Dural Arteriovenous Fistula of the Medulla Initially Mimicking Guillain-Barré Syndrome

A 65-year-old woman who was previously well presented with 2 days of ascending flaccid quadriparesis. This had been preceded by 2 weeks of gastroenteritis, with an episode of urinary incontinence at onset. On admission, she was catheterized for urinary retention. She was areflexic in her lower limbs, and power was markedly reduced proximally (1/5) more than distally (4/5). In the upper limbs, her reflexes were present with reinforcement, with global reduction of power (4/5). Her presentation was felt to be consistent with Guillain-Barré syndrome. However, her weakness and areflexia improved 12 hours after admission, returning to full power with brisk reflexes in the upper limbs, reduced knee jerks, and absent ankle jerks. Her power continued to fluctuate while on the ward. These atypical aspects pointed away from a diagnosis of Guillain-Barré syndrome¹ and prompted magnetic resonance imaging of the brain and cervical spine, the results of which showed features consistent with a medullary dural arteriovenous fistula, later confirmed by the results of angiography (Figure).