Differentials in the diagnosis of Tourette Syndrome

• Chronic tic disorder: Single or multiple motor or vocal tics (not both) occur for more than 12 months*

• Transient tic disorder: Single or multiple tics occur for at least or more than 4 weeks but for 12 or less consecutive months*

• Tardive Tourettism: Dyskinesia induced by neuroleptic drugs (antipsychotics) such as haloperidol, risperidone, pimozide etc

• Epilepsy: Patient has seizures or fits usually with jerking movements & associated with loss of consciousness

• Dystonia: twisting/contraction of specific muscle groups. Can affect face but typically the legs. Dystonia is usually progressive

• Myoclonic epilepsy: A form of epilepsy in which jerking movements occur but without loss of consciousness

• Affective Disorder: Depression is one of the most common misdiagnoses of Tourette Syndrome NB:CNS serotonin & nor-adrenaline tend to be low

• Affective / Mood disorder: Bipolar Affective Disorder has been a frequent misdiagnosis

• Autistic Spectrum Disorder/Asperger's: Many shared symptoms. NB: Can co-occur with Tourette Syndrome

• Sydenham's Chorea: A movement disorder (St. Vitus Dance). Rheumatic fever common aetiological factor (75%)

• ADD/ADHD: Very frequent misdiagnoses in TS. Attention deficit & hyperactivity are very common aspects of Tourette Syndrome

• Allergy: Common misdiagnosis in the past. Carefully assess/eliminate possible hypersensitivity/allergans

• Spasmodic torticollis: Including 'Wry Neck' > more prevalent between ages of 30 - 50 years

• Psychosis/schizophrenia: Not a true differential as little symptom overlap > but misdiagnoses have occurred. The presence of neuroleptic side-effects can be a confusing factor (e.g. tardive dyskinesia / hyperkineses)

*Classification of Tic disorders (Click to enlarge)

Table taken from: Advances in understanding and treatment of Tourette syndrome. Nat Rev Neurol 2011 Dec; 7(12):667-76.