Introduction:
Hemichorea is a disorder related to the basal ganglia (a structure present near the center of the brain) of the central nervous system. The disease is characterized by sudden, intermittent, and involuntary (not depending upon one will) movement involving one arm and leg on the same side resulting in disability and irregular limb dancing. The disorder is caused due to dysfunction in the central nervous system. Hemichorea differs from chorea in that the movements involve one side of the limbs, and chorea involve both sides of the limbs. Hemichorea can result from mutations, stroke, trauma, infection, metabolic disease, and autoimmune disease and can interfere with speech, swallowing, gait, and posture. The disease is mainly found in diabetic patients and with weakened immune systems. Around thirty thousand people in the United States are suffering from hemichorea. The disorder is rare and worsens over time.
What Are the Causes of Hemichorea?
Hemichorea is associated with several acute and chronic causes, which include;
-
Vascular hemichorea may be due to stroke (blood vessel in the brain is damaged) and type 2 diabetes mellitus.
-
Autoimmune hemichorea includes vasculitis (inflammation of blood vessels), systemic lupus erythematosus (the body attacks its healthy cells), and paraneoplastic syndrome (cancer).
-
Drug-induced hemichorea includes alcohol, cocaine, and antiepileptic drugs like Hydantoin and Valproic acid.
-
Metabolic hemichorea includes liver diseases, diabetes mellitus, and hyperthyroidism (the thyroid gland makes excess hormones).
-
Infectious hemichorea includes Human immunodeficiency virus (HIV) and tuberculosis (disease affects the lungs).
Who Are at Risk of Hemichorea?
Hemichorea can affect any age, race, and sex, but the people aged eighty and above are more affected. A certain group of people at high risk of developing disease include.
-
Endocrine and metabolic disorders like hypoparathyroidism (parathyroid gland does not produce parathyroid hormone), hypocalcemia, hyperthyroidism (thyroid gland produces excess hormone), hypomagnesemia, and hepatic failure.
-
Untreated Streptococcus infection leads to rheumatic fever.
-
Medications like antipsychotic drugs can produce hemichorea.
-
Poisoning by mercury, carbon monoxide, or alcohol.
How Does Hemichorea Affect the Population?
Hemichorea damages the central nervous system's basal ganglia and involves inhibitory pathways. The basal ganglia consist of globus pallidus, caudate, and substantia nigra. The globus pallidus fibers convert into a white matter tract known as lenticular fasciculus and enter the thalamus. The signals from the brain to the peripheral nervous system are then sent to the muscles. The two types of pathways include.
-
The direct pathway starts with glutamate input from the cortex to the caudate nucleus and sends dopamine receptors to the globus pallidus. The globus pallidus allows the glutamate signals to the thalamus, leading to disinhibition of the thalamus and activation of the corticobulbar and corticospinal tracts.
-
The indirect pathway starts in the cortex. The activation of dopamine receptors in the globus pallidus externally sends inhibitory signals to the substantia nigra and activates the globus pallidus internally, leading to the inhibition of the thalamus. The decreased activation of the cortex leads to the inhibition of movement.
What Are the Signs and Symptoms of Hemichorea?
Hemichorea symptoms depend upon the condition causing the disorder. Hemichorea symptoms are related to the movement of the limbs that can be fast or slow. The person may have no bodily control and may appear in pain. These movements have been called dancing movements or piano-playing movements. People with this condition squeeze and release their hands as if milking, known as the milkmaid grip. Conditions associated with the disorder include;
-
Sydenham syndrome is a streptococcal infection that mainly affects adolescents and children. The syndrome can be a complication of rheumatic fever (an autoimmune disease that inflames the joints and tissues). It mainly affects the face, arms, and hands. The person will not be able to feed themselves and get dressed. The symptoms include muscle weakness, abnormal gait, impaired speech, and muscle tone.
-
Huntington’s disease leads to the breakdown of the nerve cells in the brain. Symptoms include impairment in the movement of the legs and arms. The disease is more common in adults.
-
Acanthocytosis is a rare genetic disorder. Symptoms include neurological abnormalities, abnormal arm, and leg movements, teeth grinding, drooling of saliva, difficulty swallowing, slurred speech, and pelvic thrusts.
How Can Hemichorea Be Diagnosed?
Many conditions cause hemichorea. There are several investigations and tests to diagnose hemichorea. The investigation includes.
-
Physical Examination - The doctor may watch the symptoms associated with the disease, like irregular movements confined to one side of the body, any family history of Huntington's disease, and the medications a person takes.
-
Lab Examinations - The doctor may prescribe laboratory tests in case of poisoning, neoplasms, and infectious diseases to determine abnormal mercury and copper levels.
-
Blood Test - The doctor may prescribe a blood test to check the abnormal levels of red blood cells for parathyroid and thyroid hormones. Increased red blood cells may indicate acanthocytosis.
-
Magnetic resonance imaging scan (MRI) - The doctor can prescribe MRI to check the brain activity that indicates a disease. It typically shows signal changes in the caudate and putamen of basal ganglia.
How Can Hemichorea Be Managed?
-
Hemichorea treatment depends upon the cause and severity of the illness. Hemichorea can be treated, depending on the condition, with antibiotics and antipsychotic drugs.
-
Most medications affect dopamine. Dopamine is a neurotransmitter that controls thinking and movements in the brain.
-
Antipsychotic drugs, including Fluphenazine, Olanzapine, and Haloperidol, can reduce hemichorea. Some medications that can reduce the dopamine in the brain include Tetrabenazine, and Reserpine.
-
The doctor may advise surgery if the patient does not respond to medications. Surgery does not improve hemichorea but can reduce symptoms.
-
Home care includes nonslip surfaces in the bathroom and staircase to prevent injury.
How Can Hemichorea Be Prevented?
Hemichorea cannot be prevented if associated with some disease or conditions. The disease can be prevented if it is associated with rheumatic fever by preventing sore throat in children.
Conclusion:
Hemichorea is a rare disease of the central nervous system. Treating the cause of the disease is important. Healthcare teams, including doctors and nurses, can educate people about the cause of the disease and encourage them that the disease can resolve with time. Psychologists and social workers may be consulted due to the emotional effect. The healthcare team can counsel the patient and family members to decrease their emotional stability.
