SUN-382 Thyrotoxicosis as a Potential Contributor to Cerebral Venous Thrombosis

Abstract Disclosure: S. Malik: None. O. Radpour: None. Background: Cerebral venous thrombosis (CVT) is a rare cause of stroke, more common in young women, and results from clot formation in the cerebral venous sinuses and/or veins. Although uncommon, thyrotoxicosis has been identified in some cases as a contributing factor due to its pro-thrombotic effects. We report a case of CVT in a woman with newly diagnosed hyperthyroidism and no prior history of endocrine or coagulation disorders. Case PresentationA 44-year-old previously healthy woman with a remote history of migraines presented to urgent care with severe headaches. A non-contrast brain CT was unremarkable, and she was discharged with pain management. Over the following days, she developed recurrent right-sided headaches radiating to the neck, accompanied by upper extremity weakness and sensory loss. She presented to the emergency department for further evaluation.She denied smoking, oral contraceptive use, trauma, or family/personal history of thrombophilia. CT angiography of the head and neck with venous sequences showed thrombosis of the superior sagittal sinus, right transverse and sigmoid sinuses, with extension into the right internal jugular vein. No evidence of intracranial hemorrhage, infarction, or increased intracranial pressure was found.She was admitted to the ICU and started on IV heparin. Neurology and Neurointerventional Radiology teams advised continued medical management. A hypercoagulable workup was deferred to outpatient follow-up. A recent mammogram was normal. Laboratory tests, including CBC, Liver function tests and lupus panel, were within normal limits.Thyroid function testing revealed suppressed TSH <0.008 uIU/mL, elevated free T3 at 7.3 pg/mL, and free T4 at 3.53 ng/dL. Thyroid microsomal antibodies were positive (73 IU/mL). Thyroid ultrasound showed a heterogeneous multinodular goiter. These findings supported a diagnosis of thyrotoxicosis due to previously unrecognized Graves' disease. She was initially started on propylthiouracil (PTU) 200 mg three times a day, cholestyramine three times a day and hydrocortisone. 50 mg IV three times a day. Her symptoms progressively improved, with resolution of headaches and regained motor function. Follow-up brain MRI revealed bilateral small parietal infarcts with petechial hemorrhagic conversion. She was transitioned to apixaban 5 mg twice daily for ongoing anticoagulation prior to discharge and methimazole 30 mg daily. Conclusion: Although rare, CVT can be a presenting complication of thyrotoxicosis. Given the high prevalence of thyroid disorders, particularly in women, clinicians should consider thyroid dysfunction as a potential contributing factor in CVT cases. Early detection and treatment of thyrotoxicosis can reduce the risk of life-threatening thrombotic events. Presentation: Sunday, July 13, 2025