• cerebral venous thrombosis
• intracranial hypertension
• visual acuity
• magnetic resonance venography
• papilloedema

A 7.5-year-old previously healthy boy presented with progressively persisting headaches and acute blindness. Ophthalmologic examination disclosed visual acuity of 1/10, diminished colour vision and bilateral florid papilloedema. MR venography showed acute cerebral venous sinus thrombosis (CVST), (figure 1) and MRI showed signs of intracranial and optic nerve sheath hypertension without brain parenchymal anomalies (figure 2). Intracranial pressure (ICP) was measured at 23 mm Hg (normal value <15 mm Hg). Thrombophilic workup revealed homozygosity for the mutation C677T for methylenetetrahydrofolate reductase, a controversially discussed candidate genetic risk factor for hypercoagulability.1 The patient was put on …