What is the initial approach to a patient presenting with pain upon inspiration?

Differential Diagnosis for Pain with Inspiration

Pain with inspiration (pleuritic pain) should immediately trigger evaluation for life-threatening causes—pulmonary embolism, pneumothorax, pneumonia, pericarditis, and myocardial infarction—before considering benign etiologies. 1, 2

Immediate Life-Threatening Causes to Exclude

Pulmonary Embolism (Most Common Serious Cause)

• Accounts for 5-21% of emergency department presentations with pleuritic chest pain 2
• Presents with tachycardia and dyspnea in >90% of patients 1
• Pain with inspiration is a cardinal feature 1
• Use validated clinical decision rules (Wells criteria or PERC) to guide d-dimer testing, ventilation-perfusion scanning, or CT angiography 2

Pneumothorax

• Dyspnea and pain on inspiration with unilateral absence of breath sounds 1
• Requires immediate chest radiography 2

Acute Coronary Syndrome

• Critical caveat: Chest tenderness on palpation or pain with inspiration markedly reduces the probability of ACS 1
• However, must still obtain ECG and troponin to definitively exclude 1, 2
• Use HEART or TIMI risk scores incorporating first troponin for risk stratification 3

Pneumonia

• Fever, localized pleuritic chest pain, friction rub may be present 1
• Regional dullness to percussion and egophony on examination 1
• Chest radiography required; document resolution at 6 weeks in smokers and patients >50 years 2

Pericarditis

• Pleuritic chest pain that increases in supine position 1
• Friction rub on examination 1
• ECG shows diffuse ST elevation and PR depression 2

Aortic Dissection

• Sudden onset severe chest or back pain 1
• Extremity pulse differential (present in only 30% of patients) 1
• Widened mediastinum on chest radiography 1

Viral Pleuritis (Most Common Benign Cause)

• Coxsackieviruses, respiratory syncytial virus, influenza, parainfluenza, mumps, adenovirus, cytomegalovirus, and Epstein-Barr virus are likely pathogens 2
• Diagnosis of exclusion after ruling out serious causes 2
• Treat with NSAIDs for pain management 2

Musculoskeletal Causes

• Costochondritis presents with tenderness of costochondral joints on palpation 1
• Pain reproducible with chest wall palpation 1
• This finding markedly reduces probability of ACS but does not exclude other serious causes 1

Initial Diagnostic Approach Algorithm

1. Perform focused cardiovascular and pulmonary examination immediately 1

   • Vital signs (tachycardia, hypotension, fever)
   • Cardiac auscultation (friction rub, murmurs, S3)
   • Pulmonary examination (breath sounds, percussion, friction rub)
   • Extremity pulses
   • Chest wall palpation

2. Obtain ECG immediately unless noncardiac cause is evident 1

   • ST-segment changes suggest ACS or pericarditis
   • If ECG unavailable in office, refer to emergency department 1

3. Order chest radiography 2

   • Identifies pneumothorax, pneumonia, widened mediastinum

4. Apply validated clinical decision rules 2

   • For PE: Wells criteria or PERC rule to guide further testing
   • For ACS: HEART score (LR 13 for high-risk 7-10) or TIMI score (LR 6.8 for high-risk 5-7) 3

5. Obtain troponin if ACS remains in differential 3, 2

6. Consider d-dimer and CT angiography if PE suspected 2

Common Pitfalls to Avoid

• Do not assume musculoskeletal cause based solely on chest wall tenderness—this reduces ACS probability but does not exclude PE, pneumothorax, or pneumonia 1
• Do not rely on clinical judgment alone—history and physical examination cannot sufficiently distinguish between causes of acute chest pain 4
• Do not skip ECG and troponin in patients with risk factors—even when pleuritic features are present 1, 2
• Do not discharge patients >50 years or smokers with pneumonia without arranging 6-week follow-up chest radiography to document resolution 2