• neuroophthalmology
• headache
• MRI
• MRA

A man in his late fifties had right-sided retro-orbital pain and diplopia for 1 month. There was no preceding head trauma. On examination, he had a right abducens palsy with subtle bilateral chemosis and proptosis, but no ocular bruit. The visual acuities were 6/9 on the right and 6/6 on the left whereas pupils, funduscopy, visual fields by confrontation, colour vision and intraocular pressures (right 15 mm Hg, left 20 mm Hg) were normal bilaterally. MR scan of brain (T2-weighted images) showed bilaterally abnormal flow voids in the cavernous sinuses, with enlargement of the cavernous sinuses, right superior ophthalmic vein and left spheno-parietal sinus (figure 1A,B). Follow-up MR imaging with time-of-flight MR cerebral angiography showed abnormal flow signals in these venous structures, indicating a carotid-cavernous fistula (figure 1D). Digital cerebral angiogram confirmed bilateral indirect carotid-cavernous fistulae (barrow type D, see below) with retrograde cortical venous reflux (figure 2), which were successfully treated with endovascular embolisation.