Cerebral venous thrombosis (CVT) is a rare stroke that is caused by a blood clot in a vein in the brain. Diagnosis may be made by "swollen optic disks", due to progressive swelling. The first and most common symptom may be a severe focal headache that mimics a migraine. The "pulsating pain" is most often felt in one side of the head, often in the neck area, but sometimes it can occur on both sides. In addition, the headache is often accompanied by other symptoms such as nausea, partial paralysis, loss of consciousness or difficulty speaking.
There has been very little study of this condition, but at the beginning of the 21st century a large multi-centre study of CVT was being conducted in several countries.
Persons with a history of clotting problems, such as a condition called deep venous thrombosis, in which painful blood clots form in the legs, have a greater risk of CVT.