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

Discussion

We present 2 children with Grisel syndrome (GS), initially misidentified as cervical dystonia, who improved completely with accurate diagnosis and conservative treatment. Pseudodystonia is defined as abnormal postures and/or repetitive movements resulting from causes not compatible with dystonia.¹ GS is a clinical condition characterized by a rotatory subluxation of the AAJ due to nontraumatic causes. Although rare, it is a potentially fatal cause of pseudodystonia in children below 12 years of age. GS should be suspected in children with acute-onset torticollis, restricted painful neck movements, and prominent SCM ipsilateral to the rotated chin, especially in the setting of a recent URT infection or intervention (e.g., tonsillectomy, adenoidectomy, mastoidectomy, tympanoplasty, uvulectomy, or cochlear implantation). Early identification and treatment is imperative to avoid complications like high cervical compressive myelopathy.^2,3

Identification of pseudodystonia is critical in formulating a diagnostic and treatment approach. Pseudodystonia causing torticollis can be due to various etiologies. They can be classified into musculoskeletal disorders without coexisting neurologic abnormalities (GS, congenital vertebral anomalies such as Klippel-Feil syndrome, congenital muscular torticollis [a rare congenital musculoskeletal disorder with unilateral shortening of SCM]), lesions of the posterior fossa and cervical cord (tumors/cysts), primary neurologic conditions (trochlear/abducens palsy and vestibulopathy), benign paroxysmal torticollis, infections like retropharyngeal abscess, and Sandifer syndrome (SS).^1,4 In SS, it is thought that the tilted head position probably yields relief from the discomfort caused by acid reflux. Abrupt onset, severe pain, resistance to passive neck movements, fixed posture present equally at rest and action, absence of sensory trick, and persistence in sleep favor pseudodystonia.¹ Patients with dystonia have insidious onset (except due to dopaminergic blocking agents and rapid onset dystonia-parkinsonism), experience sleep benefit, lack painful restriction of joint movements, and have action-induced overflow dystonia to unaffected muscles initiated by voluntary movement overtime. Antecedent URT infection or surgery is an additional clue to GS.² Severe pain is also associated with other pseudodystonias, such as stiff-person syndrome or painful tonic spasms of multiple sclerosis and neuromyelitis optica.¹

Initially described by Sir Charles Bell in 1830, GS was named after a French otorhinolaryngologist, Pierre Grisel, who reported 3 such children in 1930.³ Although most cases were reported following URT infection (57.7%) and otorhinolaryngeal surgeries (37.8%), there have been reports of GS following gastrointestinal infections, meningitis, and Kawasaki disease (KD) with a mean delay in diagnosis being 33 days.² Two-thirds of cases are in children, without any sex predilection. Greater predominance in children is ascribed to considerable ligamentous laxity of the cervical region, hypermobility of C1 on C2 with greater atlas-dens interval, weak cervical muscles, immature bone formation, horizontally oriented facet joints, larger synovial folds in occipito-AAJs, and an increased frequency of URT infections.² Alar and transverse ligaments are characteristically lax in children. A system of pharyngovertebral veins which originate in the posterosuperior pharynx, traverse the prevertebral fascia, and drain in the periodontoidal plexus. This extends inflammation from the pharynx to the atlantoaxial ligaments, leading to ligamental laxity aggravated by regional hyperemia and inflammation.³ Association with diseases harboring ligamentous laxity like Down and Marfan syndrome has led to the currently postulated 2-hit hypothesis of GS, implicating muscle spasm following an infection or surgery in a child who is predisposed by lax cervical ligaments.²

The association of GS with KD has led to the postulation of AAJ subluxation due to postinfectious immune-mediated joint inflammation similar to Reiter syndrome. GS can occur as a complication in 0.6% patients with KD, all of whom had cervical lymphadenopathy and received IV immunoglobulin with aspirin within 10 days from fever onset along with cervical collar and resolved without neurologic impairment.⁵

This acute painful torticollis has been labeled as cock-robin position [Figure 1 H (inset)], and children find it impossible to turn the head past the midline even transiently. Prominence of the SCM ipsilateral to the tilted chin, contrary to the prominent contralateral SCM in cervical dystonia, is highly suggestive of GS.^2,3 This is a compensatory muscle spasm to limit the head tilt, induced by joint subluxation. Dystonic torticollis is a basal ganglia disorder induced by aberrant afferent inputs from the cerebellum characterized by loss of inhibition within the sensorimotor circuitry, disrupted sensorimotor integration, and maladaptive homeostatic plasticity where the bulkier, overactive SCM is contralateral to the side of tilted chin.

MRI of the cervical spine would be the first investigation for making a diagnosis and ruling out other causes of pseudodystonia by evaluation of cervical soft tissues, ligaments, and spinal cord. CT of the cervical spine with 3-dimensional reconstruction is the gold standard for confirmation and grading of AAJ subluxation. The Fielding Hawkins classification grades the rotary subluxation of the AAJ as type I (rotation of the atlas and ≤3-mm anterior displacement), type II (3–5-mm displacement), type III (>5-mm displacement), and type IV with posterior displacement, of which the last is very rare.⁶ Type I and II (our case scenarios) are more common and are amenable to conservative management with antibiotics, anti-inflammatory drugs, and external immobilization, whereas type III and IV may need more aggressive surgical management.⁷ Literature review shows that only 12% of GS had undergone surgery as a first- or second-line treatment.² Complications in GS may vary from local pain, paresthesia, lower cranial nerve palsies, quadriparesis/plegia, and death.^2,3 Identifying the clinical clues in an acute-onset painful torticollis in a child and confirmation of GS with CT or MRI are cardinal in management of this treatable condition.