Managing Sydenham’s Chorea: Diagnosis, Treatment, and Prophylaxis

Everything You Need to Know About Sydenham’s Chorea: A Comprehensive Guide for Medical Professionals

Introduction

Sydenham’s chorea, also known as St. Vitus dance, is a rare neurological disorder characterized by involuntary movements, muscle weakness, and emotional instability. It is a key manifestation of acute rheumatic fever (ARF) following a group A Streptococcus (GAS) infection, typically arising weeks to months after an untreated or inadequately treated streptococcal pharyngitis. As a delayed autoimmune reaction, Sydenham’s chorea is one of the most distinctive presentations of ARF, impacting both the nervous system and behavior, and often disrupts daily activities, schooling, and social interactions due to its hallmark jerky movements and mood changes.

With an incidence that has decreased significantly in high-income countries but remains prevalent in areas with limited healthcare resources, Sydenham’s chorea remains an important condition for healthcare providers to recognize and treat effectively. This in-depth guide will cover the pathophysiology, clinical presentation, differential diagnosis, treatment, and long-term management of Sydenham’s chorea. Designed for doctors and medical student, this comprehensive guide offers insight into managing this complex, multifaceted condition.

What is Sydenham’s Chorea?

Sydenham’s chorea is a movement disorder linked to autoimmune inflammation in the basal ganglia following a recent GAS infection. Typically presenting between 5 and 15 years of age, it is considered one of the classic manifestations of rheumatic fever. The condition is distinguished by its rapid, jerky, and unpredictable movements (chorea) that impair voluntary control, often involving the face, hands, and feet. Sydenham’s chorea may develop after a latency period of one to six months following the GAS infection.

Epidemiology

While rare in high-income countries due to advancements in healthcare, especially in the early treatment of strep throat, Sydenham’s chorea remains a significant condition in low- and middle-income countries where ARF incidence is higher. Studies indicate a higher prevalence in girls compared to boys, a trend possibly attributed to hormonal or genetic factors. This gender disparity has implications for understanding the pathophysiology and long-term impacts of the disorder.

For a broader look at the epidemiology and distribution of Sydenham’s chorea and related rheumatic fever, visit the World Health Organization at https://www.who.int/.

Pathophysiology of Sydenham’s Chorea

Sydenham’s chorea results from an autoimmune response to a GAS infection. The disorder is part of a post-streptococcal syndrome driven by molecular mimicry, in which the immune system’s response to bacterial antigens inadvertently targets neuronal tissues in the basal ganglia.

1. Molecular Mimicry and Autoantibody Formation

The M protein on GAS shares molecular structures with certain antigens found in human neuronal tissue, especially within the basal ganglia. The immune system, while attacking GAS, mistakenly produces antibodies that target self-antigens on neurons. This cross-reactivity is central to the disease’s pathogenesis and explains the delayed onset of Sydenham’s chorea following a GAS infection.

2. Basal Ganglia Involvement

The basal ganglia are essential for motor control, coordination, and emotional regulation. In Sydenham’s chorea, inflammation in the basal ganglia disrupts these functions, resulting in the characteristic involuntary movements, muscle weakness, and emotional instability. This involvement also correlates with behavioral symptoms, such as obsessive-compulsive tendencies, commonly seen in affected children.

3. Role of Inflammatory Mediators and Cytokines

In addition to autoantibodies, inflammatory cytokines are implicated in the neuronal damage seen in Sydenham’s chorea. These cytokines contribute to the immune response within the brain, leading to further disruption of neuronal function and exacerbation of symptoms.

For more on autoimmune pathogenesis in Sydenham’s chorea and related disorders, refer to the National Institute of Allergy and Infectious Diseases at https://www.niaid.nih.gov/.

Clinical Presentation of Sydenham’s Chorea

The onset of Sydenham’s chorea is typically gradual, presenting weeks to months after the GAS infection. Symptoms may appear suddenly or worsen progressively over time, interfering with daily activities and impacting quality of life.

1. Motor Symptoms

• Chorea: The involuntary, irregular, and rapid movements are the hallmark of Sydenham’s chorea. These movements commonly affect the face (often seen as grimacing or twitching), hands, and feet, giving rise to the characteristic “dancing” appearance.
• Hypotonia: Many patients experience decreased muscle tone, contributing to a floppy or uncoordinated movement pattern.
• Motor Impersistence: Difficulty maintaining sustained contractions, such as keeping the tongue protruded, is a notable feature and a helpful diagnostic sign.

2. Psychological and Behavioral Symptoms

• Emotional Lability: Sudden mood swings, irritability, and crying spells are frequently reported and can be as disruptive as the physical symptoms.
• Obsessive-Compulsive Symptoms: Some children exhibit obsessive-compulsive behaviors, such as repetitive hand-washing or counting, linking Sydenham’s chorea to the broader category of post-infectious neuropsychiatric disorders.
• Attention Deficits: Difficulties in focusing and concentrating may impact academic performance and daily activities.

3. Other Symptoms of Acute Rheumatic Fever

Given that Sydenham’s chorea is a manifestation of ARF, patients may also present with symptoms associated with ARF, including fever, joint pain, and carditis. Identifying these concurrent symptoms helps support the diagnosis and may guide further management.

For additional information on the clinical manifestations of ARF and Sydenham’s chorea, consult the American College of Rheumatology at https://www.rheumatology.org/.

Diagnosis of Sydenham’s Chorea

Diagnosing Sydenham’s chorea involves a combination of clinical history, physical examination, and laboratory testing to confirm the presence of a preceding GAS infection. The diagnosis is often straightforward in patients with a recent history of streptococcal pharyngitis or other ARF symptoms, though atypical cases may require additional workup.

1. Clinical Assessment

A thorough clinical examination should assess the characteristic choreiform movements, emotional instability, and any supporting ARF symptoms. A history of recent GAS infection is key to confirming the diagnosis, even if the initial infection has resolved.

2. Laboratory Tests

• Throat Culture or Rapid Antigen Detection Test: These tests can confirm a recent or current GAS infection, although they may be negative at the time of chorea onset.
• Antistreptolysin O (ASO) Titer: Elevated ASO titers suggest recent streptococcal exposure, serving as a supportive diagnostic tool.
• Anti-DNase B: Like ASO, anti-DNase B is another marker of streptococcal infection, useful in cases where ASO titers are inconclusive.

3. Imaging Studies

Though not required for diagnosis, MRI may reveal basal ganglia hyperintensities, which can support the diagnosis if atypical symptoms are present. Imaging is typically reserved for cases where other neurological disorders are suspected or need to be ruled out.

For diagnostic guidelines, refer to the Centers for Disease Control and Prevention at https://www.cdc.gov/.

Differential Diagnosis of Sydenham’s Chorea

Several movement and psychiatric disorders can present with similar symptoms to Sydenham’s chorea, making differential diagnosis essential for appropriate management.

1. Chorea Gravidarum: This pregnancy-associated chorea is distinct in its presentation and etiology but may resemble Sydenham’s chorea in appearance.
2. Huntington’s Disease: An inherited neurodegenerative disorder presenting with chorea, but with a progressive course and adult onset.
3. Autoimmune Encephalitis: Certain types of autoimmune encephalitis may present with chorea and behavioral changes, requiring careful assessment to differentiate from Sydenham’s chorea.
4. PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections): This condition has overlapping symptoms with Sydenham’s chorea but is associated with a broader set of neuropsychiatric disturbances.

Complications of Sydenham’s Chorea

Sydenham’s chorea can lead to various complications, particularly when associated with ARF.

1. Rheumatic heart disease (RHD)

As part of ARF, Sydenham’s chorea is often associated with carditis, which can progress to RHD, a leading cause of acquired heart disease in children and young adults. This association underscores the importance of early intervention and long-term management.

2. Psychosocial and Academic Impact

The physical and behavioral symptoms of Sydenham’s chorea can lead to social stigma, emotional stress, and academic difficulties, impacting both the patient’s self-esteem and their relationships.

3. Risk of Recurrence

Recurrences are common, particularly with subsequent GAS infections. Prophylactic antibiotics are recommended to reduce this risk and prevent ARF complications.

For further information on ARF complications and RHD prevention, consult the World Heart Federation at https://www.world-heart-federation.org/.

Treatment of Sydenham’s Chorea

Management of Sydenham’s chorea includes both symptomatic treatment and preventive measures against recurrence.

1. Symptomatic Treatment

• Sedatives and Tranquilizers: Medications such as diazepam can help control involuntary movements and emotional symptoms, though they do not address the underlying disease.
• Antipsychotics: Haloperidol, risperidone, and other neuroleptics are often effective in reducing choreiform movements and behavioral symptoms.
• Immunomodulatory Therapy: In severe or treatment-resistant cases, corticosteroids or intravenous immunoglobulin (IVIG) may be considered, although their use remains controversial and is typically reserved for refractory cases.

2. Antibiotic Prophylaxis

Long-term prophylaxis with benzathine penicillin G is recommended to prevent recurrent GAS infections and subsequent ARF episodes. The duration of prophylaxis depends on individual risk factors and the presence of associated rheumatic heart disease.

3. Supportive and Behavioral Therapy

• Cognitive and Behavioral Therapy (CBT): Behavioral therapy can be beneficial in managing obsessive-compulsive symptoms and improving overall coping skills.
• Physical Therapy: Regular physical therapy may help maintain muscle strength and coordination, particularly in patients with persistent chorea or motor impairments.

For comprehensive treatment guidelines, refer to the American Academy of Neurology at https://www.aan.com/.

Long-Term Management and Prognosis

Sydenham’s chorea generally has a favorable prognosis, with most cases resolving within a few weeks to months. However, recurrence is possible, and patients with concurrent carditis or RHD may face additional health challenges. Long-term follow-up with a multidisciplinary team is recommended to monitor for recurrences, manage prophylaxis, and address any residual neurological or behavioral symptoms.

Conclusion

Sydenham’s chorea is a complex, multifaceted neurological disorder that remains clinically significant in areas with high rates of streptococcal infections and ARF. Early recognition, effective symptomatic treatment, and antibiotic prophylaxis are essential to managing this condition and reducing the risk of recurrence and complications. As our understanding of autoimmune movement disorders continues to evolve, further research into the mechanisms of Sydenham’s chorea may pave the way for more targeted therapies and improved outcomes for patients worldwide.