A Case of Spontaneous Acute Subdural Hemorrhage Caused by a Dural Arteriovenous Fistula on the Convexity without Cortical Venous Reflux.

Bleeding from a dural arteriovenous fistula (DAVF) typically occurs in the form of an intracerebral or subarachnoid hemorrhage. Here, we report a rare case of a DAVF with an acute subdural hematoma (ASDH). A 29-year-old male presented to the emergency department with a complaint of progressing headache and nausea, with no reported episode of head trauma. Non-contrast CT revealed a left ASDH with a moderate midline shift. Digital subtraction angiography revealed a DAVF on the left parietal convexity. The DAVF was fed by the middle meningeal artery and drained into the superior sagittal sinus and the sphenoparietal sinus via the diploic vein without cortical venous reflux. The DAVF was treated with transarterial embolization using 25% diluted n-butyl cyanoacrylate prior to hematoma removal. The bleeding point was confirmed on the inner surface of the dura mater. The patient recovered well without any neurological deficits.