What are the clinical findings and management strategies for postural tremor?

Clinical Findings of Postural Tremor

Postural tremor is most reliably assessed by observing the patient with arms extended in the "wing posture" position (arms flexed at elbows, hands at shoulder level), which reveals more severe tremor than the traditional outstretched arm position in essential tremor cases.

Key Clinical Characteristics by Tremor Type

Essential Tremor (Most Common)

• Bilateral postural and kinetic tremor affecting primarily the hands, with frequency of 4-12 Hz 1, 2
• Wing posture position elicits more severe tremor than outstretched arms in 37.5% of cases, making it the superior examination technique 1
• Tremor may involve head, voice, and legs in addition to upper extremities 2
• Alcohol improves tremor in 60-70% of patients, a distinguishing clinical feature 2
• Autosomal dominant inheritance pattern in approximately 60% of cases 2

Drug-Induced Postural Tremor

• Psychiatric medications are common culprits: lithium, valproic acid, lamotrigine, antidepressants, and neuroleptics 3
• Clinical presentation mimics essential tremor but temporal relationship to medication initiation is key 3
• Check medication list systematically in all patients presenting with new-onset postural tremor 3

Parkinsonian Postural Tremor

• Asymmetric onset distinguishes it from essential tremor 2
• Predominantly rest tremor (4-6 Hz) but postural component may be present 2
• Frequently involves legs and face, unlike essential tremor 2
• Associated with other parkinsonian features (rigidity, bradykinesia) 2

Orthostatic Tremor

• High-frequency tremor (13-18 Hz) primarily in legs when standing 2, 4
• Causes postural instability and unsteadiness relieved by sitting or walking 4
• 25% have "OT plus" syndrome with associated parkinsonism, restless legs syndrome, or dyskinesias 4
• Often underdiagnosed with average 5.7-year delay from symptom onset to diagnosis 4

Critical Examination Techniques

Optimal Positioning for Assessment

• Wing posture (arms flexed at elbows, hands at shoulder level) is superior to outstretched arms for detecting postural tremor severity 1
• Outstretched arm position underestimates tremor severity in essential tremor cases 1
• Observe tremor during sustained posture, during movement toward target (kinetic), and at rest 2

Distinguishing Features to Document

• Symmetry vs asymmetry of tremor onset and distribution 2
• Frequency: high-frequency (>12 Hz) suggests orthostatic tremor; 4-6 Hz suggests parkinsonian tremor; 4-12 Hz suggests essential tremor 2, 4
• Body parts affected: isolated hand tremor vs involvement of head, voice, legs 2
• Alcohol responsiveness: improvement with alcohol strongly suggests essential tremor 2
• Temporal relationship to medications: recent initiation of lithium, valproate, antidepressants, or neuroleptics 3

Management Strategies

First-Line Pharmacotherapy

• Propranolol (non-selective beta-blocker) for postural and action tremors 2, 3
• Primidone as alternative or adjunct to propranolol 2, 3
• Gabapentin for refractory cases, orthostatic tremor, or when beta-blockers contraindicated 2, 3
• Benzodiazepines (clonazepam) for selected cases 2, 3

Drug-Induced Tremor Management

• Discontinue or reduce offending medication when possible 3
• If medication cannot be stopped: beta-blockers, primidone, gabapentin, topiramate, or benzodiazepines 3
• Treatment response to drug-induced tremor is generally poor compared to essential tremor 3

Surgical Intervention

• Thalamic deep brain stimulation for severely disabling, medication-refractory tremor 5
• MRI-guided focused ultrasound (MRgFUS) thalamotomy achieves 56% tremor improvement at 2-4 years with sustained improvement in postural tremor (70%) and action tremor (63%) 5
• Reserved for patients with significant functional impairment despite maximum medical therapy 5

Common Pitfalls to Avoid

• Examining only with outstretched arms misses tremor severity best revealed in wing posture position 1
• Failing to obtain medication history overlooks drug-induced causes that are potentially reversible 3
• Not testing alcohol responsiveness (by history) misses a key diagnostic feature of essential tremor 2
• Assuming isolated postural tremor excludes inflammatory myopathy: obtain creatine kinase levels as routine screening, as inflammatory myopathy can present with isolated tremor 6
• Diagnosing orthostatic tremor as anxiety or functional disorder due to its rarity and high-frequency nature requiring EMG confirmation 4
• Missing "OT plus" syndrome: 25% of orthostatic tremor patients develop parkinsonism or other neurological features, often years after tremor onset 4