Cerebral Venous Sinus Thrombosis Risk Factors in Young Women

Primary Risk Factors

Oral contraceptive use is the single most important modifiable risk factor for CVST in young women, with 85-96% of young female CVST patients using oral contraceptives, conferring a 13-22 fold increased risk 1, 2
The American Heart Association notes that oral contraceptives represent the dominant acquired risk factor, with meta-analyses showing a relative risk of 15.9 (95% CI 6.98-36.2) and odds ratio of 5.59 (95% CI 3.95-7.91) 1, 2
Pregnancy and puerperium account for a substantial proportion of cases, with an estimated 12 cases per 100,000 deliveries 3
Most pregnancy-related CVST occurs in the third trimester or postpartum period, with 7 of 8 pregnancy-related CVTs occurring postpartum 3
Risk increases with cesarean delivery, maternal age, hypertension, infections, and excessive vomiting in pregnancy 3, 4

Protein C deficiency carries a combined odds ratio of 11.1 for CVST 5, 6
Protein S deficiency and antithrombin III deficiency are significant risk factors, though antithrombin III deficiency is rare (only 2% in one series) 5
Factor V Leiden mutation and prothrombin G20210A mutation are important genetic thrombophilias 5, 6

The combination of oral contraceptives with inherited thrombophilia dramatically amplifies CVST risk beyond either factor alone, with Factor V Leiden + oral contraceptives: OR 30.0 (95% CI 3.4-263.0) and Prothrombin G20210A mutation + oral contraceptives: OR 79.3 (95% CI 10.0-629.4) 1, 2, 7

Cancer accounts for 7.4% of CVST cases, particularly hematologic malignancies 1, 2
Parameningeal infections (ear, sinus, mouth, face, neck) explain 8.2% of adult cases 1, 2
Paroxysmal nocturnal hemoglobinuria, iron deficiency anemia, thrombocythemia, systemic lupus erythematosus, Behçet disease, inflammatory bowel disease, nephrotic syndrome, and thrombotic thrombocytopenic purpura are rare hematologic and inflammatory conditions that may contribute to CVST 1, 2

When evaluating a young woman with suspected CVST, immediately assess oral contraceptive use, determine pregnancy/postpartum status, screen for inherited thrombophilias, evaluate for hyperhomocysteinemia, consider malignancy screening, and rule out parameningeal infections 1, 2, 3, 4, 6