BackgroundThere are many systemic illnesses that constitute risk factors for cerebral vein thrombosis (CVT). Hypothyroidism was never associated with CVT, despite growing evidence supporting a possible etiopathogenic link. We report two patients with CVT in whom hypothyroidism was concomitantly diagnosed.Clinical casesCases were women 21 and 52 years old. They both presented with intracranial hypertension syndrome and symptomatic focal epilepsy. CVT was diagnosed with MRI and MR venography. Hypothyroidism was diagnosed in the acute phase of CVT. Both had an autoimmune thyroiditis. None of the patients had diffuse goitre. Other risk factors for CVT were oral contraceptives and elevated homocysteine in one and hormonal replacement therapy in the other. Both were treated with anticoagulation, anti-epileptic drugs and thyroid replacement therapy, with good clinical outcome.ConclusionsThe 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.