A Case of Perimesencephalic Subarachnoid Hemorrhage with Cerebral Venous Sinus Thrombosis due to Stenosis of the Junction of the Vein of Galen and Rectus Sinus.

Perimesencephalic subarachnoid hemorrhage (PMSAH) is a group of diseases characterized by bleeding around the brainstem. In recent years, it has been suggested that PMSAH is associated with the venous system. We report a case of PMSAH caused by stenosis of the junction of the vein of Galen (VG) and the rectus sinus (RS). A 39-year-old man presented with restlessness at work. He was administered diazepam, and a few minutes later, his consciousness became clear. Imaging showed subarachnoid hemorrhage (SAH) around the right midbrain, occlusion of the right sigmoid sinus and the right transverse sinus, stenosis of the junction of the VG and RS, T2 hyperintensity in the right middle temporal gyrus, and obstruction of the right vein of Labbe. The location of the SAH coincided with stenosis of the junction of the VG and RS. PMSAH was diagnosed due to the increase in intracranial venous pressure caused by the patient's sinus obstruction in addition to the stenosis of the junction of the VG and RS. It is necessary to pay attention to venous return when PMSAH is observed.