The association found between untreated hypothyroidism and CVT in these patients may result from chance. However, several haemostatic and fibrinolytic parameters have been demonstrated to be disturbed in hypothyroidism suggesting a possible role of this disease in CVT pathogenesis. In addition, indirect evidence also supports possible endothelial dysfunction and venous stasis in hypothyroidism, further emphasizing the physiopathological link between the two conditions. More research is needed to determine a possible causal role of hypothyroidism on CVT. We suggest that thyroid function should be included in the usual workup of CVT patients.