Cerebral venous sinus thrombosis (CVST) is a rare but potentially life-threatening condition caused by clot formation in the cerebral veins and dural sinuses. Risk factors include hypercoagulable states, pregnancy, malignancy, infections, medications, and systemic inflammatory disorders. Severe iron deficiency anemia (IDA) is an uncommon cause of CVST. Iron deficiency may promote thrombosis via reactive thrombocytosis, increased blood viscosity, oxidative stress, and endothelial dysfunction. Here, we present a rare case of CVST in the setting of severe iron deficiency anemia.

A 51-year-old woman with uterine fibroids, menorrhagia, and IDA presented with one week of fatigue, dizziness, lightheadedness, and persistent headache with nausea and vomiting. Initial CT imaging was unremarkable. Labs revealed severe anemia (hemoglobin 3.4 g/dL) and thrombocytosis (platelets 850k/µL). She underwent myomectomy for a large uterine fibroid with plans for outpatient hysterectomy. During hospitalization, her headache worsened. MRI and CT angiogram were normal, but CT venogram revealed near-occlusive thrombosis of the distal transverse sinuses, left sigmoid sinus, and proximal right sigmoid sinus. Therapeutic heparin was initiated and repeat imaging five days later showed improvement. Extensive evaluation for hypercoagulable disorders and occult malignancy was negative. The CVST was attributed to severe IDA. She was transitioned to oral anticoagulation with neurology follow-up.

This case highlights the rare occurrence of CVST secondary to severe iron deficiency anemia. Clinicians should maintain a high index of suspicion for CVST in patients with profound anemia presenting with persistent or worsening headaches. Prompt recognition and treatment of iron deficiency not only reduce thrombotic risk but may also limit the intensity or duration of anticoagulation. Addressing modifiable risk factors is essential in optimizing outcomes for patients with CVST.