Expert Commentary
In recent years, the introduction of new diagnostic techniques has made possible a considerable improvement in the management of CVT; however, some gray areas and uncertain aspects still exist and will probably offer the possibility of future progress. The main points concern the etiologic factors, the clinical indicators for an early diagnosis, the imaging techniques and the close relation and interdependence between therapy and prognosis.
In the field of etiology, many important conclusions have been reached, but some discrepancies between the various studies are evident. In particular, the importance of OCs, although relevant in all studies, varies considerably in relation to both methodological issues and the composition of the population considered. With respect to causative factors, the populations considered cannot be compared as they differ from a demographic and cultural point of view; in particular, some cultures reject OC for birth control. This observation highlights the importance of culture and ethnicity in the design and interpretation of epidemiological studies and clinical trials, a factor often overlooked and not considered fully. It should be considered that a large portion of CVT takes place in African and Asian countries, where obstetric causes are responsible for up to 30% of the incidence. The relevance of cultural factors will probably increase in the near future as a consequence of the rapid demographic changes induced by migration flows. The second consequence of the important role of OC and of pregnancy-puerperium as causative factors is that it fully qualifies CVT as a gender-related neurological disorder.
With respect to the clinical features, a clear distinction between presenting symptoms and symptoms developing along the course of the disease should always be made. The signs and symptoms of CVT are highly variable and often change in relation to the stage of the disease. Analysis of the scientific literature demonstrates a paucity of studies that specifically assess the clinical presentation and temporal evolution of symptoms. Headache has been clearly identified as the most frequent presenting symptom, but so far no specific features have been identified. Since headache is one of the most frequent conditions observed in the emergency setting, the identification of patients with CVT and headache as an isolated symptom is a challenging task. New case-control studies specifically designed to assess the problems of the clinical presentation and of the differential diagnosis of CVT, with a special attention for headache are, therefore, urgently needed.
New imaging techniques have considerably eased the diagnosis of CVT; the current gold standard is MRI of the brain with venous MRI angiography. However, these techniques still have a low sensitivity in the case of isolated thrombosis of a cortical vein or of early sinus thrombosis; in these instances conventional angiography is needed. The choice of the most appropriate and accurate examination must be based on the clinical features: this consideration again highlights the necessity of reliable clinical indicators for an early diagnosis, which may also guide the radiological diagnostic work-up.
The best available therapy for CVT is currently early anticoagulation with heparin. Although no clear differences between unfractioned and low-molecular-weight heparin have been demonstrated, we prefer unfractioned heparin because of the easier reversal of anticoagulation in case of hemorrhagic complications. An interesting alternative in the acute setting is offered by local thrombolysis, but its use is currently not supported by scientific evidence and should be considered as experimental. This treatment, however, could be considered in patients who worsen despite anticoagulation and who are comatose at presentation; the presence of intracerebral hemorrhage should raise more caution as it is probably linked with an increased risk of bleeding. Anticoagulation or thrombolysis should be attempted as soon as possible, as both trials and clinical experience have shown the importance of early treatment in improving the course of the disease. In fact, any delay in the diagnosis and treatment of CVT can have dramatic clinical consequences: venous thrombosis is a time-dependent process whose progress may be stopped by anticoagulants.
Overall, the best clinical management of CVT depends on the optimization of three main steps: the identifications of clinical indicators that give rise to a diagnostic hypothesis in the early stage of the disease, the choice of the best radiologic exams to support this suspicion and the early institution of the appropriate treatment.
Expert Rev Neurother. 2009;9(4):553-564. © 2009 Expert Reviews Ltd
Cite this: Cerebral Venous Thrombosis - Medscape - Apr 01, 2009.
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