What is the initial workup for a patient presenting with shortness of breath (dyspnea)?

Initial Workup for Shortness of Breath (Dyspnea)

The initial workup for a patient presenting with shortness of breath should include chest radiography, 12-lead ECG, basic laboratory tests, and pulse oximetry to rapidly identify the underlying cause and guide appropriate treatment. 1

Step 1: Initial Assessment and Testing

History - Focus on:

• Duration of symptoms (acute vs. chronic)
• Onset (sudden vs. gradual)
• Triggers (exertion, position, environmental factors)
• Associated symptoms (chest pain, cough, fever, edema)
• Risk factors (smoking, occupational exposures, cardiac history)

Physical Examination - Key Findings:

• Vital signs (including respiratory rate and oxygen saturation)
• Respiratory system (wheezing, decreased breath sounds, crackles)
• Cardiovascular system (JVD, murmurs, extra heart sounds, edema)
• Signs of systemic disease (clubbing, cyanosis)

First-Line Diagnostic Tests:

• Chest radiography - Essential first imaging study 1
• 12-lead ECG - To assess for cardiac causes 1
• Pulse oximetry - To evaluate oxygenation status 1
• Laboratory tests:
  • Complete blood count (anemia, infection)
  • Basic metabolic panel (electrolyte disturbances, renal function)
  • Cardiac troponins (myocardial injury)
  • BNP/NT-proBNP (heart failure) 1
  • Thyroid function tests

Step 2: Directed Testing Based on Initial Findings

If Pulmonary Cause Suspected:

• Spirometry - For airflow obstruction assessment 1
• CT chest - When radiographic abnormality requires further characterization or clinical suspicion despite normal chest X-ray 1
  • Consider thin-slice CT without contrast for parenchymal disease
  • Consider CT with contrast for suspected pulmonary embolism
• Arterial blood gas - For acid-base status and gas exchange evaluation

If Cardiac Cause Suspected:

• Echocardiography - Within 48 hours if cardiac structure/function unknown 1
• BNP/NT-proBNP - To help differentiate cardiac from non-cardiac causes 1
• Cardiac stress testing - If ischemia suspected but not acute

If Multifactorial or Unclear Etiology:

• Pulmonary function tests - Complete testing including diffusion capacity
• Six-minute walk test - To objectively assess functional capacity 1
• D-dimer - If pulmonary embolism suspected

Step 3: Advanced Testing When Needed

• Right heart catheterization - For suspected pulmonary hypertension 1
• Bronchoscopy - For suspected interstitial lung disease requiring biopsy
• Cardiopulmonary exercise testing - To differentiate cardiac from pulmonary causes 1

Common Pitfalls to Avoid

1. Missing cardiac causes in patients with normal chest X-ray - Heart failure may present with minimal radiographic findings
2. Attributing dyspnea to a single cause - Up to one-third of cases have multifactorial etiology 1
3. Overlooking non-cardiopulmonary causes - Consider anemia, metabolic acidosis, neuromuscular disorders
4. Neglecting rare but serious conditions - Pulmonary hypertension, interstitial lung disease, and cardiac amyloidosis can present with progressive dyspnea 1
5. Failure to recognize "mimics" - Conditions like GERD, anxiety, or deconditioning can present as dyspnea 1

Special Considerations

• In patients with known or suspected malignancy, consider pleural effusion or malignant pleural mesothelioma, especially with history of asbestos exposure 1
• For patients with acute dyspnea and suspected heart failure, obtain BNP/NT-proBNP levels immediately 1
• Consider exercise-induced bronchoconstriction in patients with exertional dyspnea that resolves with rest 1

By following this systematic approach, clinicians can efficiently identify the cause of dyspnea and initiate appropriate treatment to improve patient outcomes and quality of life.