[Persistent isolated abducens nerve palsy from pontine infarction confirmed by gadolinium-DTPA enhanced MRI].

An 80-year-old man had left isolated abducens nerve palsy after repeated conjugate deviation to the right without any other findings. MRI demonstrated no abnormal lesion of T2-weighted images, while left paramedian tegmentum pontis was enhanced as responsible lesion by gadolinium (Gd)-DTPA on the 13th hospital day when Foville syndrome lasted. On the 33rd hospital day when isolated abducens nerve palsy lasted, however, this lesion was not detected with Gd enhanced images. The diagnosis of abducens nerve palsy caused by pontine infarction was obtained. Our patient had a lesion involving the left PPRF and ipsilateral abducens nerve. We concluded that the complete damage of left abducens motoneuron may cause isolated abducens nerve palsy lasting more than one year after Foville syndrome due to the dysfunction of left PPRF. To our knowledge, this is the first report of the persistent isolated abducens nerve palsy resulting from a pontine miniature ischemic lesion speculated by Gd enhanced MRI.