Headache in cerebral venous thrombosis.

In the past, cerebral venous thrombosis (CVT) was considered a rare, devastating disease. The widespread use of angiography, magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) over the years has made early diagnosis of CVT possible and has completely changed the perception of this condition. CVT is much more common than previously thought. It has a wide spectrum of clinical presentation, multiple causes and unpredictable outcome. In contrast to arterial stroke, headache is the most frequent and, at times, the only symptom of CVT. It is crucial to recognise the association of headache with CVT in order to reach a correct diagnosis and to start the appropriate treatment as soon as possible. Therefore in order to define the headache features useful for an early diagnosis of CVT we reviewed the current literature on this topic and performed both a retrospective and a prospective study. In the literature we found that this headache has no specific features as it can be of any grade of severity and is slightly more frequently diffuse than localised. Its onset is usually subacute over a few days but it can also be acute or chronic. It is mostly persistent but can occasionally be intermittent. Headache attributed to CVT is sometimes misleading, mimicking migraine, subarachnoid haemorrhage, CSF hypertension or hypotension. However this information has been derived from case series which lacked a control group and thus have low statistical strength. Our retrospective study, confirmed by preliminary results in the prospective multicentric study, showed that headache in CVT is as often acute as subacute, and that it is more frequently localised than diffuse. Finally, both studies showed a significant correlation between headache of acute onset and severe intensity and CVT. We then conclude that these headache features, especially in the presence of underlying prothrombotic conditions, should lead clinicians to consider the diagnosis of CVT and to require appropriate neuroimaging examinations.