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
