Thrombophilias | Genetic – eg Factor V Leiden |
| Acquired – eg antiphospholipid syndrome |
Infection | Intracranial |
| Regional eg ear, nose, throat, head, neck |
| Systemic |
Trauma | Head injury |
| Cranial surgery |
| Lumbar puncture |
| Endovascular intervention |
Reproductive | Pregnancy |
| Puerperium |
Malignancy | Intracranial |
| Extracranial |
Medications | Oral contraceptives |
| Steroids |
| Anti-neoplastic drugs (particularly L-asparaginase) |
Inflammatory | Vasculitis eg Behçet’s disease |
| Systemic lupus erythematosus |
| Inflammatory bowel disease |
| Sarcoidosis |
Haematological | Iron deficiency anaemia |
| Polycythaemia |
Endocrine | Hyperthyroidism |
Systemic | Dehydration |
| Sepsis |
Intracranial abnormalities | Dural fistulaeVenous anomalies |
| Arteriovenous malformations |