Aetiology

Primary, or aseptic, cerebral venous thrombosis is rare. It usually occurs in the very young, the very old, or the debilitated. Predisposing factors include:

• anaemia
• increased blood coagulability
• hypotension
• cachexia
• dehydration

Causes of secondary thrombosis include:

• most frequently, direct injury through a fracture of the skull or other trauma
• spread of infection from a neighbouring site:
  • cavernous sinus and sagittal sinus thrombosis - from infection of the face, or of the sphenoid, frontal or ethmoid sinuses
  • lateral sinus thrombosis from mastoiditis
  • furunculosis and cutaneous sepsis
• pregnancy, puerperium
• oral contraceptive pill
• dehydration
• haematological disease, for example polycythaemia
• malignancy - metastatic emboli
• miscellaneous, including polyarteritis nodosa