Foramen magnum dural arteriovenous fistula presenting with epilepsy.

Intracranial dural arteriovenous fistulas (dAVFs) with perimedullary drainage represent a rare subtype of intracranial dAVF. Patients usually experience slowly progressive ascending myelopathy and/or lower brainstem signs. We present a case of foramen magnum dural arteriovenous fistula with an atypical clinical presentation. The patient initially presented with a generalised tonic-clonic seizure and no signs of myelopathy, followed one month later by rapidly progressive tetraplegia and respiratory insufficiency. The venous drainage of the fistula was directed both to the left temporal lobe and to the perimedullary veins (type III + V), causing venous congestion and oedema in these areas and explaining this unusual combination of symptoms. Rotational angiography and overlays with magnetic resonance imaging volumes were helpful in delineating the complex anatomy of the fistula. After endovascular embolisation, there was complete remission of venous congestion on imaging and significant clinical improvement....