From the Guidelines
Blood tests for chorea should include genetic testing for Huntington's disease, complete blood count, metabolic panel, thyroid function tests, antiphospholipid antibodies, and anti-streptolysin O titers to identify the underlying cause of chorea. These tests help determine the specific cause of chorea, which can result from various conditions, including genetic disorders, autoimmune conditions, metabolic disturbances, and infections.
Key Blood Tests
- Genetic testing for Huntington's disease (looking for CAG repeat expansions in the HTT gene) is crucial when Huntington's disease is suspected, especially with a positive family history 1.
- Blood tests for autoimmune conditions like lupus (ANA, anti-DNA antibodies) may be ordered if autoimmune chorea is suspected.
- Thyroid function tests help identify hyperthyroidism, which can cause chorea.
- Anti-streptolysin O titers are important for diagnosing Sydenham's chorea following streptococcal infections.
- Metabolic panels help identify electrolyte disturbances or liver dysfunction that can cause movement disorders.
- Copper and ceruloplasmin levels may be checked to rule out Wilson's disease, particularly in younger patients with movement disorders 1.
Clinical Considerations
These tests are typically ordered based on clinical presentation, age of onset, and family history to determine the specific cause of chorea and guide appropriate treatment. A thorough pediatric and neurological evaluation is necessary to consider the possibility of an organic psychosis and to rule out other neurological or medical problems 1.