Chorea - Ballismus

Related Subjects: |Neurological History taking

🕺 The term "chorea" comes from the Greek "choreia", meaning "dance," highlighting the irregular, flowing movements seen in patients. 💥 Ballismus is considered an extreme form of chorea, producing violent, large-amplitude, flinging movements, usually of one side of the body (hemiballismus).

ℹ️ About

• Chorea and Ballismus are hyperkinetic movement disorders linked to dysfunction of the basal ganglia circuitry.
• Chorea → abrupt, unpredictable, "dance-like" movements; Ballismus → more violent and proximal flinging limb movements.
• Despite abnormal movements, muscle strength is typically preserved until late disease stages.

🩺 Clinical Features

• Involuntary, irregular, brief, and non-rhythmic movements 🌊.
• Movements worsen with stress or voluntary action and disappear during sleep 😴.
• Milkmaid’s grip sign: patient unable to maintain steady grip 🤲.
• Clumsy gait 🚶 and difficulty with fine motor tasks.
• Explosive, staccato dysarthric speech 💬.
• Ballismus: Classically hemiballismus due to contralateral subthalamic nucleus lesions.

🧬 Pathophysiology

• Normal movement requires a balance between excitatory (dopamine) and inhibitory (acetylcholine, GABA) basal ganglia circuits.
• In chorea/ballismus, there is reduced inhibitory GABAergic output from the striatum → excessive thalamic excitation → hyperkinetic movements 🔄.
• Hemiballismus usually results from a lesion in the subthalamic nucleus (stroke is the commonest cause).

📌 Causes of Chorea

• 🦠 Rheumatic fever – Sydenham’s chorea (immune-mediated).
• 🧬 Huntington’s disease (trinucleotide repeat disorder).
• 🌸 Systemic lupus erythematosus (SLE) and antiphospholipid syndrome.
• 👵 Senile chorea – idiopathic, in elderly.
• 🤰 Chorea gravidarum – pregnancy or OCP-related.
• 🥉 Wilson’s disease (copper metabolism defect).
• 🧒 Ataxia telangiectasia (childhood neurodegeneration).
• 🩸 Neuroacanthocytosis (spiky RBCs, movement disorder).
• 🧑‍⚕️ HIV-related chorea.
• 🧩 Dentatorubral-pallidoluysian atrophy (DRPLA).
• 🔥 Hyperthyroidism.
• ☣️ Toxins/poisons – CO, manganese, organophosphates.
• 💊 Drug-induced – levodopa, neuroleptics, OCPs.

🔍 Investigations

• Bloods: U&E, LFTs, TFTs (exclude metabolic/systemic causes).
• ASOT / Anti-DNAse B: evidence of recent streptococcal infection (Sydenham’s chorea).
• Autoantibodies: ANA, antiphospholipid, anti-basal ganglia antibodies.
• MRI Brain: look for basal ganglia or subthalamic lesions (especially in ballismus).
• Echocardiogram: if rheumatic fever suspected (valvular involvement).

💊 Management

• Tetrabenazine – depletes presynaptic dopamine (effective for Huntington’s chorea) but monitor for depression/suicidal ideation ⚠️.
• Dopamine antagonists: Haloperidol (low dose) or Quetiapine – useful for symptomatic control.
• Valproate / Carbamazepine: sometimes used if seizures co-exist.
• Sydenham’s chorea: Consider steroids or immunotherapy in severe cases, alongside secondary prophylaxis against rheumatic fever.
• Underlying cause: e.g. treat thyrotoxicosis, stop offending drugs, chelation for Wilson’s disease.

🧾 Exam Pearls

✅ "Milkmaid’s grip" → pathognomonic for chorea.
✅ Hemiballismus → contralateral subthalamic nucleus lesion (usually vascular).
✅ Always ask about family history, rheumatic fever, and autoimmune disease.
✅ Movement disorders often worsen with voluntary movement and stress but improve with sleep.

Cases - Chorea

• Case 1 - Huntington’s Disease: A 42-year-old man presents with progressive involuntary jerky movements of his arms and face. He has mood changes, irritability, and memory decline. Family history: father died in his 50s with similar symptoms. Diagnosis: Huntington’s disease (autosomal dominant, CAG repeat expansion). Management: Symptomatic (tetrabenazine for chorea, SSRIs for depression); genetic counselling.
• Case 2 - Sydenham’s Chorea: A 13-year-old girl develops purposeless, irregular movements of her hands and face, causing handwriting deterioration. She had sore throat 6 weeks ago. Exam: milkmaid’s grip, emotional lability. Diagnosis: Sydenham’s chorea (post-streptococcal, rheumatic fever manifestation). Management: Supportive; haloperidol/valproate if severe; long-term penicillin prophylaxis.
• Case 3 - Drug-Induced Chorea (Levodopa): A 70-year-old man with Parkinson’s disease on high-dose levodopa develops writhing and jerky limb movements interfering with activities of daily living. Diagnosis: Levodopa-induced dyskinesia (chorea). Management: Adjust dopaminergic therapy (reduce levodopa dose, add amantadine, consider deep brain stimulation if refractory).

Teaching Commentary 🧠

Chorea is an involuntary, irregular, non-rhythmic movement disorder due to basal ganglia dysfunction. Major causes: - Genetic: Huntington’s disease. - Post-infective: Sydenham’s chorea (rheumatic fever). - Drug-induced: levodopa, antiepileptics, antipsychotics. - Metabolic/other: Wilson’s disease, SLE/antiphospholipid, thyrotoxicosis. Management depends on the cause: supportive, symptomatic suppression (dopamine depleters/antipsychotics), and treating underlying disease. Always think of age + context to narrow the differential.