What is Sydenham Chorea (St. Vitus dance)?
Sydenham chorea, also known as St. Vitus dance, is a significant symptom of rheumatic fever, affecting up to 40% of rheumatic fever patients. This condition isn’t very common in the United States, but it’s more widespread in developing countries. It’s a disorder affecting brain function that’s thought to be caused by an autoimmune response. This process starts when group A β-hemolytic Streptococci, a type of bacteria, ‘tricks’ the body’s immune system into attacking brain cells instead.
Specifically, the body produces anti-brain cell antibodies that attack parts of the brain, particularly areas called the dorsal and ventral striatum. This attack results in the symptoms that are seen in Sydenham chorea.
Nowadays, Sydenham chorea is less frequently seen than before, and when it does happen, the symptoms are generally less severe, with fewer relapses. This reduction could be due to prompt treatment of infections caused by group A streptococci, better hygiene practices, and a decrease in the specific strain of streptococcus that causes the misdirected immune response.
In diagnosis procedures for rheumatic fever, TD Jones proposed The Jones Criteria, which included Sydenham chorea as a major diagnostic sign. A large number of rheumatic fever patients who develop Sydenham chorea also suffer from heart inflammation, known as carditis, which can lead to valvular heart disease.
What Causes Sydenham Chorea (St. Vitus dance)?
Sydenham chorea is thought to be a disorder of the immune system, usually happening after an infection caused by a type of bacteria known as group A β-Hemolytic streptococci. In response to this bacterial infection, your immune system creates special proteins called antibodies to fight it off. However, these antibodies can mistakenly attack cells in a part of the brain called the basal ganglia, particularly the striatum cells, which have a crucial role in controlling our movements. The harm and death of these cells are believed to cause symptoms of Sydenham chorea.
Risk Factors and Frequency for Sydenham Chorea (St. Vitus dance)
Sydenham chorea is a disease that typically shows up 6 to 8 weeks after a certain type of throat infection known as group A β-hemolytic streptococcal pharyngitis. It doesn’t happen following skin infections. It’s more common in females than males, at a ratio of 3 to 1. The disease primarily affects children between 5 to 18 years of age; it’s rarely seen in children younger than 5 with the highest rates seen at ages 8 to 9. Sydenham chorea affects children of all races and ethnicities. It’s a significant indicator used for the diagnosis of rheumatic fever. About 25% of patients with rheumatic fever develop this condition. However, the number of cases in North America has been dropping steadily over the past few decades, thanks to a decrease in rheumatic fever cases and better use of antibiotics.
Adult-onset Sydenham chorea is not common, and most adult cases usually come up as second-time events after an initial illness in childhood. The rate of incidence is higher in developing countries due to a bacterial infection known as β-hemolytic Streptococci and insufficient treatment of this infection, made worse by overcrowding and poor hygiene. Chorea gravidarum is a similar condition related to pregnancy. In most cases, it’s a second occurrence of Sydenham chorea, thought to be brought on by hormonal changes during pregnancy or the use of birth control pills. In such instances, symptoms often vanish soon after childbirth.
Signs and Symptoms of Sydenham Chorea (St. Vitus dance)
Sydenham chorea is a medical condition often associated with rheumatic fever, but it can also occur independently. This condition typically emerges 6-8 weeks after an infection of the throat caused by group A β-hemolytic Streptococcus bacteria or GABHS. Common features of this condition include uncontrolled movements, muscular weakness, and mental health issues. These uncontrolled movements usually affect all four limbs. Other symptoms might include problems with walking, loss of muscle control, changes in handwriting skills, and the onset of cognitive or emotional disorders. You might notice facial grimacing or tongue movements. A symptom called the “milkmaid sign,” which refers to a weak handgrip similar to the hand movement while milking a cow, is also common. Tics, or sudden, repetitive movements or sounds, are common in patients with Sydenham chorea.
Vocal tics, or sudden, repetitive vocal sounds, are reported in about 70% of patients. These are thought to be related to uncontrolled movements of the throat and voice box. Speech difficulties and reduced fluency due to muscle involvement are also common. Overall, about 70% of patients experience generalized uncontrolled movements, 30 to 35% have symptoms that affect only one side of the body, and 60% have other neurological symptoms, including difficulties with speech and writing.
Behavioural issues are also common. Anxiety and depression are prevalent, affecting 77% of patients, and obsessive-compulsive behaviours can be seen in up to 70% of patients. About 16.7% of patients meet the criteria for obsessive-compulsive disorder. Hyperactivity and attention deficit problems are present in up to 45% of patients, and some may experience psychosis during the acute phase of the illness. Conditions related to heart inflammation can occur in up to 80% of patients.
There’s a controversial syndrome known as Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS), where patients suddenly develop OCD and tics that persist regardless of treatment. In cases of “Chorea gravidarum,” uncontrolled movements start during pregnancy, but this is not a specific disease. Rheumatic fever was often the cause, suggesting a link to Sydenham’s chorea. Nowadays, due to the decrease in rheumatic fever cases, it’s not a major cause. The main mechanism is believed to be immune-mediated and often linked to underlying autoimmune issues like antiphospholipid antibody syndromes.
Another possibility is hormonal changes during pregnancy, particularly estrogen, and the use of oral contraceptives. Changes in the brain similar to those found in Sydenham’s chorea patients have been noted in these cases.
Testing for Sydenham Chorea (St. Vitus dance)
Chorea, a disorder marked by abnormal, involuntary movements, can’t be definitively diagnosed with specific tests. However, if you are suspected of having chorea, your doctor will want to conduct a detailed neurological and heart examination. They will also likely order routine blood tests. These will likely include a complete blood count, liver function test, complete metabolic panel, and tests to check your B12 and thyroid-stimulating hormone levels.
Two other key tests your doctor might order are Antistreptolysin-O titer (ASOT) and anti-DNAse B titers, which can be raised for up to one year following a throat infection caused by the group A streptococcus bacteria. However, other tests like C-reactive protein and erythrocyte sedimentation rates (which are used to measure inflammation) might not be very useful. This is because there is typically a delay between the initial throat infection and the onset of chorea, so these tests may not show anything unusual.
If you have chorea, there’s a high chance you might have heart disease as well, as this is the case for up to 80% of Sydenham chorea patients. Therefore, you might also need to have an echocardiogram, which is a type of ultrasound scan that looks at the heart and nearby blood vessels.
In terms of imaging tests for your brain, CT and MRI scans are typically normal for people with chorea, although sometimes there may be changes seen in the basal ganglia, which is a part of the brain. Getting an MRI scan in children can be more challenging due to the need for sedation, and should be decided on an individual basis. If you’re an adult newly diagnosed with chorea, it’s more likely that you may have a problem in a part of your brain called the basal ganglia, especially in an area known as the striatum. In this case, a brain MRI would be strongly recommended.
Sometimes, PET scans and SPECT imaging may show higher than normal rates of metabolism and blood flow in the basal ganglia, while other types of chorea may show lower than normal rates. However, these tests are usually only used in research situations.
Treatment Options for Sydenham Chorea (St. Vitus dance)
In the past, this disorder was viewed as a mild illness that would usually disappear in a few months. More recently, however, studies discovered that many patients experienced chorea, a neurological disorder characterized by jerky movements, for up to two years. Furthermore, about half of the patients may have recurrent movement disorders, even with preventive treatment. Some of these recurrences are not linked to bacterial infection or presence of specific antibodies.
One serious concern for these patients is the risk of developing heart valve problems, which could be a part of another disorder called rheumatic fever. There’s a strong connection established between chorea and the development of inflammation or diseases of the heart muscles or valves.
Sydenham chorea treatment traditionally falls into three categories: preventive penicillin treatment to fight and prevent infection, symptom relief therapies using medications typically used for psychosis or seizures, and medicines that moderate the body’s immune response, such as steroids, intravenous immunoglobulin (medications used to treat the immune system), and plasma exchange (a procedure that removes and replaces the plasma in blood).
Preventing Sydenham chorea by treating throat infections caused by a particular strain of streptococcal bacteria is particularly effective. It can also lower the chance of developing rheumatic heart disease. Once Sydenham chorea is diagnosed, additional protective antibiotic treatment may help decrease the risk of neurological and heart issues with future streptococcal infections. The World Health Organization recommends the preventive use of these antibiotics for those under the age of 21.
Unlike prevention, symptomatic treatment options haven’t been thoroughly studied. Typically, a medication called valproic acid has been used. It’s started at a small dose and gradually increased until symptoms decrease. However, this medication takes time to work, and usually two weeks are allowed before it’s considered ineffective. If valproic acid doesn’t work, another type of medication is used. This could include drugs like risperidone or tetrabenazine, but these also come with their own potential risk of uncontrollable body movements. It should be noted that suppressing the immune system has not proven effective.
In severe and difficult-to-treat cases of Sydenham chorea, medications that affect the immune system may be considered. Steroids often provide benefits, but data on the effects of other treatments, such as intravenous immunoglobulin and plasma exchange, isn’t as extensive.
What else can Sydenham Chorea (St. Vitus dance) be?
Sydenham chorea, a type of movement disorder, needs to be differentiated from other conditions that can cause similar symptoms. These conditions can be related to autoimmune diseases, exposure to toxins, issues with blood vessels (vascular), or inherited genetic conditions. Identifying how fast the symptoms started can help with this process. So if the symptoms have appeared suddenly or within a short time, it might be due to a toxic or vascular cause. But if the symptoms have appeared gradually over time, it might be a genetic condition. Usually, but not always, there’s a family history of the same problem with these genetic conditions.
Among the children, the sudden start of chorea (movement disorder) is most commonly due to Sydenham chorea itself which is a sign of acute rheumatic fever, or due to a disease called systemic lupus erythematosus (SLE), especially when there’s a presence of a special type of antibody in the blood called antiphospholipid antibody.
Also, physicians need to consider ruling out the following conditions:
- Huntington’s disease
- Acute stroke that affects a part of the brain called the basal ganglia
- Side effects from certain medications, including drugs that affect dopamine, a chemical messenger in the brain
- Low blood sugar (Hypoglycemia) and high blood sugar without ketones (nonketotic hyperglycemia)
- Lyme disease
- Multiple system atrophy (condition that affects your body’s involuntary functions)
- Neuroacanthocytosis (a group of rare, neurological disorders)
- Neuronal ceroid Lipofuscinosis (a group of inherited disorders that affects the nervous system)
- Olivopontocerebellar atrophy
Possible Complications When Diagnosed with Sydenham Chorea (St. Vitus dance)
Most people generally recover completely within a span of 3 to 6 months. However, a few children might still experience symptoms for up to 2 years. Moreover, symptoms can reoccur later in life, particularly in individuals assigned female at birth (AFAB) who either take estrogen, use birth control pills, or become pregnant.
Recovery and Possible Recurrence:
- Most people recover fully within 3 to 6 months
- A small number of children may have symptoms for up to 2 years
- Symptoms can return later in life
- Possibility of recurrence in individuals AFAB who take estrogen or birth control pills or get pregnant
