OVERVIEW

What is hemiballismus?

Hemiballismus is not a disease but a symptom. It is an involuntary movement where patients, while fully conscious, cannot control their motions. The main manifestation is violent, flinging movements on one side of the body. It is usually caused by lesions in the pathway from the striatum to the subthalamic nucleus, with stroke being the most common cause.

Is hemiballismus clinically common?

It is extremely rare—500 times rarer than Parkinson's disease.

SYMPTOMS

What are the manifestations of hemiballismus?

Patients mainly exhibit violent throwing movements on one side of the body, with large amplitude and strong force, predominantly affecting proximal limbs. Severe cases may lead to disability.

CAUSES

What are the causes of hemiballismus?

It is primarily caused by lesions in the contralateral subthalamic nucleus or the pathways transmitting signals from the striatum to the subthalamic nucleus. Therefore, any disease that may lead to lesions in this area can result in hemiballismus:

• The most common cause is stroke. Other cerebrovascular diseases such as traumatic brain injury, vasculitis, or brain tumors may also produce this symptom. Amyotrophic lateral sclerosis (ALS) may also affect the subthalamic nucleus region, leading to hemiballismus.

• Recent reports indicate that hemiballismus can also be caused by non-ketotic hyperglycemia or HIV infection in hemiplegic patients. Currently, hemiballismus induced by non-ketotic hyperglycemia is referred to as Hemichorea-Hemiballismus syndrome, primarily due to changes in the contralateral subthalamic nucleus caused by hyperglycemia or hyperviscosity. Typically, the symptoms disappear after correcting the hyperglycemia. In hemiplegic patients infected with HIV, immune system deficiencies may lead to cerebral toxoplasmosis, which can cause basal ganglia lesions and result in hemiballismus.

Is hemiballismus hereditary?

No.

Is hemiballismus contagious?

In most cases, no. However, if it is caused by HIV infection, it may be contagious.

DIAGNOSIS

How is hemiballismus diagnosed?

Doctors can usually diagnose it based on clinical manifestations.

What tests are needed for hemiballismus?

• Neurological examination: Checks for abnormalities in muscle strength, muscle tone, tendon reflexes, etc.;

• Blood tests: Routine blood tests to check for infections, blood sugar levels, etc.;

• Lumbar puncture: Determines whether there is infectious encephalitis. A needle is inserted into the lower back to extract cerebrospinal fluid for testing, which can identify the specific bacterial infection and also relieve symptoms like headaches and vomiting. This test is crucial for diagnosing bacterial meningitis but is invasive, requiring patient and family consent. The patient must remain still during the procedure, and family members may need to provide comfort. After the puncture, the patient must lie flat without a pillow for a period of time.

• Brain imaging: CT or MRI scans to check for abnormal brain damage.

What diseases should hemiballismus be differentiated from?

Hemiballismus is easily confused with chorea, but chorea primarily affects the distal limbs, while hemiballismus mainly involves the proximal limbs. However, sometimes hemiballismus and chorea may coexist in the same patient, in which case it is classified as chorea.

TREATMENT

Which department should I visit for hemiballismus?

Neurology.

Is it necessary to see a doctor for hemiballismus?

Yes.

Can hemiballismus resolve on its own?

It depends. For example, cases caused by hyperglycemia may improve through the body's self-regulation when symptoms are mild. Hemiballismus caused by minor stroke may also resolve spontaneously.

How is hemiballismus treated?

The most crucial step is identifying and treating the underlying cause. For stroke, antithrombotic or thrombolytic therapy is given; for vasculitis, antihistamines or steroids; for tumors, surgical removal or radiation/chemotherapy; for nonketotic hyperglycemia, glucose-lowering treatment. HIV-related cases may prioritize immune system treatment over direct HIV therapy.
For cases with unknown or untreatable causes (e.g., ALS-induced hemiballismus), symptomatic treatment like dopamine blockers (haloperidol, chlorpromazine) or antipsychotics may help. Pallidotomy surgery is an option for severe, drug-resistant cases.

Can hemiballismus be cured completely?

Some patients have good prognosis and can achieve complete recovery.

DIET & LIFESTYLE

What should family members of hemiballismus patients pay attention to when caring for hemiballismus patients?

• Pay attention to a healthy diet and supplement protein in terms of diet.

• In daily life, when the patient has an episode, it is necessary to prevent harm to others and provide timely psychological comfort.

PREVENTION

Can Hemiballismus Be Prevented? How to Prevent It?

Prevention generally focuses on cerebrovascular diseases, such as adopting a low-salt, low-fat diet, maintaining regular exercise, and controlling high-risk factors like blood pressure, blood sugar, and cholesterol. Elderly patients, based on their individual risks, may take small doses of aspirin and statins to prevent ischemic stroke.