Torsion Dystonias Workup

Updated: Feb 15, 2016
  • Author: Priyantha Herath, MD, PhD; Chief Editor: Selim R Benbadis, MD  more...
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Workup

Approach Considerations

Routine laboratory and neurophysiological investigations are not recommended as part of workup to diagnosis and classify dystonia. Most often, the diagnosis is clinical. However, a useful investigative algorithm for dystonia workup is given here. 

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Laboratory Studies

The following is recommended when age of onset is younger than 26 years (or the patient has a relative with early-onset dystonia):

  • DYT1 testing (with genetic counseling)

  • If negative for DYT1 testing, consider trial of levodopa

  • If no response to levodopa trial, perform MRI, ceruloplasmin test, and slitlamp examination

The following is recommended when age of onset is older than 26 years:

  • MRI

  • 24-hour copper urinary excretion

To differentiate patients with dopa-responsive dystonia from junvenile Parkinson disease presenting with dystonia, one can consider presynaptic dopaminergic scan (DAT) or fluorodopa (F-DOPA) scanning. [27]

The following is the proposed algorithm for dystonia workup when the history and physical findings show dystonia and other deficits:

  • Possibly tardive condition: Assess for a history of exposure to a dopamine- blocking agent

  • Possibly structural condition: Perform MRI and CT angiography

  • Possibly metabolic and/or neurodegenerative: Perform the following:

    • Trial of levodopa

    • Measurement of 24-hour serum copper excretion

    • Slitlamp examination

  • MRI of brain
  • Blood smear for acanthocytes
  • Antiphospholipid antibody testing
  • Genetic testing for Huntington disease, SCA, mitochondrial diseases
  • Lysosomal screening (GM1, GM2 gangliosidoses)
  • Test for serum and urine organic acids and amino acids
  • Chromosomal analysis
  • Alpha-fetoprotein test
  • Determination of lactate and pyruvate in serum and CSF with the lactate-pyruvate ratio
  • Skin, muscle, and nerve biopsy
  • CSF analysis
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