Unilateral Papilledema in Cerebral Venous Sinus Thrombosis.

In the majority of patients with raised intracranial pressure, the papilledema is bilateral. Unilateral papilledema is rare in conditions causing intracranial hypertension, and it has been described in Foster-Kennedy syndrome and in some cases of idiopathic intracranial hypertension. It has never been reported in cerebral venous thrombosis. We report a young lady presenting with features of subacute onset of headache with seizures, on evaluation she had superior sagittal and bilateral lateral sinus thrombosis. The risk factors found on evaluation were Vitamin B12 deficiency and hyperhomocysteinemia. On optic fundus examination, she had swollen optic disc on the right side with normal fundus on the left side, confirmed with the orbital ultrasound B-scan and optic coherence tomography. Her magnetic resonance imaging showed features of raised intracranial pressure with thrombosis of the superior sagittal and bilateral lateral sinus thrombosis. She was treated with anticoagulation (heparin followed by oral anticoagulants), antiedema measures, and vitamin supplementation for hyperhomocysteinemia. She improved over time and was asymptomatic during follow-up. We discuss the possible mechanisms described in the literature for unilateral papilledema. This report highlights the need for carefully performing bilateral fundus examination so as not to miss the vision or life-threatening causes of a headache.