Intracranial venous thrombosis
Venous thrombosis of either cerebral cortical veins or dural venous sinuses, which may result in focal signs.
Causes include trauma, dehydration and sepsis, infection of adjacent foci in the head (e.g. middle ear or skull air sinuses) and it has been associated with thrombophillia, oral contraceptives, pregnancy and puerperium.
Impairment of venous drainage due to thrombosis may lead to venous infarction as tissue congestion may compromise the arterial blood supply. The high pressure in small vessels may cause rupture and haemorrhage.
Fever and headache are often features.
Cortical vein thrombosis results in a stroke and seizures.
Cavernous sinus thrombosis causes headache, fever and eye signs (diplopia, proptosis, chemosis, opthalmoplegia, papilloedema) which usually become bilateral.
Lateral venous sinus thrombosis has a sub acute on-set of fever, earache, headache, nausea and vomiting. Papilloedema may be seen. This condition arises from mastoiditis and is now rare.
Sagittal sinus thrombosis causes headache, papilloedema, focal signs, confusion and epilepsy.
CT head may show occluded veins, oedema or haemorrhage but is often normal, the best investigation is MRI with venography (MRV). Investigations to identify underlying causes should also be performed.
Anti-coagulation (despite evidence of haemorrhage), anti-convulsant drugs and treat the underlying cause wherever possible.