Hemiballismus is a separate type of hyperkinesis caused by the lesion of the subthalamic body of Lewis. It is characterized by typical violent high-amplitude movements covering the proximal extremities of one half of the body. It is diagnosed according to the neurological status, brain tomography, analysis of cerebrospinal fluid. Drug treatment is carried out with dopamine receptor blockers, gabaergic agents against the background of therapy of causal pathology. In resistant cases, neurosurgical treatment (thalamotomy, pallidotomy) is possible.
G25.5 Other types of chorea
The medical term “ballism” comes from the Greek “ballismos” – throwing, denotes sharp involuntary throwing motor acts. Ballistic hyperkinesis is most often observed in the upper and lower extremities of one half of the body. Such a one-sided variant of ballism was called hemiballismus. Involvement in hyperkinesis of all limbs is indicated by the term “paraballism”, one arm or leg — by the term “monoballism”, but these conditions are diagnosed much less often. According to statistics, hemiballismus accounts for 1.7% of all motor disorders, is widespread everywhere, has no gender preferences.
Hyperkinesis develops due to dysfunction of the subthalamic basal ganglion, called the Lewis nucleus in neurology. The etiofactors of the lesion of the Lewis body in most cases are acute disorders of cerebral circulation, which occur as a result of angioma or arteriovenous malformation of the vessels supplying the subthalamic nucleus area. Other reasons are less common. All etiological factors of hemiballismus are divided into:
- Vascular: ischemic, hemorrhagic strokes. A violation of the blood supply to the subthalamic ganglion causes hypoxia of its neurons. Oxygen starvation adversely affects the function of nerve cells, leading to their death.
- Dysmetabolic: hyperglycemia. Transient hemiballismus is observed in elderly patients with type 2 diabetes mellitus with insufficient action of hypoglycemic drugs. Increased blood glucose disrupts metabolic processes in ganglion cells, leading to its dysfunction.
- Traumatic: traumatic brain injuries, neurosurgical interventions. Hemiballismus develops as a result of direct damage to the structures of the subthalamic nucleus, its compression by the resulting posttraumatic hematoma.
- Tumor: intracranial formations localized in the subthalamic region. The lesion of the Lewis body occurs as a result of the germination of tumor tissue into it, the compression of neurons by the neoplasm increasing in volume.
- Infectious: HIV-associated neuroinfections, brain abscess, herpetic encephalitis. Infectious agents provoke the development of an inflammatory reaction with the appearance of edema, infiltration, and microcirculatory disorders. These processes entail dysfunction of the Lewis nucleus, which causes hemiballismus.
- Inflammatory: collagenoses, antiphospholipid syndrome. These diseases are accompanied by the production of antibodies to the body’s own tissues. As a result, systemic autoimmune inflammation occurs, including those affecting the basal ganglia, which causes a violation of the functioning of the subthalamic nucleus.
- Medications. Some medications (levodopa pharmaceuticals, contraceptives) provoke changes in the neurotransmitter interactions of various brain structures. The consequence is the dysfunction of the extrapyramidal system, which has a regulating effect on the sphere of arbitrary movements.
Control and adjustment of the accuracy and direction of movements is a complex mechanism of coordinated work of the cortex and subcortical structures of the brain. Normally, the Lewis body has an activating effect on the pale ball, which has an inhibitory effect on the nerve cells of the ventrolateral thalamic nucleus. The neurons of this nucleus are connected to the cerebral cortex through the ascending thalamo-cortical tract. Consequently, the defeat of the subthalamic nucleus leads to the disinhibition of thalamo-cortical relationships, which is the pathophysiological basis of ballism. Since the motor pathways intersect, hemiballismus appears contralateral to the lesion. According to some reports, the clinical manifestation is caused by a lesion of more than 20% of the Lewis body.
The clinic is based on large-scale violent movements in the extremities of the half of the body opposite to the localization of the affected ganglion. Motor acts are of a sudden arrhythmic nature, more pronounced in the proximal parts (shoulders, hips), may have a rotational component. Patients complain about the inability to control or reduce the manifestations of hyperkinesis. Increased movements are observed with excitement, emotions, mental stress. Typically, the complete disappearance of involuntary movements in a dream.
In half of the cases, hemiballismus is combined with involuntary contractions of facial muscles, which leads to the appearance of grimaces, speech disorders (dysarthria), swallowing. According to the location and size of the pathological focus, hemiballismus is accompanied by a decrease in muscle strength (hemiparesis), sensory disorders (hemihypesthesia), cognitive disorders, changes in muscle tone.
The nature of the course of ballism depends on its etiology. In the case of a stroke, an acute manifestation is noted, followed by a slow regression of hyperkinesis. Hemiballismus of tumor, infectious genesis is characterized by a gradual debut with further aggravation of motor disorders. Systemic autoimmune lesions are accompanied by recurrent attacks of hemiballismus, localized in one or the other half of the body.
Involuntary movements with hemiballismus have a large amplitude, accompanied by the impact of limbs on various surrounding objects. Often there is an injury to the patient: bruises, fractures of the arm, leg. Unilateral localization of uncontrolled movements provokes loss of balance and falling of the patient, which also leads to mechanical injuries. Traumatism is the most frequent, repeated complication of ballism, often requiring medical care.
Involuntary motor acts characterizing hemiballismus have a pathognomonic pattern, which makes them easy to diagnose. However, hyperkinesis is only a syndrome of the underlying disease, the definition of which is the ultimate goal of diagnosis. The list of studies necessary for the final diagnosis includes:
- Neurological examination. During the study, a neurologist evaluates muscle strength, tone, intensity and symmetry of reflexes, sensitivity level, coordination, and the state of the cognitive sphere. The nature of the identified concomitant focal symptoms suggests localization of the lesion.
- Cerebral tomography. CT of the brain is more informative in the diagnosis of traumatic injuries and hematomas. MRI of the brain better visualizes tumor processes, inflammatory changes, ischemic zones.
- Examination of cerebrospinal fluid. The material is taken by lumbar puncture. The analysis allows you to identify inflammatory changes, tumor cells, infectious agents, the presence of blood during hemorrhage.
Differential diagnosis is performed with other types of hyperkinesis: chorea, athetosis. Choreic hyperkinesis is characterized by a smaller amplitude of violent movements, localization in the distal extremities. Athetosis is characterized by slow movements mainly in the hands.
Therapy is carried out against the background of treatment of the underlying disease. Taking into account the etiology, vascular, neuroprotective, antibacterial, antiviral, immunosuppressive drugs are used. In the case of volumetric education, the issue of neurosurgical removal is considered. Pathogenetic treatment of hemiballismus includes the following methods:
- Pharmacotherapy with neuroleptics blocking dopamine receptors (haloperidol, tiaprid). The drugs reduce the manifestations of hemiballismus by blocking the excessive activation of the thalamo-cortical pathway.
- Appointment of GABA agonists (valproates, clonazepam). Hyperkinesis is stopped by potentiating the action of gamma-aminobutyric acid— the main inhibitory neurotransmitter of the central nervous system.
- Stereotactic destruction of basal ganglia. Indications for surgery are severe cases resistant to pharmacotherapy. The decision on the expediency of surgical intervention is made jointly with the neurosurgeon. Thalamotomy is performed — destruction of the ventrolateral thalamic ganglion, pallidotomy — destruction of the pale globe.
- Electrostimulation of the ventrolateral nucleus. Electrical blocking stimuli are carried out using implanted electrodes, reduce excitatory thalamo-cortical impulses and associated hemiballismus.
Of no small importance in the treatment process is the prevention of injury to the patient. For this purpose, it is recommended to equip the patient’s room in a special way, close the protruding parts of the furniture with foam, if necessary, fix the limb.
Prognosis and prevention
The prognostic value is the nature of the underlying disease, the age of the patient, the time of the beginning of qualified treatment. Hemiballismus after a stroke, injury, infection can completely regress against the background of effective drug therapy. A number of patients have persistent residual hyperkinesis that requires constant treatment. The most difficult prognosis is hemiballismus of tumor genesis, since radical excision of the tumor is associated with the removal of the tissues of the subthalamic nucleus. There is no specific prevention. Preventive measures include timely treatment of cerebrovascular, infectious, autoimmune diseases, prevention of TBI, hyperglycemic conditions.