Central retinal vein occlusion with bilateral stenosis of the internal carotid arteries.

A 41-year-old lady presented to our clinic in July, 2014, with a 1-week history of sudden-onset painless loss of vision in her left eye accompanied by mild left frontal headache. She had previously been healthy and took no drugs. On examination the right eye was normal with best-corrected visual acuity (BCVA) of 20/20. BCVA was 20/200 in the left eye with a relative aff erent pupillary defect, prominent optic nerve swelling with optic disc haemorrhages, dilated and tortuous retinal vasculature, scattered fl ame haemorrhages throughout the periphery, and cotton wool spots along the vascular arcades (appendix). Fluorescein angiography was consistent with a central retinal vein occlusion complicated by cystoid macular oedema (fi gure). Vital signs were normal and she had no focal neurological signs. Blood tests showed microcytic anaemia caused by iron defi ciency (haemoglobin 79 g/L [normal 120–160 g/L]; mean corpuscular volume 70 fL [82–92 fL]), and thrombocytosis (platelets 597 × 10/L [150–400 × 10/L]) attributed to mild dehydration. Lipid profi le and serum glucose were within normal limits, as were systemic infl ammatory markers (erythrocyte sedimentation rate and C-reactive protein). Tests for Lyme disease and syphilis were negative. We also excluded acquired and congenital coagulopathies predisposing to a retinal vein occlusion: homocysteine concentrations were normal, anticardiolipin and antiphospholipid antibodies were absent; factor V Leiden, protein S, protein C, and prothrombin G20210A mutations were not detected. Because optic disc swelling was prominent, the visual loss was severe, and central retinal vein occlusion caused by optic disc swelling has been reported, we did MRI of the brain and orbits, which showed multiple loci of hyperintensity on T2 images in the right superior frontal cortex and in the anterior centrum semiovale white matter at the vertex, consistent with old vascular insults. CT angiogram and cerebral angiogram showed severe stenosis of the distal right intracranial carotid artery followed by complete occlusion of the communicating intracranial carotid artery with collaterals between the external carotid and intracranial vessels, resulting in enlarged lenticulostriate arteries that reconstituted more distal branches of the right middle cerebral artery (appendix, fi gure). The left intracranial carotid artery was severely stenotic distal to the ophthalmic segment with prominently enlarged lenticulostriate arteries, consistent with Suzuki Grade IV Moyamoya vessels. The left ophthalmic artery was prominent with collateral fl ow into the anterior cerebral artery distribution (fi gure). After neurosurgical consultation, the patient had uncomplicated superfi cial temporal artery–middle cerebral artery anastomosis on the left side. At last follow-up in December, 2014, fundus fi ndings had resolved and BCVA was 20/25 in the left eye. Moyamoya syndrome is a rare cerebrovascular occlusive disease (prevalence is 0·086 cases per 100 000 people in the USA) consisting of bilateral stenosis or occlusion of the intracranial carotid arteries resulting in irregular intracerebral anastomotic vessels. There is a bimodal distribution, with two thirds of cases occurring in children younger than 15 years and another peak in the fourth decade. Treatment aims to prevent ischaemic events and advanced cases might need direct surgical bypass of occluded vessels. Central retinal vein occlusion usually aff ects patients older than 50 years of age and is commonly associated with hypertension, diabetes, or glaucoma. For young patients, central retinal vein occlusion is occasionally associated with acquired or hereditary hypercoagulable states or systemic infl ammation, typically in patients with personal or family history of venous thromboembolism. If laboratory investigations for hypercoagulable states and systemic infl ammation are inconclusive, imaging studies for structural abnormalities of the carotid vasculature should be considered because decreased arterial fl ow can lead to venous stasis and thrombosis.