Three Key Differential Diagnoses for Chest Pain with Shortness of Breath
1. Acute Coronary Syndrome (ACS)
ACS must be considered first in any patient presenting with chest pain and dyspnea, regardless of pain character, as sharp or stabbing pain does not exclude cardiac ischemia. 1, 2
Clinical Features to Assess:
- Age and risk factors are critical: At 49 years old, patients enter high-risk demographics for coronary disease, particularly with hypertension, diabetes, smoking history, or family history of CAD 1, 2
- Pain characteristics: While typical angina is retrosternal pressure radiating to the left arm, jaw, or neck, ACS frequently presents atypically—especially in diabetics, women, and elderly patients—with sharp, stabbing pain or isolated dyspnea 1, 2
- Associated symptoms suggesting ACS: Diaphoresis, nausea, lightheadedness, presyncope, or upper abdominal discomfort 1, 2
- Exertional component: Symptoms triggered by physical activity or emotional stress increase likelihood of ischemia 1
Immediate Diagnostic Actions:
- Obtain 12-lead ECG within 10 minutes of presentation to identify ST-segment changes, T-wave inversions, or new Q waves 1, 2
- Measure high-sensitivity cardiac troponin immediately and serially, as initial troponin may be normal in early presentation 1, 2
- Physical examination may reveal diaphoresis, tachycardia, hypotension, crackles, S3 gallop, or new mitral regurgitation murmur, though examination is frequently normal in uncomplicated cases 1
Critical Pitfall:
Relief with nitroglycerin is not diagnostic of myocardial ischemia and should not be used as a diagnostic criterion, as esophageal disorders can also respond to nitroglycerin 1
2. Pulmonary Embolism (PE)
PE is a life-threatening cause of chest pain with dyspnea that frequently mimics ACS and pneumonia, characterized by pleuritic chest pain, tachycardia, and tachypnea in over 90% of patients. 1, 2
Clinical Features to Assess:
- Classic triad: Dyspnea (most common), pleuritic chest pain (sharp pain worsening with inspiration), and tachycardia 1, 2
- Risk factors: Recent immobilization, surgery within 4 weeks, active malignancy, prior DVT/PE, long-distance travel, oral contraceptives, pregnancy, or thrombophilia 1, 3
- Pain character: Sharp, pleuritic pain that increases with deep breathing suggests peripheral PE with pulmonary infarction; central chest pain may indicate central PE 1
- Hemoptysis may be present but is not required for diagnosis 1
Immediate Diagnostic Actions:
- Clinical probability assessment using Wells score or revised Geneva score to stratify as PE-likely or PE-unlikely 1
- D-dimer testing if PE-unlikely by clinical probability (negative D-dimer effectively excludes PE in low-risk patients) 1
- CT pulmonary angiography is the definitive diagnostic test for PE-likely patients or when D-dimer is elevated 1, 3
- ECG findings: May show sinus tachycardia, right axis deviation, S1Q3T3 pattern, T-wave inversions in V1-V4 (precordial leads), or right bundle branch block—patterns that can mimic ACS 1, 4, 5
- Echocardiography may reveal right ventricular dilation (RV/LV ratio >0.6), RV hypokinesia, McConnell sign (RV free wall hypokinesia with apical sparing), tricuspid regurgitation, or elevated pulmonary artery pressure 1
Critical Pitfall:
PE is frequently misdiagnosed as pneumonia due to overlapping symptoms of fever, pleuritic pain, and pulmonary infiltrates, particularly in elderly patients—maintain high suspicion even with infiltrates on chest X-ray 3, 6, 7
3. Acute Pericarditis
Acute pericarditis presents with sharp, pleuritic chest pain that characteristically worsens with inspiration and lying supine, and improves when sitting forward. 1, 2
Clinical Features to Assess:
- Pain characteristics: Sharp, stabbing chest pain that is positional—worse when supine, improved when sitting up and leaning forward 1, 2
- Pleuritic component: Pain increases with deep inspiration, coughing, or swallowing 1
- Radiation: May radiate to the trapezius ridge (highly specific for pericarditis) 1
- Associated symptoms: May include low-grade fever, malaise, or preceding viral illness 1
Immediate Diagnostic Actions:
- Auscultation for pericardial friction rub: A high-pitched, scratchy sound best heard at the left sternal border with the patient leaning forward (present in only 30-50% of cases) 1, 2
- 12-lead ECG: Look for diffuse ST-segment elevation (concave upward) with PR-segment depression in multiple leads, distinguishing it from the convex ST elevation and reciprocal changes of STEMI 1
- Echocardiography: Assess for pericardial effusion (though absence does not exclude pericarditis) and evaluate for cardiac tamponade if effusion is present 1
- Inflammatory markers: Elevated ESR, CRP, and white blood cell count support diagnosis 1
- Troponin: May be mildly elevated if myopericarditis is present 1
Critical Pitfall:
Do not confuse pericarditis with ACS—the diffuse ST elevation without reciprocal changes and positional nature of pain are key distinguishing features, but always obtain troponin and echocardiography to exclude concurrent myocardial involvement 1
Additional Life-Threatening Diagnoses to Exclude
Aortic Dissection:
- Sudden-onset "ripping" or "tearing" chest pain radiating to the back, particularly in hypertensive patients or those with known bicuspid aortic valve or aortic dilation 1, 2
- Check for pulse differentials between extremities and blood pressure differences >20 mmHg between arms 1, 2
Pneumothorax:
- Sudden-onset sharp, pleuritic chest pain with dyspnea, decreased breath sounds, and hyperresonance on affected side 2
- Confirm with chest X-ray showing visceral pleural line 2