What are the emergent differential diagnoses for chest pain and the initial assessment and treatment steps?

Emergent Differential Diagnoses for Chest Pain

Obtain a 12-lead ECG within 10 minutes and draw high-sensitivity cardiac troponin immediately to identify or exclude the six life-threatening causes: acute coronary syndrome, aortic dissection, pulmonary embolism, tension pneumothorax, cardiac tamponade, and esophageal rupture. 1

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Life-Threatening Causes Requiring Immediate Exclusion

Acute Coronary Syndrome (ACS)

• Presentation: Retrosternal pressure, squeezing, or heaviness that builds gradually over minutes (not instantaneously), often radiating to the left arm, jaw, neck, or between the shoulder blades. 1, 2
• Associated symptoms: Diaphoresis, dyspnea, nausea, vomiting, lightheadedness, presyncope, or syncope markedly increase the likelihood of ACS. 1, 2
• Critical pitfall: 30–40% of acute myocardial infarctions present with a normal or nondiagnostic initial ECG; approximately 13% of patients with sharp, pleuritic chest pain still have acute myocardial ischemia. 1, 2
• Physical examination may be completely normal in uncomplicated myocardial infarction. 1, 2

Acute Aortic Dissection

• Presentation: Sudden-onset "ripping" or "tearing" chest or back pain that is maximal at onset, radiating to the upper or lower back. 1, 2
• Physical clues: Pulse differential between extremities (~30% of cases), systolic blood-pressure difference >20 mmHg between arms, new aortic regurgitation murmur (present in 40–75% of type A dissections). 1, 2
• High-probability triad: Severe abrupt pain + pulse differential + widened mediastinum on chest X-ray predicts >80% probability of dissection. 1, 2

Pulmonary Embolism (PE)

• Presentation: Sudden dyspnea with pleuritic chest pain that worsens on inspiration. 1, 2
• Physical findings: Tachycardia (present in >90% of patients), tachypnea (~70% of cases). 1, 2
• Risk factors: Recent surgery, immobilization, malignancy, oral contraceptive use, pregnancy. 1

Tension Pneumothorax

• Presentation: Dyspnea and sharp chest pain that intensifies with inspiration. 1, 2
• Physical findings: Unilateral absent or markedly reduced breath sounds, hyperresonant percussion, tracheal deviation, hemodynamic instability (hypotension, tachycardia). 1, 2

Cardiac Tamponade

• Presentation: Pleuritic chest pain that worsens when lying supine. 1, 2
• Physical findings: Beck's triad (jugular venous distension, hypotension, muffled heart sounds), pulsus paradoxus >10 mmHg. 1, 2

Esophageal Rupture (Boerhaave Syndrome)

• Presentation: Severe chest pain following forceful vomiting. 1, 2
• Physical findings: Subcutaneous emphysema of the neck or chest, concurrent pneumothorax (~20% of cases). 1, 2

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Immediate Assessment & Diagnostic Actions (First 10 Minutes)

Mandatory Initial Tests

• 12-lead ECG within 10 minutes to detect STEMI (≥1 mm ST-elevation in contiguous leads), ST-depression, T-wave inversions, or pericarditis patterns (diffuse ST-elevation with PR-depression). 1, 2
• High-sensitivity cardiac troponin immediately; it is the most sensitive and specific biomarker for myocardial injury. 1, 2
• Repeat high-sensitivity troponin at 1–3 hours (or conventional troponin at 3–6 hours) because a single normal result does not exclude ACS. 1

Vital Signs & Physical Examination

• Measure vital signs in both arms: Systolic blood-pressure difference >20 mmHg suggests aortic dissection; tachycardia >100 bpm occurs in >90% of PE. 1, 2
• Focused cardiovascular examination: Assess for diaphoresis, tachypnea, pulmonary crackles, S3 gallop, new murmurs (mitral or aortic regurgitation), pericardial friction rub, unilateral absent breath sounds, pulse differentials, jugular venous distension, subcutaneous emphysema. 1, 2

Serial Monitoring When Initial Tests Are Nondiagnostic

• Obtain serial ECGs every 15–30 minutes if clinical suspicion remains high to capture evolving ischemic changes. 1
• Add posterior leads V7–V9 when suspicion for ACS is intermediate-to-high and the standard ECG is nondiagnostic. 1

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Management Algorithms Based on Initial Findings

STEMI (ST-Elevation ≥1 mm in Contiguous Leads)

• Activate STEMI protocol immediately: Target door-to-balloon time <90 minutes for primary PCI (preferred) or door-to-needle time <30 minutes for fibrinolysis. 1, 3
• Pre-hospital management: Administer chewed aspirin 162–325 mg, sublingual nitroglycerin (unless systolic BP <90 mmHg or HR <50 or >100 bpm), IV morphine 4–8 mg (repeat 2 mg every 5 minutes as needed), supplemental oxygen 2–4 L/min only if dyspneic or hypoxic. 1

NSTE-ACS (ST-Depression, T-Wave Inversions, or Elevated Troponin Without ST-Elevation)

• Admit to coronary care unit: Initiate continuous cardiac monitoring, dual antiplatelet therapy (aspirin + P2Y12 inhibitor), anticoagulation (unfractionated heparin, enoxaparin, or fondaparinux), and plan urgent coronary angiography. 1, 3

Suspected Aortic Dissection

• Withhold aspirin, heparin, and all antithrombotic agents. 1
• Arrange immediate transfer to a center with 24/7 aortic imaging (CT angiography, MRI, or transesophageal echocardiography) and cardiac-surgery capability. 1

Suspected Pulmonary Embolism

• Apply Wells criteria to estimate pre-test probability. 1
• For low-to-intermediate probability: Obtain age- and sex-adjusted D-dimer; a negative result effectively rules out PE. 1
• For high probability or positive D-dimer: Proceed directly to CT pulmonary angiography. 1

Low-Risk Patients (Normal ECG, Negative Serial Troponins, Stable Vitals)

• Observe in chest-pain unit for 10–12 hours or discharge for outpatient stress testing or coronary CT angiography within 72 hours. 1

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Special Population Considerations

Women

• Higher risk of underdiagnosis: Women more frequently present with jaw/neck pain, nausea, fatigue, dyspnea, epigastric discomfort, or back pain rather than classic chest pressure. 1, 2
• Use sex-specific troponin thresholds (>16 ng/L for women vs >34 ng/L for men); universal cutoffs miss ~30% of women with STEMI. 1

Older Adults (≥75 Years)

• Atypical presentations: Isolated dyspnea, syncope, acute delirium, or unexplained falls without classic chest pain. 1, 2

Patients with Diabetes

• More likely to present with atypical symptoms: Vague abdominal symptoms, confusion, or isolated dyspnea; higher risk for silent ischemia. 1

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Critical Pitfalls to Avoid

• Do NOT rely on nitroglycerin response to differentiate cardiac from non-cardiac chest pain; esophageal spasm and other conditions may also improve. 1, 2
• Do NOT delay EMS transport for troponin testing in office or outpatient settings when ACS is suspected; immediate transport is essential. 1, 4
• Avoid the term "atypical chest pain"; describe presentations as "cardiac," "possibly cardiac," or "non-cardiac" to prevent misinterpretation as benign. 1, 2
• A normal physical examination does NOT exclude ACS; uncomplicated myocardial infarction can present with entirely unremarkable findings. 1, 2
• Sharp, pleuritic pain does NOT exclude ACS; approximately 13% of patients with pleuritic pain have acute myocardial ischemia. 1, 2
• Do NOT assume young age excludes ACS; it can occur in adolescents without traditional risk factors. 1

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Pre-Hospital & EMS Management

• Activate EMS immediately for any suspected life-threatening chest pain; personal-vehicle transport carries a 1.5% risk of cardiac arrest en route. 1
• Pre-hospital ECG acquisition enables earlier reperfusion for STEMI and reduces mortality by approximately 17%. 1
• Administer chewed aspirin 162–325 mg to alert adults without known allergy or active gastrointestinal bleeding while awaiting EMS. 1, 3