Somerville

An unusual cause for intermittent trochlear nerve palsy?

•       Otherwise healthy 35 y.o. male with several 3-5 day bouts of diplopia looking down and to right over the past 2 years.  Sx have spontaneously resolved each time.

•       Exam normal (pt. asymptomatic)

•       Routine blood work and myasthenia serology negative.

•       MRI/MRA demonstrates anomalous origin of a redundant left PCA from left supraclinoid ICA and typical left PCA arising from basilar tip.

•       Right, but not left trochlear nerve seen on hi resolution coronal MRI.

SUMMARY:  Images and clinical findings suggest possible vascular compression syndrome involving left IVth CN.

Submitted by Steve Somerville, MD  Green Bay, WI