Treatment Strategies for Dystonia: Medical and Surgical
Treatment Stratrgies for Different Populations - Specific Treatments for Special Populations
Wilson’s Disease
Very effective treatments are available for a few rare disorders where dystonia may be a presenting or dominating feature on examination.[20-22] Wilson’s disease is the prototype example, where copper chelation therapy can prevent progression and even reverse disability. Because Wilson’s disease has a fatally progressive course without treatment, it should be excluded with appropriate diagnostic testing in every child and young adult with dystonia. A low serum ceruloplasmin and a slit lamp exam by an ophthalmologist looking for the presence of Kaiser-Fleischer rings provide useful screening tests. This may be followed by urinary tests of copper excretion and/or liver biopsy if uncertainty regarding the diagnosis remains.
Dopa-Responsive Dystonia
Although dopa-responsive dystonia constitutes only 5-10% of all childhood dystonias, a trial of levodopa is warranted in all children and young adults with dystonia because of its dramatic and sustained efficacy.[23] Among those who respond to levodopa, a role for confirming the diagnosis via testing for biopterin metabolites in the CSF remains unclear. A phenylalanine challenge test also has been proposed, but is not widely used. However, a simple genetic test is available for the most common type associated with mutations in the GCH1 gene.
Other Specific Mechanism-based Treatments
As ongoing research reveals additional causes for dystonia, the numbers of disorders with specific mechanism-based treatments has continued to grow. Formal published guidelines for which disorders to consider and what tests to employ are not available. The following disorders should be considered in the appropriate clinical setting. Biotin-responsive basal ganglia disease is a very rare condition that may present with prominent dystonia in children or young adults, often in combination with other neurological signs including Parkinsonism, ocular motility defects, and episodes of encephalopathy.[24-26] An important clue is peculiar signal changes in the caudate and putamen on MRI. Symptoms can be reversed with biotin supplements; death ensues if the disorder untreated.
Vitamin E deficiency is dominated by ataxia with neuropathy, but dystonia often is a presenting feature and may predominate in later stages.[27-29] Serum vitamin E levels are useful for diagnosis, and treatment involves dietary supplements. Deficiency of the glucose transporter, GLUT1, due to mutations in the SLC2A gene classically presents with psychomotor delay, seizures, and a mixed motor disorder. A more recently recognized phenotype of GLUT1 deficiency is paroxysmal exercise-induced dystonia. The diagnosis can be made via a genetic test and effective treatment requires a ketogenic diet.
H. A. Jinnah, MD PhD
Emory University School of Medicine
Atlanta, GA 30307
