Transient third nerve palsy in a young patient with intracranial arteriovenous malformation

To describe a patient with transient third nerve palsy as the possible presenting sign of intracranial arteriovenous malformation. Case report. A 24-year-old female presented to ophthalmic casualty with sudden onset binocular diplopia and was diagnosed to have right sided partial third nerve palsy. Within 30 hours the third nerve palsy had recovered completely. A MRI scan and subsequent carotid angiogram revealed a large, high flow, trans-cortical Spetzler-Martin grade 4 arteriovenous malformation. The feeder vessel of the AVM originated from the right middle cerebral artery. Superficial venous drainage was via the superficial middle cerebral vein to the right transverse sinus. The deep venous drainage was via thalamostriate veins into markedly dilated internal cerebral vein and vein of Galen (Great cerebral vein). Venous reflux was noted around the midbrain from the vein of Galen. Transient third nerve palsy may rarely occur secondary to intracranial arteriovenous malformation. Ophthalmologists should consider neuroimaging in the investigations for transient cases of III nerve palsy in young patients.