Chorea describes a type of involuntary movement characterized by brief, irregular, and unpredictable muscle movements. The term originates from the Greek word for “dance,” reflecting the seemingly dance-like quality these uncontrolled movements can take on. Chorea is not a disease itself, but rather a symptom that indicates an underlying medical condition.
Understanding Chorea Movement
Chorea manifests as excessive, spontaneous movements that are irregularly timed, non-repetitive, and randomly distributed across the body. These movements can vary in their intensity, ranging from subtle fidgeting and restlessness to a continuous flow of disabling, violent motions. The unpredictable nature of these jerky movements is a defining characteristic, helping to distinguish chorea from other types of involuntary movements.
These involuntary motions can affect various body parts, including the face, arms, legs, and trunk. Facial muscles might show random wrinkling of the nose or movements of the eyes, mouth, or tongue. Individuals may also have difficulty maintaining tongue protrusion, leading to a “jack-in-the-box” or “darting tongue” phenomenon.
Chorea can also interfere with voluntary actions and daily activities. For example, it can make it challenging to maintain a steady grip, sometimes described as a “milkmaid’s grip.” Walking may become unstable and dance-like, and speech and swallowing can be affected. Chorea movements are present during wakefulness but cease during sleep.
Diverse Causes of Chorea
Chorea can arise from a wide range of underlying conditions, often stemming from issues within the basal ganglia, a part of the brain that helps control movement. Overactivity of dopamine, a neurotransmitter in this brain region, is often implicated in the development of chorea. Causes are broadly categorized into genetic and acquired factors.
Genetic conditions represent a significant group of causes, with Huntington’s disease being the most recognized. This inherited neurodegenerative disorder features chorea as a prominent symptom. Other genetic causes include Wilson disease, benign hereditary chorea, and certain spinocerebellar ataxias.
Acquired causes encompass a variety of medical conditions and external factors. Autoimmune disorders, such as systemic lupus erythematosus, can lead to chorea when the immune system mistakenly attacks brain tissue. Sydenham’s chorea, common in children, is an autoimmune reaction that can occur after a Group A streptococcal infection, like strep throat or rheumatic fever.
Metabolic imbalances, such as hyperthyroidism or low calcium levels, can also induce chorea. Certain medications, including those used to treat Parkinson’s disease, antidepressants, and antipsychotics, or substances like cocaine and amphetamines, can cause chorea as a side effect. Brain injuries from stroke, tumors, or infections can also disrupt the basal ganglia’s function, leading to chorea.
Approaches to Managing Chorea
Managing chorea involves addressing the underlying cause when possible and providing symptomatic relief for the involuntary movements. If chorea is a side effect of medication, adjusting or discontinuing the offending drug can resolve the symptoms. For causes like metabolic imbalances, correcting the imbalance can alleviate chorea. In cases of Sydenham’s chorea, treating the streptococcal infection with antibiotics is a foundational step, and immune-modulating therapies may be considered for severe symptoms.
When the underlying cause is not treatable or chorea persists, symptomatic treatments focus on reducing the involuntary movements. Medications that modulate dopamine activity in the brain, such as dopamine-blocking agents, are used because chorea is associated with an overactivity of dopamine. These medications aim to restore a more balanced neurotransmitter function in the basal ganglia.
Supportive therapies play a role in managing the impact of chorea on daily life. Physical therapy can help individuals maintain mobility, balance, and coordination. Occupational therapy assists with adapting daily tasks and activities to accommodate the movements, improving functional independence. These therapies, combined with lifestyle adjustments, help individuals cope with involuntary movements and enhance their quality of life.