What causes mild shaking in a hand?

Causes of Mild Hand Shaking

Mild hand shaking (tremor) is most commonly caused by essential tremor, physiologic tremor (enhanced by stress, caffeine, or fatigue), or early Parkinson's disease, though numerous other conditions including metabolic disorders, medications, and neurological diseases must be considered in the differential diagnosis.

Primary Tremor Disorders

Essential Tremor

• Essential tremor is the most common pathological cause of hand shaking, affecting 5-10 million people in the United States 1, 2
• Characterized by action and postural tremor with frequency between 4-8 Hz, primarily affecting the upper extremities 2, 3
• The tremor is maximal when hands are outstretched and may persist during movement 4
• This is a progressive neurologic disorder that can cause substantial disability in some patients 2

Physiologic Tremor

• Present in all individuals but typically not visible; can be enhanced by anxiety, stress, fatigue, or metabolic factors 3
• Only 2% of normal controls report that coffee makes their hands shaky, and caffeine (325 mg) does not significantly increase physiologic tremor in formal testing 5

Parkinsonian Tremor

• Characterized by resting tremor at 4-6 Hz that disappears with movement 4, 3
• Present when hands are at rest and involves a "pill-rolling" quality 4
• May be accompanied by other neurological signs including bradykinesia, rigidity, and gait disturbances 6

Secondary Causes to Consider

Metabolic and Systemic Disorders

• Hepatic encephalopathy causes flapping tremor (asterixis), which results from incongruity in muscle tension during wrist hyperextension with fingers spread apart 6
• Hypoglycemia can present with tremor and requires differentiation from other causes 6
• Thyroid disorders (hyperthyroidism) commonly cause fine action tremor
• Hyponatremia may present with tremor-like symptoms 6

Medication and Substance-Related

• Drug-induced tremor is common with tricyclic antidepressants, phenothiazines, antihistamines, levodopa, and MAO-inhibitors 6
• Alcohol withdrawal causes harsh and repetitive tremor, accompanied by increased heart rate and cold sweats 6
• Chronic alcohol use can lead to cerebellar tremor 6

Neurological Conditions

• Autonomic failure from diabetes, kidney or liver failure can present with tremor 6
• Cerebellar disease causes intention tremor that occurs with movement 4, 3
• Wilson's disease, peripheral neuropathy, and midbrain lesions can manifest with tremor 3
• Wernicke's encephalopathy (thiamine deficiency) presents with eye movement abnormalities, gait disturbances, and memory lapses in addition to tremor 6

Diagnostic Approach

Key Historical Features

• Determine when tremor occurs: at rest (Parkinson's), with posture/action (essential tremor), or with movement (intention tremor) 4, 3
• Assess for associated symptoms: cognitive changes, gait disturbances, autonomic symptoms 6
• Review medication history including antidepressants, antihypertensives, and antihistamines 6
• Evaluate for substance use including alcohol and caffeine 6, 5
• Screen for systemic diseases: diabetes, liver disease, kidney disease, thyroid disorders 6

Physical Examination Priorities

• Observe tremor characteristics: frequency, amplitude, and relationship to position/movement 3
• Look for flapping tremor by having patient extend wrists with fingers spread—this indicates hepatic encephalopathy if present 6
• Assess for Parkinsonian features: bradykinesia, rigidity, masked facies 6
• Evaluate for cerebellar signs: ataxia, dysmetria, nystagmus 6
• Check for autonomic dysfunction: orthostatic hypotension, impaired sweating 6

Red Flags Requiring Urgent Evaluation

• Tremor associated with altered mental status or confusion (consider hepatic encephalopathy, metabolic derangement) 6
• Acute onset with fever, headache, or neck stiffness (consider encephalitis) 6
• Tremor with hemiplegia or focal neurological deficits (consider stroke or subdural hematoma) 6
• Tremor with severe orthostatic symptoms or syncope (consider cardiac or autonomic causes) 6

Common Pitfalls

• Do not assume all tremor is benign essential tremor—always screen for secondary causes including medications, metabolic disorders, and Parkinson's disease 2, 3
• Distinguish between different tremor types based on when they occur, as this fundamentally changes diagnosis and treatment 4
• In patients with liver disease, flapping tremor indicates overt hepatic encephalopathy requiring immediate treatment 6
• Caffeine rarely causes or worsens tremor despite common belief 5
• Hyponatremia symptoms closely mimic hepatic encephalopathy and require careful differentiation 6