Association of Tourette Syndrome and Chronic Tic Disorder With Cervical Spine Disorders and Related Neurological Complications

Abstract

Importance: Severe forms of Tourette syndrome or chronic tic disorder (TS/CTD) may involve repeated head jerking. Isolated case reports have described a spectrum of severe neck disorders in individuals with TS/CTD. However, the nature and prevalence of cervical spine disorders in TS/CTD are unknown.

Objective: To establish if TS/CTD are associated with an increased risk of cervical spine disorders and related neurological complications compared with individuals from the general population.

Design, setting, and participants: All individuals born from 1973 to 2013 and living in Sweden between 1997 and 2013 were identified. Individuals with a record of TS/CTD diagnosed in specialist settings were matched on age, sex, and county of birth with 10 unexposed individuals randomly selected from the general population. Cox proportional hazards regression models were used to estimate the risk of vascular and nonvascular cervical spine disorders among exposed individuals, compared with unexposed individuals. Models were adjusted for other known causes of cervical spine injury. Data were analyzed from March 19 to May 16, 2021.

Exposures: International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnoses of TS/CTD in the Swedish National Patient Register.

Main outcomes and measures: Records of cervical vascular disorders (ie, aneurysm, cerebral infarction, transitory cerebral ischemia) and cervical nonvascular disorders (ie, spondylosis, cervical disc disorders, fractures of the cervical spine, cervicalgia) and cervical surgeries. Covariates included rheumatic disorders, traffic injuries, fall- or sport-related injuries, and attention-deficit/hyperactivity disorder comorbidity.

Results: A total of 6791 individuals with TS/CTD were identified (5238 [77.1%] were male; median [interquartile] age at first diagnosis, 15.6 [11.4-23.7] years) and matched to 67 910 unexposed individuals. Exposed individuals had a 39% increased risk of any cervical spine disorder (adjusted hazard ratio, 1.39; 95% CI, 1.22-1.59). Adjusted hazard ratios for cervical vascular and nonvascular disorders were 1.57 (95% CI, 1.16-2.13) and 1.38 (95% CI, 1.19-1.60), respectively. Risks were similar among men and women.

Conclusions and relevance: Individuals with severe TS/CTD are at increased risk of cervical spine disorders. These outcomes are relatively rare but may lead to persistent disability in some individuals and thus require close monitoring to facilitate early interventions.

Figure 1.. Magnetic Resonance Imaging (MRI) Demonstrating Extensive Injury to the Cervical Cord Secondary to Severe Motor Tics in a Patient With Tourette Syndrome

A, A sagittal T2-weighted image demonstrates hyperintense T2 signal in the cord extending from the level of the third cervical vertebra to the sixth cervical vertebra (arrowheads). The hyperintense cord signal is consistent with cord gliosis secondary to myelopathic cord injury from severe motor tics. There has been surgical removal of the posterior elements from the fourth to sixth vertebrae. This posterior decompression provided more space to the spinal cord, which helps to minimize further cord injury. B, Axial T2-weighted image in the same patient demonstrates the bilateral nature of the cord signal, including involvement of the cord gray matter (arrowheads). Note the cord atrophy in panels A and B.

Figure 2.. Cumulative Incidence of Any Cervical Spine Disorders in the Subcohort of Individuals Followed Up From Age 3 Years

Cumulative incidence under the assumption of no competing risks estimated as 1 − the Kaplan-Meier estimate of survival function (with 95% CIs) of any cervical spine disorders in the subcohort of individuals who were followed up from age 3 years (3298 individuals with Tourette syndrome/chronic tic disorder and 32 980 matched controls). The shaded area represents the confidence intervals.