Cerebral Venous Thrombosis Associated With Graves Hyperthyroidism

Abstract

Objective: We report a case of cerebral venous thrombosis (CVT) associated with Graves hyperthyroidism in order to increase awareness of this association in the literature. CVT entails significant morbidity and mortality, and awareness of its risk factors may assist both with expediting its diagnosis and completing an appropriate workup. Methods: A 62-year-old female with a 3-week history of symptoms of hyperthyroidism secondary to Graves disease, and a 2-week history of treatment with methimazole, presented with sudden onset of severe headache, right-sided weakness, and generalized seizure. Results: A computed tomography scan of her head identified extensive CVT, located within the superior sagittal sinus and extending into the right transverse sinus. She remained biochemically hyperthyroid at the time of her presentation (thyroid-stimulating hormone = 0.10 mIU/L; free thyroxine = 32.8 pmol/L; free triiodothyronine = 10.0 pmol/L). A thrombotic workup revealed normal antithrombin, protein C, and protein S levels; normal platelet count, international normalized ratio, and activated partial thromboplastin time; and negative cytoplasmic antineutrophil cytoplasmic antibodies (ANCA), perinuclear-ANCA, antinuclear antibody, and extractable nuclear antigen antibodies. Factor VIII concentration was abnormally elevated at 3.63 IU/mL (normal, 0.50 to 1.50 IU/mL). Conclusion: Our case highlights the risk of CVT with Graves hyperthyroidism likely related to coagulopathy from Factor VIII elevation. Patients presenting with stroke and hyperthyroidism should be investigated for possible CVT, and if the diagnosis is confirmed, should receive prompt initiation of anticoagulation. Abbreviations: CVT = cerebral venous thrombosis; FT4 = free thyroxine