Cerebral venous thrombosis (CVT) is mostly caused by pro-thrombotic factors. Hyperthyroidism is not a wellknown risk factor. We present a case report on a 17 year old girl who developed life-threatening CVT after Graves’ disease. A review of the literature reveals further 34 cases of CVT and hyperthyroidism. Abnormalities in the coagulation system leading to hypercoagulability such as increased coagulation factors are detected in patients with hyperthyroidism, and these abnormalities seem to be thyroxin-dependent. The cause of CVT may be multi-factorial. Our patient used oral hormonal contraception without complications until the development of severe Graves’ disease. Hyperthyroidism is suspected as the main precipitating cause of CVT in this case. We recommend performing MRI with venous angiography when a hyperthyroid patient presents with unusual headache alone or in combination with
other neurological symptoms. If CVT is proven, blood screening for coagulation abnormalities should be performed. On the other hand, diagnostics for finding the cause of CVT should include blood tests of thyroid function. Early treatment of CVT and hyperthyroidism is mandatory.