[Arnold-Chiari malformation with multiple paroxysmal manifestations induced by coughing].

We present a 66-year old woman suffering from a chronic disorder characterized by multiple paroxysmal symptoms precipitated by coughing. These included cephalalgia, syncope, binocular photopsia phenomena with blurred vision, and an "electric-like" paroxysmal tingling of the hands. In addition to a central spinal cord cavity and hindbrain herniation, magnetic resonance imaging showed multiple skeletal anomalies and the craniospinal junction which included a narrow clivo-axial angle, basilar impression of the skull and a tight foramen magnum. Resonance magnetic imaging showed a high-signal intensity lesion on T2-weighted images at the posterior medullo-spinal junction suggesting focal demyelination. We propose that paroxysmal symptoms induced by coughing in patients bearing hindbrain ectopia and skeletal anomalies at the foramen magnum region may involve different pathogenetic mechanisms, including ectopic axonal activity and ephaptic transmission at the sensory pathways. This caused a Lhermitte-like phenomenon precipitated by coughing, rather than by forward flexion of the neck. However, increased pressure at the posterior fossa presumably underlies all these phenomena, and may therefore be potentially relieved by suboccipital decompressive craniotomy.