve. If ptosis following trauma
is going to recover completely, it usually does so
within 6 months but occasionally takes as long as 2
years
4.
In some cases of third nerve palsy, the
paralysis persists completely unchanged. These
nerves have usually been transected by trauma or
chronic compression or have been infiltrated by
tumor.
5. Sometimes recovery is only partial. This
occurs especially after damage to the fascicular
portion of the nerve. Partial recovery may be
characterized by oculomotor nerve synkinesis,
so-called aberrant regeneration. Usually this
synkinesis becomes apparent within 9 weeks after
injury, but it has taken 3 to 6 months
This 62 years old diabetic patient has complete third
nerve palsy 15 days ago , most probably of
vascular origin , no history of trauma ,
normal fundus with bilateral normal optic nerve head. I usually ask for brain MRI
in acquired cranial nerve palsy to rule out
compressive lesions.
|
.jpg)
