Cerebral Venous Sinus ThrombosisCerebral venous sinus thrombosis is one of the serious causes of headache. Over 90% will report headache prior to diagnosis. It can usually cause two main types of headache:
Pregnancy is a risk factor for venous sinus thrombosis. Usually there are other clinical signs to indicate that this may be one of the more dangerous headaches. New onset seizures, or a stroke in a young person or woman on the oral contraceptive pill or who is pregnant should also raise this condition as a potential diagnosis. Other features may alert you that there is something more serious going on: These signs include:
Venous sinus thrombosis has a wide range of possible clinical presentations. At one end there is an isolated new onset headache which will resolve spontaneously. At the other is progressively raised intracranial pressure with cerebral infarction (stroke) which can be disabling or fatal. Cerebellar infarction is also described causing secondary hydrocephalus (that patient survived). Anatomy of the Venous Sinuses
The venous sinuses are the final drainage channels for blood from the head. In the brain, capillaries merge to form cortical veins. These veins then merge and flow into venous channels made by folds of dura mater. The main venous channel that runs along the middle, for the entire length of the brain is the superior saggital sinus. There is also an inferior saggital sinus. The other sinus that is commonly thrombosed is the transverse or lateral sinus. (Images courtesy of Bartleby.com: Creative Commons License). Superior saggital sinus thrombosis is more likely to be associated with stroke, but transverse or lateral sinus thrombosis is more likely to cause raised intracranial pressure. Diagnosis of Venous Sinus ThrombosisLike all headaches, some level of diagnostic suspicion is needed.If you are not considering CVST you are quite likely to not find it! A plain CT brain will only show changes in 20% of cases. Specific imaging - like CT Venography or MR Venography is necessary. The choice between CT and MR Venography will mostly be determined by local availability and local expertise. In our hospital we have better resolution on CT Venography, so it is the modality of choice for me. Most publications will recommend MR Venography - but you need to discuss the modalities with your radiologist. Properly performed CT venography and MR Venography will stand a high chance of correctly identifying cerebral venous sinus thrombosis. Thrombosis of a cortical vein (cortical vein thrombosis) may require formal catheter angiography for diagnosis. In any acute headache, if CT Brain is normal, then Lumbar Puncture should be performed, especially if thunderclap headache occurred. Suspected raised intracranial pressure also means that Lumbar Puncture is necessary (as long as CT Brain scan does not demonstrate an abnormality that contraindicates Lumbar Puncture - e.g. mass effect with lateral brain shift). The Cerebrospinal fluid in venous sinus thrombosis is often at high pressure (>20cm pressure) and has a slightly elevated protein concentration. Subarachnoid haemorrhage can be caused by venous sinus thrombosis, and most neurologists will have seen a case of CVST present with subarachnoid haemorrhage. Therefore bilirubin may be detected on cerebrospinal fluid analysis for xanthochromia (using spectrophotometry). In summary, to make a diagnosis you need
Treatment of Venous Sinus ThrombosisIt is accepted that anti-coagulation with intravenous unfractionated heparin or high dose subcutaneous low molecular weight heparin is necessary.This should be followed by at least 3 months of anti-coagulation, although I note that in one series the mean duration of warfarin (Coumadin) use was 9 months. I have recommended 6 months in my own cases. The recent reports of isolated venous sinus thrombosis causing headache without stroke or seizures had a good outcome. This suggests that the diagnosis can be missed without an adverse outcome for the patient, except that they had to endure persistent headaches without proper diagnosis! I suspect many people have presented for assessment of new onset headaches which resolved over several weeks. These people probably did have dural sinus thrombosis, such as the transverse sinus, but fortunately their problem resolved itself. However, a small number have a catastrophic outcome, and once seen is never forgotten (I have seen cases which were fatal, or resulted in stroke or subsequent epilepsy). I also know cases where there have been persistent headaches that are very difficult to treat satisfactorily. Overall the risk of recurrence is about 12% in one series of 154 people (20 had a recurrent thrombotic event). Aftercare Following Hospital DischargeUsually people with thrombotic disorders are diagnosed and cared for as in-patients. Follow-up after hospital discharge is necessary in order to:
ReferencesPreter M, et al. Long-term prognosis in CVST: follow-up of 77 patients. Stroke. 1996;27:243-246.(Free Full Text)Cantu & Barinagarrementeria. CVST associated with pregnancy and puerperium: review of 67 cases. Stroke. 1993;24:1880-1884.(Free Full Text) Kimber J. Cerebral Sinus Thrombosis QJM; 2002; 95: 137 - 142.(Free Full Text) Cumurciuc R et al JNNP 2005;76:1084-7. 17 cases presenting as isolated headache. Gosk-Bierska I et al. Cerebral venous sinus thrombosis: Incidence of venous thrombosis recurrence and survival. Neurology. 2006;67:814-9. Allroggen and Abbott Cerebral venous sinus thrombosisPostgrad Med J.2000; 76: 12-15 (Free Full text if you register) SFTM de Bruijn et al. Clinical features and prognostic factors of cerebral venous sinus thrombosis in a prospective series of 59 patients.J Neurol Neurosurg Psychiatry. 2001;70:105-8. (Free full text - pdf) G Georgiadis et al. Cerebral sinus thrombosis presenting with cluster-like headache. Cephalalgia 2006;27:79-82. (Free Abstract only) Stam J. Thrombosis of the Cerebral Veins and SinusesNEJM 2005;352:1791-8. (Free Abstract - you can find free copy via Google, but it may infringe copyright - I'm not sure if legal)
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