Guidelines for the treatment of cerebral venous thrombosis have been published by the European Stroke Organisation (ESO)/European Academy of Neurology (EAN) and the American Heart Association/American Stroke Association (1, 2), but there are few data available on treatment in Norway.
We fully concur with the international guidelines that patients with cerebral venous thrombosis should be treated in a stroke unit. Treatment must focus on anticoagulation therapy and symptom management with a view to preventing complications and death.
Although almost two-thirds of patients have venous haemorrhagic infarcts in the acute phase, anticoagulation with low molecular weight heparin is the recommended treatment for all patients, including pregnant women (dalteparin 100 IU/kg x 2 or enoxaparin 1 mg/kg x 2) (1). This recommendation is based on two small randomised controlled studies that showed a non-significant clinical difference between low molecular weight heparin and placebo, but equally importantly showed that heparin did not increase the risk of haemorrhage (15).
After initial anticoagulation therapy with low molecular weight heparin, a switch to a vitamin K antagonist (warfarin) is recommended over the course of a few days. A lack of randomised studies means that there is uncertainty regarding the optimal duration of warfarin treatment. An international multicentre study comparing 3–6 months of treatment versus 12 months is ongoing. Meanwhile, 3–6 months is recommended if a transient cause of cerebral venous thrombosis is identified (for example, pregnancy), and 6–12 months if there is no known precipitating factor (1). The aim of treatment is to achieve an INR value of 2.5 (1).
Lifelong anticoagulation treatment must be considered carefully in the event of recurrent cerebral venous thrombosis, known thrombophilia or multiple prothrombotic conditions. As current knowledge is lacking, we suggest following specific recommendations for the prevention of recurrent venous thromboembolic events in those conditions (1).
There are as yet no completed studies with the new direct-acting oral anticoagulants (DOACs), and only case reports are described in the literature (1). At least three DOAC studies are currently ongoing, with the results expected in 2018–20 (3).
There is no evidence to support systemic intravenous thrombolysis in cases of cerebral venous thrombosis (16). The available evidence is too weak to support the routine use of thrombectomy and other forms of endovascular treatment, such as stenting, but these may be used in individual cases where severe clinical deterioration occurs despite full medical treatment (1, 17).
Independently of treatment strategy, studies show partial or complete recanalisation in 50–90 % of patients (3). Recanalisation occurs gradually over time, and improvements may be seen on diagnostic imaging as late as 11 months after disease onset. The clinical significance of this is uncertain, as studies comparing degree of recanalisation with prognosis have yielded conflicting results, and have used different grading scales and classifications (3).
Increased intracranial pressure is common in the acute phase of cerebral venous thrombosis. Headache resulting from increased intracranial pressure may be treated with analgesics, whereas steroids and acetazolamide are no longer routinely recommended for intracranial pressure reduction owing to weak supporting evidence (1). Surgical decompression in the event of increased intracranial pressure and impending transtentorial cerebral herniation may be lifesaving in the acute phase (1, 18). About 15 % of patients develop obstructive hydrocephalus as a result of cerebral oedema, but ventriculoperitoneal shunting is not recommended as routine practice (1).
Patients who experience seizures should be treated with anti-epileptic drugs and those who experience seizures in the acute phase and/or parenchymal haemorrhage are at increased risk of further seizures (10). The optimal duration of treatment with anti-epileptic drugs is unknown. Previous guidelines advised treatment for one year, but this recommendation has been removed in the absence of definitive evidence to support it (3).
Visual field deficits in cases of cerebral venous thrombosis usually resolve and <10 % have persistently impaired vision (3).
There is no consensus regarding the follow-up of patients after cerebral venous thrombosis. In our experience, the need for and usefulness of follow-up appointments varies from patient to patient, but we believe there should be a clinical follow-up after three months. Further appointments must be tailored to the needs of the individual, but it is reasonable to continue with follow-up for as long as the patient is taking anticoagulants and/or anti-epileptic drugs.
The usefulness of MRI scans in the follow-up is unclear, and such scans rarely have consequences for treatment. However, we feel it is reasonable to consider MR venography after six months, primarily to obtain new MRI data following the acute episode, which can then serve as a new baseline should the patient experience new symptoms of cerebral venous thrombosis.