What are the causes of tremors during an acute exacerbation of chronic obstructive pulmonary disease (COPD)?

Tremors in Acute COPD Exacerbations: Causes

Tremors during acute COPD exacerbations are primarily caused by the medications used to treat the exacerbation—specifically short-acting β2-agonists (bronchodilators) and systemic corticosteroids—rather than by the exacerbation itself.

Medication-Induced Tremor

β2-Agonist Bronchodilators

The most common culprit is short-acting inhaled β2-agonists (such as albuterol/salbutamol), which are the first-line bronchodilators recommended for acute exacerbations 1. These medications cause tremor through:

• Beta-2 receptor stimulation in skeletal muscle, leading to fine tremor (typically affecting the hands)
• Dose-dependent effect: Higher doses and more frequent administration during exacerbations increase tremor severity
• The tremor is a predictable pharmacologic side effect, not a sign of toxicity at therapeutic doses

Systemic Corticosteroids

Oral or intravenous corticosteroids are routinely prescribed for acute exacerbations to improve lung function and shorten recovery time 1, 2. These contribute to tremor through:

• Metabolic effects including hypokalemia and hyperglycemia
• Direct neuromuscular effects
• Potentiation of β2-agonist effects

Methylxanthines (Theophylline/Aminophylline)

While the GOLD guidelines explicitly state that methylxanthines are not recommended owing to side effects 1, if they are used, tremor is a prominent adverse effect due to:

• Phosphodiesterase inhibition
• Increased catecholamine release
• Narrow therapeutic window with tremor often indicating near-toxic levels

Metabolic and Physiological Causes

Hypoxia and Hypercapnia

Severe exacerbations with acute respiratory failure can cause tremor through:

• Cerebral hypoxia affecting motor control centers
• CO2 retention causing asterixis (flapping tremor) in severe cases
• These represent life-threatening complications requiring immediate intervention 1

Electrolyte Disturbances

• Hypokalemia from β2-agonists and corticosteroids
• Hypomagnesemia from respiratory alkalosis or medications
• Hypoglycemia (less common, but possible with severe illness)

Clinical Approach

When evaluating tremor in acute COPD exacerbation:

1. Review medication timing: Did tremor start or worsen after bronchodilator or steroid administration?
2. Assess tremor characteristics: Fine, rapid tremor = β2-agonist; coarse, flapping = severe hypercapnia
3. Check vital signs and oxygen saturation: Rule out severe respiratory failure
4. Obtain basic metabolic panel: Check potassium, magnesium, glucose
5. Consider dose reduction of bronchodilators if tremor is intolerable but respiratory status allows

Important Caveats

• Do not discontinue bronchodilators due to tremor alone—respiratory benefit outweighs this side effect in acute exacerbations
• Tremor from medications is expected and self-limited, resolving as exacerbation treatment is tapered
• Asterixis or altered mental status with tremor indicates severe respiratory failure requiring urgent escalation of care, potentially including non-invasive ventilation 1
• If tremor is severe and persistent, consider switching to anticholinergic bronchodilators (ipratropium) which do not cause tremor, though β2-agonists remain first-line 1

The tremor itself does not require specific treatment—it is managed by addressing the underlying exacerbation and will resolve as medications are tapered during recovery.