Pearls & Oy-sters: Grisel Syndrome Presenting as Pseudodystonia: A Twist in the Neck

Abstract

Pseudodystonia is a term that describes abnormal postures, repetitive movements, or both, where clinical analysis, imaging, laboratory or electrophysiological investigations indicate that these movements are not consistent with dystonia. Grisel’s syndrome (GS), characterised by rotatory subluxation of the atlantoaxial joint (AAJ) due to non-traumatic causes, is a cause of pseudodystonia. GS is seen in children less than 12 years of age, and should be suspected in patients with acute onset of painful torticollis. We report two girls, aged 9 and 6 years, who developed painful torticollis following upper respiratory tract (URT) infection. They were thought to have cervical dystonia and referred to a movement disorder specialist for botulinum neurotoxin therapy (BoNT). Magnetic resonance imaging (MRI) of the cervical spine showed type I and type II rotary AAJ subluxation respectively, which confirmed the diagnosis of GS. Short tau inversion recovery (STIR) hyperintensity was noted suggesting AAJ edema without any bone erosion or cord compression. Abruptness of onset, presence of severe pain, resistance to passive neck movements, fixed postures present equally in rest and action, absence of sensory trick, and persistence in sleep favor pseudodystonia. Both subjects improved with conservative treatment, which included temporary immobilization of the cervical spine and anti-inflammatory drugs. Early identification and treatment is imperative to avoid neurological complications, like high cervical compressive myelopathy, which can lead to quadriplegia and respiratory distress. Prominent sternocleidomastoid (SCM) contraction ipsilateral to the rotated chin helps to clinically identify GS.