Hyperkinesis: types and causes

Hyperkinesias are excessive involuntary movements (often with a semi-voluntary component) that include tremor, dystonia, chorea/ballismus, myoclonus, tics, stereotypies, and some "functional" (previously psychogenic) movement phenotypes. These are clinical syndromes, not diagnoses; a definitive diagnosis requires a combination of phenomenology, chronology, and examination data. A modern approach divides hyperkinesias into "jerk" (myoclonus, tics, chorea) and "non-jerk" (tremor, dystonia), which simplifies initial assessment. [1]

Why is this important? Disorders affect daily functioning (writing, eating, sleeping), mental health, and social adaptation; some forms (for example, chorea in Huntington's disease) are progressive and require a long-term management strategy. A number of hyperkinesias are reversible when the cause is eliminated: Wilson's disease, drug-induced forms, autoimmune chorea, functional disorders—here early diagnosis is essential. [2]

Finally, in ICD-11, tics have been moved from the mental disorders section to the neurological movement disorders section (8A05), better reflecting their neurobiology and facilitating patient care. This isn't just bureaucracy: both care pathways and research priorities have changed. [3]

Code according to ICD-10 and ICD-11

In ICD-10, hyperkinesias are "scattered" across sections: tremor and myoclonus - in G25, dystonia - in G24, chorea (except Huntington's disease) - in G25.5, dosage forms - with the note "drug-induced", tics - in F95, hemifacial spasm - in G51.3. Huntington's disease is coded separately (G10). This is important to take into account when compiling statistics and routes. [4]

ICD-11 contains a single block, "Movement disorders," 8A00-8A0Z, with subblocks: choreic (8A01), dystonic (8A02), tremor (8A04), tics (8A05), myoclonus (8A06), etc. The system supports post-coordination (clarification of cause, topic, time of onset). This reflects modern clinical logic: phenotype + etiology. [5]

Table 1. Common hyperkinesias and codes (ICD-10 ↔ ICD-11)

Phenotype	ICD-10	ICD-11
Essential tremor	G25.0	8A04.1 "Essential tremor or related tremors"
Myoclonus	G25.3	8A06.* "Myoclonic disorders"
Chorea (not Huntington's)	G25.5 / G25.4 (drug-inducing)	8A01.* "Chorean disorders"
Dystonia	G24.*	8A02.* "Dystonic disorders"
Tics/Tourette syndrome	F95.*	8A05.* "Tic disorders"
Hemifacial spasm	G51.3	8A07.1x (as “specified movement disorders”, by localization) [6]

Epidemiology

Essential tremor is the most common hyperkinesis: ≈0.32% of the general population, ranging from 0.04% in those aged <20 years to 2.87% in those ≥80 years; in people ≥65 years, some meta-analyses show ≈5.79%. The prevalence increases significantly with age. [7]

Idiopathic/isolated dystonias are less common: the overall estimate is ≈16.4 per 100,000 (with wide variability in study design; service registries yield higher numbers). Some population-based studies in recent years suggest that the incidence and prevalence may be underestimated. [8]

Tics are common in children and adolescents: for Tourette syndrome, the global prevalence is ≈0.5% (95% CI 0.3-0.8%), and according to public health data, tic disorders in general reach 1 in 162 children. In adulthood, pronounced tics are less common. [9]

For chorea, the etiology is important. For Huntington's disease, the diagnosed prevalence in North America and Europe ranges from 8-9 per 100,000, and the global prevalence is approximately 4.9 per 100,000, with regional "hot spots." [10]

Table 2. Approximate prevalence figures

Phenotype	Prevalence assessment	Sources
Essential tremor	0.32% (general population); up to 2.87% in those ≥80 years; ≈5.79% in those ≥65 years	[11]
Dystonia (isolated)	≈16.4 per 100,000	[12]
Tourette syndrome	≈0.5% in children; total tic disorders up to 0.6%+	[13]
Huntington's disease (chorea)	≈4.9 per 100,000 globally; 8-9 per 100,000 in North America/Europe	[14]

Reasons

Causes are conventionally divided into primary (idiopathic/genetic) and secondary (symptomatic). Primary causes include essential tremor, some dystonias (including inherited forms), Tourette syndrome, benign hereditary chorea, and others. [15]

Secondary forms are caused by medications (neuroleptics, antiemetics, antidepressants, etc.), metabolic and systemic disorders (Wilson's disease, autoimmune diseases - systemic lupus erythematosus and antiphospholipid syndrome with chorea), infections (Sydenham's chorea), as well as structural damage to the central nervous system. [16]

For myoclonus, the spectrum of etiologies ranges from cortical hyperexcitability (post-hypoxic, epileptic) to segmental and peripheral variants; therapeutic tactics are based on this neurophysiological typing. [17]

Table 3. Etiological "boxes" and examples

Group	Examples	Clinical clues
Idiopathic/genetic	Essential tremor; primary dystonias; Huntington's disease; benign hereditary chorea	Family history, early onset
Medicinal	Neuroleptics (dyskinesia, akathisia, tremor), antiemetics, antidepressants	Relationship with dose initiation/change
Metabolic	Wilson's disease	CF rings, low ceruloplasmin/high urinary copper excretion
Autoimmune	SLE/APS-chorea; paraneoplastic	Antibodies, systemic manifestations
Infectious	Sydenham's chorea	Recent streptococcal infection, carditis in children [18]

Risk factors

A family history increases the risk of essential tremor, primary dystonia, and tic disorders. Age is a major driver of tremor. For chorea, the presence of the abnormal HTT allele (in Huntington's disease) is a significant risk factor. [19]

Drug triggers are important in patients receiving neuroleptics/antiemetics/serotonergic drugs; the likelihood increases with high doses and rapid titration.[20]

Autoimmune factors (SLE, antiphospholipid antibodies) are associated with the risk of chorea; in children, a recent streptococcal infection (Sydenham). Metabolic factors (copper in Wilson's disease) are important in young people. [21]

Pathogenesis

The basal ganglia and cerebellar-thalamo-cortical circuits are key nodes. In hyperkinesias, the inhibition/excitation balance in the circuits is disrupted, leading to excessive motor firing and loss of movement "filtration." Cerebellar networks are particularly important in tremors, the striatum in choreas, and sensorimotor integration networks in dystonias. [22]

Myoclonus is more often associated with cortical hyperexcitability and abnormal synchrony of corticospinal discharges; hence the high effectiveness of antiepileptic drugs that reduce cortical excitability. [23]

Tics are the result of dysfunction of the cortico-striatal-thalamic circuits with disruption of sensorimotor “pre-sensations” (premonitory urges), which explains the effectiveness of behavioral retraining techniques (habit reversal). [24]

Symptoms

Tremor is a rhythmic oscillation of a body segment; manifestations depend on the context (rest, posture, action). Dystonia is sustained/repetitive muscle contractions with torsional postures and patterns of "task-specific" triggers (e.g., writing cramp). Chorea/ballismus is arrhythmic, "dancing" throwing movements. Myoclonus is brief "twitching" movements. Tics are sudden, repetitive movements/vocalizations, usually suppressed for a short time at the cost of increasing discomfort. [25]

Functional movement disorders mimic organic ones, but have positive diagnostic features (variability, distractibility, tremor “entrainment”, etc.). It is important to recognize them, since the treatment is different. [26]

Table 4. “Jerking” vs. “non-jerk” hyperkinesias (for primary sorting)

Group	Phenotypes	Tips
Jerks	Myoclonus, tics, chorea/ballismus	Irregularity, explosive/salve movements
Not jerky	Tremor, dystonia	Rhythmia (tremor), postural spasms (dystonia)
Mixed	Essential tremor with myoclonus; dystonic tremor	Video assessment/neurophysiology needed [27]

Classification, forms and stages

1. By phenomenology: tremor, dystonia, chorea/ballismus, myoclonus, tics, stereotypies, functional. This is the "what we see" axis. 2) By etiology: primary/secondary, genetic/symptomatic. This is the "why" axis. 3) By time: acute/subacute (e.g., drug-induced, post-infectious), chronic/progressive (e.g., Huntington's disease). [28]

In ICD-11, blocks 8A01–8A06 reflect the phenomenology (chorea, dystonia, tremor, tics, myoclonus); further clarification of the cause and topics is added by post-coordination. Functional phenotypes are identified by separate codes within the corresponding blocks (e.g., "functional tremor"). [29]

Complications and consequences

Hyperkinesias impair quality of life, leading to social avoidance, depression, and anxiety; severe dystonia and chorea increase the risk of injury and falls. Essential tremor and tics have been shown to impact self-care, learning, and work. [30]

In Huntington's disease, cognitive and behavioral impairments develop over time. Long-term drug-induced hyperkinesias (e.g., dyskinesia) can become persistent if therapy is not adjusted. [31]

When to see a doctor

• Urgent: acute hyperkinesias, especially with fever, confusion, focal symptoms; chorea in a child; sharp increase after a new medication.
• In the coming days: progressive tremor/dystonia, tics interfering with school/work; new involuntary movements in young people (rule out Wilson's disease).
• Planned: chronic symptom complexes with moderate impact on life - for selection of therapy and rehabilitation. [32]

Table 5. "Red Flags"

Situation	What are we afraid of?	The first step
Acute onset of chorea in a child	Sydenham/autoimmune chorea	Streptococcal tests, APL antibodies; neurologist/cardiologist
Adolescent/young person with mixed hyperkinesias	Wilson's disease	Slit-lamp (KF-rings), ceruloplasmin, 24-hour copper in urine
Hemifacial spasm, increasing	Neurovascular conflict	MRI/angio-MRI; consultation on botulinum toxin injections/MVD
Onset after a new drug	Drug-induced	Revision of the scheme, cancellation/replacement of the provocateur [33]

Diagnostics

Step 1. Phenomenology + video. Determine what we're looking at: tremor/dystonia/chorea/myoclonus/tics. Video with standard tests helps capture the frequency of tremors, the suppressibility of tics, and the nature of twitching. The starting axis is "what we see." [34]

Step 2. Chronology and medications. When did it start? Were there infections (tonsillitis), new medications (neuroleptics, antiemetics, antidepressants)? Acute onset suggests a secondary cause; a connection with dosage suggests a drug-related cause. [35]

Step 3. Basic tests. General clinical tests, TSH (tremor), ferritin as indicated; if onset is at a young age, to exclude Wilson's disease: ceruloplasmin, 24-hour urinary copper, slit lamp (KF rings). In case of chorea - APL antibodies/SLE screening. [36]

Step 4. Neuroimaging. MRI of the brain is indicated in cases of atypical presentation, asymmetry, rapid progression, late onset, or suspected structural cause. For hemifacial spasm, MRI/angio-MRI of the cerebellopontine angle is indicated. [37]

Step 5. Neurophysiology. For myoclonus – EEG+EMG, “jerk-locked averaging” to confirm cortical origin; for tremor – accelerometry/EMG for frequency and pattern; for functional tremor – distractibility/entrainment tests. [38]

Step 6. Genetics/immunology - as indicated. If Huntington's disease is suspected, the HTT test; for rare chorea/dystonia, targeted panels. For autoimmune chorea, an antibody profile and treatment of the underlying disease. [39]

Table 6. Mini-algorithm for laboratory diagnostics

Phenotype	What do we exclude first?	Tests
Chorea in a child	Sydenham/SCV/AFS	ASL-O/streptococcal antibodies; ANA, APL panel
Young with mixed hyperkinesias	Wilson's disease	Ceruloplasmin, 24-hour copper, slit lamp
"New" tremor	Thyrotoxicosis, drug-induced	TSH/free T4; drug history
Myoclonus	Epileptic/cortical	EEG+EMG, sometimes MRI [40]

Differential diagnosis

Tremor vs. myoclonus. Tremor is rhythmic; myoclonus is brief, arrhythmic "bursts." EMG/accelerometry quickly differentiates the phenotypes. [41]

Dystonic tremor vs. essential tremor. Dystonic tremor is irregular, asymmetrical, often with "sensory tricks." Essential tremor is more regular, bilateral, and occurs during action/maintenance. [42]

Chorea vs. tics. Tics can be suppressed by volitional effort and are preceded by a "pushing" sensation; chorea is an unsuppressed, arrhythmic movement without a deliberate component. [43]

Functional hyperkinesias are diagnosed based on positive features (variability, distractibility, frequency/amplitude instability) rather than by exclusion. [44]

Treatment

The basic principle is to treat the underlying cause. For drug-induced forms, the regimen is reviewed: the causative agent is discontinued or reduced, and alternatives are selected. For autoimmune chorea, the underlying disease is treated (steroids/immunoglobulins as indicated). For Wilson's disease, anti-copper therapy is prescribed, which can significantly reverse the course of hyperkinesis. [45]

Essential tremor: Propranolol and primidone remain first-line treatments (AAN level of evidence). In cases of insufficient response, topiramate, gabapentin, and benzodiazepines are considered in selected patients. For drug-refractory tremor, deep brain stimulation (DBS) of the VIM nucleus or MR-guided focused ultrasound (MRgFUS) are considered: both techniques reduce tremor but have different risk profiles and availability. [46]

Tremor surgery, details: DBS has been shown to be durable (tremor reduction of approximately 50-65% over 12 months, with potential for further reduction over time); bilateral stepwise management is possible. MRgFUS is a unilateral ablation (according to NICE, to be used under special quality control and informed consent conditions); the effect is rapid, but not reversible; the choice of technique is discussed in consultation. [47]

Dystonias: for focal dystonias (botulinum toxin therapy is the first-line method) with injections into the affected muscles according to dosage charts; for cervical/blepharospasm, this is the "gold standard" and is well tolerated. For generalized and severe forms, anticholinergics (trihexyphenidyl), baclofen, and clonazepam are used; in refractory cases, DBS of the globus pallidus internus (GPi) is used. Regular rehabilitation and "sensory tricks" increase effectiveness. [48]

Chorea (including in Huntington's disease): key drugs are VMAT2 inhibitors (tetrabenazine, deutetrabenazine), which reduce dopamine release in the synapse. Atypical antipsychotics are helpful in some cases, but they can increase hypokinesia/metabolic risks—balancing benefits and harms. Practical guidelines confirm the clinical benefit of VMAT2 inhibitors; deutetrabenazine is available in extended-release forms. Monitoring for depression/suicidality is necessary. [49]

Tics/Tourette's syndrome: First-line therapy after psychoeducation is a comprehensive behavioral intervention for tics (CBIT/HRT) or exposure and response prevention (ERP), including telemedicine formats. Medications include guanfacine/clonidine (especially for ADHD), aripiprazole/risperidone, and tetrabenazine, depending on the indication and comorbidity profile. The choice is made based on the patient's priorities (tic reduction vs. side effects). [50]

Myoclonus: treatment depends on the neurophysiological type. For cortical myoclonus, levetiracetam, valproate, and clonazepam are used; for segmental/focal forms, botulinum toxin injections are helpful. Combination therapy and dose titration under EEG/EMG and clinical monitoring are often required. [51]

Hemifacial spasm: Botulinum toxin injections provide clinical improvement in approximately 73-98% of patients, with effects lasting approximately 12-20 weeks and being safe. Microvascular decompression (MVD) is the only potentially curative method, with spasm-free rates of approximately 80-95% (in different series and follow-up periods). The choice between Botox and surgery depends on age, comorbidities, preferences, and MRI anatomy of the affected area. [52]

Functional hyperkinesias: the basis is an explanatory model and physiotherapy with a focus on movement retraining, cognitive-behavioral approaches; medications are traditionally of little use. It is important to identify positive diagnostic features, which increases the confidence in the treatment plan and prognosis. [53]

Rehabilitation and lifestyle: occupational therapy, targeted skill training (writing, nutrition), adaptive devices, sleep hygiene, stimulant restriction, stress management. These aren't just "little things"—over the long term, they maintain functionality and reduce the need for escalating drug therapy. [54]

Table 7. Pharmaco- and procedural options (very briefly)

Phenotype	First line	Alternatives/procedures
Essential tremor	Propranolol, primidone	DBS VIM, MRgFUS; topiramate, gabapentin
Dystonia (focal)	Botulinum therapy	Systemic: trihexyphenidyl, baclofen; DBS GPi
Chorea (Huntington)	Tetra/deutetrabenazine	Atypical Antipsychotics (with an eye on risks)
Tiki	CBIT/HRT, ERP	Guanfacine/clonidine, aripiprazole/risperidone
Myoclonus	Levetiracetam, valproate, clonazepam	Botulinum toxin therapy for focal; combination
Hemifacial spasm	Botulinum therapy	Microvascular decompression [55]

Prevention

Avoid unnecessary use of dopamine blockers and high doses, titrate slowly, and monitor for extrapyramidal side effects. For tics, early CBIT training and family psychoeducation are recommended. Prevention of rheumatic fever and control of streptococcal infections reduce the risk of Sydenham's chorea. Regular physical activity, sleep, and anxiety management reduce the severity of a number of phenotypes. [56]

Forecast

The prognosis depends on the cause. Medication-induced and functional hyperkinesias are often reversible with the right strategy. Essential tremor typically progresses slowly, but modern interventions can maintain function. Dystonias respond well to botulinum therapy; in Huntington's disease, the prognosis is determined by neurodegeneration, but chorea control improves daily functioning. [57]

FAQ

Is it tremor or myoclonus?
Tremor is rhythmic; myoclonus is short, irregular "jerks." Home video and EMG/accelerometry are sometimes helpful. [58]

Is it true that tics are “mental”?
No. In ICD-11, tics are neurological movement disorders (8A05), and the first line of treatment is CBIT/ERP behavioral therapy. [59]

When to consider DBS or MRgFUS for tremor?
When first-line drugs fail/are intolerable. DBS is reversible and adjustable; MRgFUS is a single-use ablation, usually unilateral, under specific quality control conditions according to NICE. [60]

Is hemifacial spasm better treated with injections or "surgery"?
Botulinum toxin injections are 70-98% effective and suitable for most patients. MVD is the only method with a cure rate of 80-95%, but it involves neurosurgery—an individual decision must be made after an MRI and consultation. [61]

Additional tables

Table 8. Profile of instrumental methods

Method	For what	In what cases
MRI/angio-MRI	We are looking for a structural cause/conflict	Hemifacial spasm, asymmetry, acute onset
EEG+EMG (synchronization)	Typification of myoclonus	Suspected cortical myoclonus
Accelerometry/EMG	Tremor frequency/pattern	Differentiation of tremor phenotypes
Immunopanels	Autoimmune chorea	Subacute onset, systemic signs
Metabolic screening	Wilson's disease	Young age, mixed hyperkinesias [62]

Table 9. ICD-11: Phenomenology - Level 1

Block	Content	Notes
8A01	Choreic disorders	Including hemiballismus
8A02	Dystonic disorders	Primary, secondary, paroxysmal, functional
8A04	Tremor-related disorders	Including functional tremor
8A05	Tic disorders	Transferred to neurology from ICD-10
8A06	Myoclonic disorders	Typing by topic/neurophysiology [63]

Table 10. ICD-10 codes that are frequently needed in the discharge summary

Situation	Code
Essential tremor	G25.0
Myoclonus	G25.3
Dystonia (general category)	G24.*
Other chorea/drug-induced chorea	G25.5 / G25.4
Tics/Tourette syndrome	F95.*
Hemifacial spasm	G51.3 [64]