A Rare Case of First-Time Seizure Induced by Cerebral Venous Sinus Thrombosis Following the Use of Tranexamic Acid for Menorrhagia

<b>Background and clinical significance:</b> Tranexamic acid (TXA) is commonly used for menorrhagia. Common side effects include diarrhoea, nausea, and vomiting. However, more serious and rare side effects, including embolism, thrombosis, and seizures, are less commonly considered. <b>Case presentation:</b> We report the case of a 39-year-old woman of Asian origin who presented after a first-time seizure while driving, following starting tranexamic acid for menorrhagia seven days prior. She complained of a headache, nausea, neck stiffness, floaters, and blurred vision. Her lactate was elevated on presentation. On examination there were no neurologic abnormalities. A computed tomography (CT) head scan showed acute haemorrhagic foci along the left temporal lobe. This prompted a CT venography, which showed filling defects in the left transverse and sigmoid sinuses, in keeping with cerebral venous sinus thrombosis. MRI of the head further showed a blooming artefact, indicating secondary thrombosis of the lateral tentorial sinus on the left side extending into the vein of Labbe. Following the diagnosis of cerebral venous sinus thrombosis, the patient was started on regular levetiracetam as well as a therapeutic dose of low molecular weight heparin. Since the initial episode, she has been seizure-free for over three months now. <b>Conclusions:</b> This case highlights the importance of considering less common side effects of tranexamic acid in patients who are taking TXA and are presenting with first-time seizures and headaches. These patients should be monitored for embolic-related intracranial events. A careful diagnostic approach, including cerebrovascular imaging, is essential for an accurate diagnosis and effective treatment.