Cervical perimedullary arteriovenous fistula in an infant presenting with subarachnoid hemorrhage--case report.

A 9-month-old boy was transferred to our institute after suffering sudden seizure and loss of consciousness followed by cardiopulmonary arrest. Neurological examination on admission revealed deep coma and tetraparesis. Brain computed tomography revealed diffuse intracranial subarachnoid hemorrhage (SAH), whereas brain magnetic resonance (MR) angiography showed no intracranial abnormalities. MR imaging of the spine demonstrated a remarkable flow void extending from C3 to T1. Digital subtraction angiography revealed a perimedullary arteriovenous fistula (AVF) fed by the left thyrocervical trunk, associated with a varix and a dilated perimedullary vein. He had hypoxic encephalopathy due to transient cardiopulmonary arrest, and remained in the intensive care unit for 2 months. Thereafter, he was transferred to the pediatric ward, where his general condition improved, and after 7 months underwent embolization of the AVF to prevent further SAH. The perimedullary AVF was successfully interrupted by transarterial embolization with n-butyl-2-cyanoacrylate and platinum coils, and no additional neurological deficits developed. Post-embolization MR imaging showed loss of the flow void. The favorable outcome demonstrates the importance of spinal cord imaging in infants with SAH without other intracranial abnormalities to detect the presence of perimedullary AVF. Perimedullary AVFs in children are often associated with huge fistulas and varices, so are good candidates for endovascular surgery.