Any prothrombotic event acquired or genetic is considered a risk factor for cerebral venous sinus thrombosis.

Cerebral venous sinus thrombosis is more common in particular situations. 85% of patients have at least one of these risk factors:^[1]

• Thrombophilia (a tendency to develop blood clots due to abnormalities in coagulation, e.g. deficiency of protein C, protein S, antithrombin or related problems)
• Nephrotic syndrome (a kidney problem causing protein loss in the urine)
• Chronic inflammatory diseases (inflammatory bowel disease, lupus, Behçet’s disease)
• Pregnancy and puerperium (the period after giving birth)
• Particular blood disorders, especially polycythemia vera and paroxysmal nocturnal hemoglobinuria
• Use of the contraceptive pill
• Meningitis and infections of the ear, nose and throat area (mastoiditis, sinusitis)
• Direct injury to the venous sinuses, and medical procedures in the area

Other less well understood situations that increase the risk for cerebral sinus thrombosis are hyperthyroidism^[2] and myelodysplastic syndrome.^[3]