[Arteriovenous malformation of the brain revealed through a visual blur and Adie's pupil]

Arteriovenous malformations of the brain (BAVMs) are a relatively rare group involving intracranial vascular lesions (telangiectasia, cavernous malformation, venous anomaly). We report the case of a patient who presented an atypical visual symptomatology revealing a BAVM.

A 48-year-old woman consulted for a recent bilateral visual blur. In darkness, discrete anisocoria appeared on the left eye. At the biomicroscopy light examination, we found areflexic semi-mydriasis (direct and consensual) on the left eye; the light reflex (direct and consensual) on the right eye was normal. During the accommodative reflex test the left pupil contracted. We propose the diagnosis of Adie's pupil, which was confirmed by the pilocarpine test (0.125%). We decided to examine the visual field because the symptomatology of the visual blur remained unexplained. The visual field showed a left homonymous inferior lateral scotoma. MRI showed a right occipital arteriovenous malformation.

A quick examination could confuse painless anisocoria with a compression of the IIIrd intrinsic left nerve. This recent scotoma revealed BAVM progression. The natural history of BAVMs shows that the essential risk of these injuries is the onset of an intracranial hemorrhage. To reach a radical therapeutic decision, a cerebral arteriography clarifying the afferent and efferent vascularity of the nidus was carried out.

This case is original in that it associates the concomitant discovery of a BAVM and Adie's pupil. Symptomatic BAVMs are extremely serious. Planning their treatment requires multidisciplinary cooperation in order to reduce the risk of mortality.