What are the causes of uncontrolled movement of the upper extremities?

Causes of Uncontrolled Movement of Upper Extremities

Uncontrolled upper extremity movements arise from diverse etiologies including neurodegenerative disorders (Parkinson's disease, atypical parkinsonisms), cerebrovascular disease, drug-induced syndromes, metabolic disorders, and autoimmune conditions, requiring systematic evaluation to distinguish between primary movement disorders and secondary causes.

Primary Neurodegenerative Causes

Parkinson's Disease and Parkinsonian Syndromes

• Resting tremor affecting upper extremities is the classic presentation of Parkinson's disease, appearing after approximately 40-50% of dopaminergic neurons in the substantia nigra have been lost 1
• The tremor characteristically affects various body parts and is present at rest, reduced by voluntary movement 1
• Peak onset occurs at 60-70 years, though can present in extended age ranges 1

Atypical Parkinsonian Syndromes

• Progressive Supranuclear Palsy (PSP) is the most common atypical parkinsonism with prevalence around 5/100,000, presenting classically in the sixth or seventh decade 1
• Multiple System Atrophy (MSA) typically onsets at 55-65 years, with MSA-P subtype presenting predominant extrapyramidal/parkinsonian features including tremor 1
• Early prominent gait dysfunction, rapid progression, and poor levodopa response distinguish atypical parkinsonisms from classic PD 1

Restless Legs Syndrome

• RLS is characterized by an urge to move both legs and sometimes the arms when immobile, often associated with dysesthesias in affected extremities 2
• The urge is relieved by movement and is most prominent in evening or at night 2
• Clinically significant RLS (occurring at least once weekly) is present in 2-3% of adults 2

Cerebrovascular Causes

• Post-stroke movement disorders develop after 1-4% of strokes and can manifest as a wide range of hyperkinetic disorders including chorea, ballism, athetosis, dystonia, tremor, and myoclonus 3
• Cerebrovascular diseases represent up to 22% of secondary movement disorders 3
• These can occur immediately after acute stroke or develop as delayed-onset progressive movement disorders affecting the basal ganglia or their connections 3
• Both ischemic and hemorrhagic strokes, subarachnoid hemorrhage, and cerebrovascular malformations can cause involuntary upper extremity movements 3

Drug-Induced Movement Disorders

Acute and Subacute Presentations

• Dopamine receptor blockers (neuroleptics), antidepressants, and anti-epileptics commonly induce movement disorders with acute (hours to days) or subacute (days to weeks) onset 4
• Drug-induced syndromes include acute dystonic reactions, akathisia, drug-induced parkinsonism, tremor, and various hyperkinesias 4
• A clear temporal relationship between medication initiation and symptom onset, dose-effect relationship, and resolution after discontinuation (except tardive syndromes) are characteristic features 4

Neuroleptic Malignant Syndrome and Serotonin Syndrome

• These represent life-threatening movement disorder emergencies requiring prompt identification 5
• Motor symptoms may be part of more extensive cerebral or systemic conditions 4

Tardive Dyskinesias

• Post-neuroleptic dyskinesias do not disappear when responsible neuroleptics are stopped and are usually permanent 6
• Paradoxically, treatment may require resuming neuroleptic prescription 6

Autoimmune and Inflammatory Causes

Sydenham Chorea (Acute Rheumatic Fever)

• Characterized by purposeless, involuntary, nonstereotypical movements of trunk or extremities 2
• Often associated with muscle weakness and emotional lability 2
• Can be predominantly unilateral and requires careful neurological examination 2
• Long latent period between inciting streptococcal infection and onset makes documentation of recent infection difficult 2

Metabolic and Genetic Causes

Wilson's Disease

• Can present with tremor, dystonia, and parkinsonian features affecting upper extremities 1
• Drooling and oropharyngeal dystonia are characteristic manifestations 1
• Diagnosis requires serum ceruloplasmin, 24-hour urinary copper, and slit-lamp examination for Kayser-Fleischer rings 1

Diagnostic Algorithm for Systematic Evaluation

Initial Characterization

• Characterize tremor precisely: resting versus action, frequency, body distribution, factors that worsen or improve symptoms 1
• Assess cardinal parkinsonian features: bradykinesia, rigidity, postural instability 1
• Evaluate gait pattern: shuffling, festination, freezing, wide-based ataxic gait, or lurching gait with falls 1

Red Flags for Atypical Causes

• Early prominent falls, rapid progression, poor or absent levodopa response, early autonomic dysfunction, vertical gaze palsy, and asymmetric cortical signs suggest atypical parkinsonism 1

Medication History

• Obtain thorough medication history including timing of initiation relative to symptom onset 4
• Review all dopamine receptor blockers, antidepressants, anti-epileptics, and over-the-counter medications 4

Laboratory Workup

• Serum ceruloplasmin and 24-hour urinary copper for Wilson's disease 1
• Thyroid function tests and serum ferritin 1
• Streptococcal testing if autoimmune etiology suspected 2

Imaging

• MRI brain without contrast is the optimal imaging modality to evaluate parkinsonian syndromes and cerebrovascular causes 1

Therapeutic Trial

• Levodopa/carbidopa trial: robust response supports PD diagnosis, poor response suggests atypical parkinsonism or alternative diagnosis 1

Critical Clinical Pitfalls to Avoid

• Do not overlook medication history: Many movement disorders are iatrogenic and reversible with drug discontinuation 4
• Consider multiple coexisting pathologies in elderly patients (e.g., vascular changes plus neurodegenerative disease) 1
• Exclude septic arthritis and other infectious causes when joint involvement accompanies movement disorders 2
• Recognize that over-the-counter anti-inflammatory agents may mask classic features before clinical evaluation 2
• Do not assume all tremors are benign: Life-threatening conditions like neuroleptic malignant syndrome require prompt identification and management 5