Makindo Medical Notes

Related Subjects: |Sydenham's chorea |Chorea - Ballismus |Huntington's Disease/Chorea |Tetrabenazine

🧠 About

• Sydenham's Chorea: A post-infectious autoimmune neurological disorder with rapid, uncoordinated “dance-like” movements 💃. Strongly associated with acute rheumatic fever (a Jones major criterion). Now rarely seen in the UK due to improved strep infection control.

🧬 Aetiology

• Molecular Mimicry: Antibodies generated after Group A β-haemolytic streptococcus infection cross-react with basal ganglia antigens → abnormal motor signalling.
• Recurrence Triggers: Pregnancy 🤰 (chorea gravidarum), oral contraceptives 💊, and certain drugs (digoxin, phenytoin).
• Typically presents in children or adolescents, more common in girls.

🤒 Clinical Presentation

• Choreiform Movements: Rapid, jerky, purposeless movements of face, hands, and trunk. Can impair handwriting ✍️, feeding, and gait → ↑ falls risk.
• Milkmaid’s Grip Sign: Inability to sustain grip, producing a squeezing–relaxing pattern 🤲.
• Skin: May have associated erythematous macular rash (erythema marginatum) 🌸.
• Neuropsychiatric: Emotional lability, OCD traits, irritability, or frank psychosis.
• Symptoms usually resolve over 3–6 months but may recur years later.

🔬 Investigations

• Blood tests: FBC, U&E, LFTs, ESR/CRP for systemic inflammation.
• ASOT / Anti-DNase B: Evidence of recent strep infection.
• Anti-basal ganglia antibodies: Supportive, though not always positive.
• Brain MRI: Often normal, but may show basal ganglia changes in some cases.
• Echocardiogram: Always check for rheumatic carditis or valvular disease ❤️.

💊 Management

• Antibiotic Prophylaxis: Long-term penicillin prophylaxis to prevent recurrent strep infections (and protect heart valves).
• Symptomatic Control: Haloperidol (low dose), sodium valproate, or quetiapine if movements severe.
• Steroids: May shorten duration if inflammatory drive is prominent.
• Supportive Care: Monitor for psychiatric features, provide reassurance to family, and address educational impact in children.
• Long-term follow-up: Essential to detect recurrences, especially with hormonal triggers (pregnancy, OCPs).

📌 Key Exam Pearls

✅ A Jones major criterion for diagnosing rheumatic fever.
✅ Movements are irregular, jerky, non-repetitive (not tremor).
✅ Differentiate from Huntington’s (progressive, genetic, adult-onset).
✅ Always examine for cardiac murmurs in suspected cases → risk of rheumatic heart disease.

Cases — Sydenham’s Chorea

• Case 1 — Adolescent Girl with Post-Strep Chorea: A 13-year-old girl develops progressive, purposeless jerky movements of her arms and face, interfering with her handwriting and eating. Parents note she drops objects and makes involuntary grimaces. She had a sore throat 6 weeks earlier. Exam: “milkmaid’s grip” and hypotonia. Diagnosis: Sydenham’s chorea (rheumatic fever manifestation). Management: Supportive care; haloperidol or sodium valproate if severe. Start long-term penicillin prophylaxis for rheumatic fever prevention.
• Case 2 — Emotional Lability and Chorea in a Teenager: A 15-year-old boy presents with new-onset irritability, poor school performance, and sudden, fidgety limb movements. Exam: darting tongue movements, absent reflexes, and choreiform gait. Echocardiogram shows mild mitral regurgitation. Diagnosis: Sydenham’s chorea associated with rheumatic carditis. Management: Treat with antipsychotics or valproate if disabling; secondary penicillin prophylaxis; monitor cardiac status.

Teaching Commentary 🧠

Sydenham’s chorea is a delayed autoimmune complication of Group A streptococcal infection, part of acute rheumatic fever. It occurs weeks to months after infection, especially in children/adolescents. Features: involuntary choreiform movements, emotional lability, hypotonia, and functional impairment (writing, walking). It is often self-limiting but may last months. Always consider rheumatic heart disease and institute long-term penicillin prophylaxis. Symptomatic therapy (haloperidol, valproate, carbamazepine) is used for disabling cases.