THURSDAY, Feb. 3 (HealthDay News) -- A rare form of stroke that involves veins instead of arteries occurs more often than thought, according to a new American Heart Association/American Stroke Association scientific statement.
This type of stroke -- cerebral venous thrombosis (CVT) -- is caused by a clot in the dural venous sinuses, which are veins that drain blood from the brain toward the heart. It is most common in women who are pregnant or taking oral contraceptives, and in people age 45 and younger.
The incidence of CVT among pregnant women and those who have recently given birth ranges from one in 2,500 to one in 10,000. The risk is greatest during the third trimester of pregnancy and in the first four weeks after giving birth. Up to 73 percent of CVT cases occur immediately after childbirth.
But women who've suffered CVT have a low risk of complications during future pregnancies, according to the scientific statement.
Patients with suspected CVT should have blood tests to determine if they have an inherited or acquired factor in the blood that increases the risk of blood clots (prothrombotic factor).
In addition, patients should be screened for conditions that increase the risk of CVT, such as the use of oral contraceptives, inflammatory disease and infection.
"The most common symptoms of patients with CVT include headaches that progress in severity over days or weeks, and seizures. Some patients may develop a focal neurological deficit (weakness affecting the extremities, double vision, etc.)," Dr. Gustavo Saposnik, chair of the statement writing group and an assistant professor of medicine at Saint Michael's Hospital, University of Toronto, said in an American Heart Association news release.
Diagnosis of CVT can be challenging. For example, 30 percent to 40 percent of patients with CVT may develop an intracranial hemorrhage (bleeding within the skull).
"It's important to distinguis
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