Superior sagittal sinus thrombosis presented as a migraine headache with normal D-dimer: a case report and literature review.

Introduction: Superior sagittal sinus thrombosis (SSST) is a rare type of cerebral venous sinus thrombosis (CVST), characterized by blood clot formation in the superior sagittal sinus, leading to increased intracranial pressure. This report highlights a case of SSST presenting atypically as a migraine with normal D-dimer levels, emphasizing the need for thorough evaluation despite normal laboratory results in at-risk individuals. Presentation: A 49-year-old female experienced a severe unilateral headache, photophobia, dizziness, and neck tension. She had a history of migraines and hypertension. The patient was a heavy smoker and used combined oral contraceptives. Examination revealed neck stiffness and a blood pressure of 150/90 mmHg. Computed tomography and D-dimer tests were normal. Magnetic resonance venography (MRV) revealed SSST and a lacunar infarction. Anticoagulation was initiated, resulting in a good recovery and discharge after 11 days. Discussion: This case illustrates the difficult diagnostic challenge caused by SSST, which initially presented as a primary headache disorder. The occurrence of red flags, including an unusual headache pattern and neck stiffness, justified further investigation. The article also considers the limitations of using D-dimer as a rule-out test in high-suspicion cases, the absolute diagnostic value of MRV, and the effectiveness of standard anticoagulation therapy. Conclusions: This case serves as a reminder that clinical judgment should take precedence over normal laboratory results in patients with unusual headaches and risk factors for CVST. Patients with high-risk and persistent or unusual headaches should be immediately referred for advanced neuroimaging, such as MRV, to facilitate early diagnosis and treatment.