Investigations
1st investigations to order
clinical diagnosis
Test
The diagnosis of tic disorders is made on the basis of the history and a normal physical examination.
No further investigations are necessary unless the presentation and clinical findings suggest other possible differential diagnoses that need to be ruled out.
Result
investigations are only required in the setting of abnormal neurological examination
Investigations to consider
MRI brain with and without contrast
Test
Indicated in patients with an abrupt onset of tics associated with other neurological symptoms, unusual patterns of tics (unilateral or associated with dystonia), onset in adulthood, or an abnormal neurological examination suggestive of secondary causes of tics.
A referral to a neurology specialist is required.
Not indicated in patients with a normal neurological examination.[52]
Result
tic disorder: usually normal; secondary causes of tics: possible abnormalities depending on the condition; signal abnormalities in basal ganglia or brain atrophy may indicate neurodegenerative disorders
electroencephalogram
Test
Indicated only if the history does not help to differentiate between seizures and tics.
No tests are indicated in patients with a normal neurological examination and with a history indicating a tic disorder without a secondary cause.
Result
tic disorder: normal; seizure disorder: epileptiform abnormalities may be present
cerebrospinal fluid analysis (lumbar puncture)
Test
Patients presenting with fever, altered mental status, and abrupt onset of a tic disorder, suggestive of encephalitis, require a lumbar puncture with cerebrospinal fluid studies. Studies include total protein, glucose, cell count and differential, Gram stain, bacterial culture, and viral culture.
A neurologist should be consulted.
No tests are indicated in patients with a normal neurological examination and with a history indicating a tic disorder without a secondary cause.
Result
non-infective cause: normal; infective causes: pleocytosis and elevated protein may be seen
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