Hemichorea

Hemichorea is characterized by one-sided involuntary movements and can result from various causes. Treatment depends on the underlying condition and may involve addressing the cause, withdrawing medications, using dopamine blockers, VMAT2 inhibitors, or other medications. In severe cases, surgical options like DBS may be considered.

2024-01-06 21:00:44 - Editor

Hemichorea Overview:

Hemichorea is characterised by involuntary movements which are rapid, non-patterned and confined to one side of body. Hemichorea and hemiballismus (high amplitude, violent, flinging and flailing movements confined to one side of body) usually occur together and is referred as hemichorea hemiballismus syndrome (HCHB). It usually occurs due to vascular or metabolic insult affecting the basal ganglia. Other causes include infections, autoimmue, medications, such as metochopramide, prochlorperazine or pregnancy related (chorea gravidarum). Metabolic causes include hyperglycaemia, hypernatremia, hypomagnesaemia, and hypocalcaemia. HIV, toxoplasmosis, TB and syphilis have also been reported as causes of infectious chorea. Sydenham chorea is the commonest cause of infectious hemichorea in childhood. Autoimmune hemichorea is caused by autoimmune encephalitis, Systemic Lupus erythromatosis (SLE), Behçet disease, Antiphospholipid antibody syndrome, Celiac disease and Hashimoto thyroiditis. (1, 2, 3)

Symptomatic Management of Hemichorea:

Hemichorea often improves with appropriate treatment of the underlying cause and/or withdrawal of the offending drug. The majority of the cases have a good prognosis. Symptomatic management of hemichorea includes dopamine receptor blockers, such as, first generation antipsychotic agents, second generation antipsychotic drugs or vesicular monoamine transporter type 2 (VMAT2). (4)

Antipsychotic Agents for Hemichorea:

First generation antipsychotic agents include chlorpromazine at an initial dose of 25 mg/ day. Second generation antipsychotic drugs, such as, risperidone (0.5- 1mg once or twice daily), olanzapine at a starting dose of 5mg daily up to a maximum dose of 30 mg daily, and aripiprazole at 2.5 mg daily, with slow escalation up to 15 mg daily. Second generation antipsychotic agents could help to reduce severity of hemichorea with a better safety profile than first generation agents. (4, 5, 6)

Dopamine Depleting Agents:

Dopamine depleting agents act by inhibiting vesicular monoamine transporter type 2 (VMAT2) receptors. They include tetrabenazine (12.5 mg daily, as a starting dose) and deutetrabenazine (6mg/day up to a maximum of 48 mg/day). (7)

Other Medical Treatments:

Medical treatment options include carbamazepine (100 - 400 mg/day), topiramate (25- 50 mg daily) and Levetiracetam (500 mg twice daily). The effectiveness of these agents has not yet established. (8, 9, 10) Also, botulinum toxin has been tried in the management of hemichorea. However its efficacy is not well studied. (11) Finally, surgical option including deep brain stimulation (DBS), pallidotomy or thalamotomy is not well studied and patients should be selected carefully. (12)

References

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