What is the differential diagnosis and initial management of acute chest pain?

Differential Diagnosis of Acute Chest Pain

The differential diagnosis of acute chest pain must immediately prioritize identification of life-threatening conditions—acute coronary syndrome (ACS), acute aortic dissection, pulmonary embolism, tension pneumothorax, pericarditis with tamponade, and esophageal rupture—within the first 10 minutes through ECG acquisition and focused clinical assessment. 1, 2

Life-Threatening Causes Requiring Immediate Action

Acute Coronary Syndrome (STEMI/NSTEMI/Unstable Angina)

• Presentation: Retrosternal pressure, heaviness, or squeezing that builds gradually over minutes (not seconds), radiating to left arm, neck, jaw, or back 1, 2
• Associated symptoms: Diaphoresis, dyspnea, nausea, vomiting, or syncope—these autonomic features strongly suggest cardiac origin 1, 3
• Key features: Pain typically lasts >10 minutes, may occur at rest or with minimal exertion, and is NOT relieved by position changes 1, 2
• Critical pitfall: Women and elderly patients (≥75 years) frequently present with atypical symptoms including isolated dyspnea, nausea, fatigue, jaw pain, or epigastric discomfort without classic chest pain 1, 3, 2

Acute Aortic Dissection

• Presentation: Sudden-onset "ripping" or "tearing" chest pain with maximal intensity at onset (unlike ACS which builds gradually) 1, 2
• Radiation pattern: Pain radiates to upper or lower back between scapulae 2
• Physical findings: Pulse differentials between extremities, blood pressure differentials >20 mmHg between arms, new aortic regurgitation murmur 2, 4
• Risk factors: Advanced age, uncontrolled hypertension, known connective tissue disorders (Marfan, Ehlers-Danlos), prior aortic procedures 4

Pulmonary Embolism

• Presentation: Acute dyspnea with pleuritic chest pain (sharp, worsens with inspiration) 1, 2
• Physical findings: Tachycardia present in >90% of cases, tachypnea, hypoxemia 2
• Associated features: Hemoptysis, unilateral leg swelling, recent immobilization, surgery, or known hypercoagulable state 2, 5

Tension Pneumothorax

• Presentation: Sudden-onset severe dyspnea with sharp, unilateral chest pain 2
• Physical findings: Unilateral absence of breath sounds, tracheal deviation away from affected side, jugular venous distension, hypotension 2, 5
• Context: Often follows trauma, mechanical ventilation, or occurs spontaneously in tall, thin young males 5

Serious But Non-Immediately Fatal Causes

Pericarditis

• Presentation: Sharp, pleuritic chest pain that worsens when supine and improves when leaning forward 1, 2
• Physical findings: Pericardial friction rub (pathognomonic but present in <50% of cases), fever 2, 4
• ECG findings: Diffuse ST-segment elevation (unlike localized elevation in STEMI), PR depression 1

Myocarditis

• Presentation: Chest pain with fever, signs of heart failure (dyspnea, orthopnea, peripheral edema) 2
• Physical findings: S3 gallop, tachycardia out of proportion to fever 2, 4
• Context: Often follows recent viral illness 4

Pneumonia with Pleurisy

• Presentation: Pleuritic chest pain (sharp, worsens with breathing) with productive cough, fever 5
• Physical findings: Crackles, bronchial breath sounds, dullness to percussion 5
• Key feature: Pain is clearly related to respiratory movements 5

Common Benign Causes

Costochondritis/Tietze Syndrome

• Presentation: Sharp or aching chest wall pain, often localized to costochondral junctions 1, 2
• Physical findings: Tenderness of costochondral joints on palpation, pain reproducible with chest wall pressure 2
• Key feature: Pain affected by palpation, breathing, turning, twisting, or bending 2

Gastroesophageal Reflux Disease (GERD)/Esophageal Spasm

• Presentation: Burning retrosternal pain related to meals, worse when lying down 2
• Relief pattern: Responds to antacids (but this does NOT exclude ACS—esophageal spasm also responds to nitroglycerin) 3, 6
• Critical pitfall: Never use nitroglycerin response as a diagnostic tool for ACS 3, 2

Musculoskeletal Chest Wall Pain

• Presentation: Pain localized to very limited area, sharp quality 2
• Key features: Reproducible with specific movements, affected by position changes, no radiation to typical cardiac distribution 2

Critical Discriminating Features in History

Features STRONGLY Suggesting ACS:

• Gradual onset over minutes (not sudden or lasting seconds) 2
• Retrosternal pressure/heaviness/squeezing quality 1, 2
• Radiation to left arm, neck, jaw, or both arms 1, 2
• Precipitation by exertion or emotional stress 2
• Associated diaphoresis, nausea, or dyspnea 1, 3
• Multiple cardiac risk factors: age >55 men/>65 women, diabetes, hypertension, hyperlipidemia, smoking, family history of premature CAD 3

Features Suggesting NON-Ischemic Etiology:

• Sharp pain increasing with inspiration (pleuritic) 2
• Pain lasting only seconds (fleeting) 2
• Pain localized to very small area (size of fingertip) 2
• Pain radiating below umbilicus 2
• Pain completely relieved by position changes 2
• Pain reproducible with palpation 2

Mandatory Initial Assessment (Within 10 Minutes)

Immediate Actions:

1. 12-lead ECG within 10 minutes to identify STEMI (ST-elevation ≥1mm in contiguous leads), new left bundle branch block, ST-depression, or T-wave inversions 1, 7
2. Repeat ECG if initial nondiagnostic but clinical suspicion remains high or symptoms persist 1, 7
3. Supplemental leads V7-V9 reasonable if posterior MI suspected 1
4. Cardiac troponin measurement as soon as possible in ED setting (do NOT delay transfer from office for troponin testing) 1, 7
5. Chest radiograph to evaluate for pneumothorax, pneumonia, widened mediastinum (aortic dissection), pulmonary edema 1, 7

Physical Examination Priorities:

• Vital signs: Blood pressure in both arms (differential >20 mmHg suggests dissection), heart rate, respiratory rate, oxygen saturation 2, 4
• Cardiovascular: New murmurs (aortic regurgitation in dissection), S3 gallop (heart failure), pericardial friction rub 1, 2
• Pulmonary: Unilateral decreased breath sounds (pneumothorax, PE), crackles (heart failure, pneumonia) 2, 5
• Extremities: Pulse differentials, unilateral leg swelling (DVT/PE) 2, 4
• Chest wall: Reproducible tenderness (costochondritis) 2

Critical Pitfalls to Avoid

1. Never dismiss chest pain in women or elderly patients—they frequently present with atypical symptoms (nausea, dyspnea, fatigue, jaw pain) without classic chest pressure 1, 3, 2

2. Never use nitroglycerin response as diagnostic criterion—esophageal spasm and other non-cardiac conditions also respond to nitroglycerin 3, 2, 6

3. Never assume young age excludes ACS—it can occur even in adolescents without traditional risk factors 3

4. Never assume sharp, pleuritic pain excludes ACS—pericarditis and atypical presentations can occur 2

5. Never delay transfer to ED for troponin testing in office setting—if ACS suspected, transport urgently by EMS 1, 3, 7

6. Never rely solely on initial ECG—up to 50% of acute MI patients have non-diagnostic initial ECG; serial ECGs are essential 1

7. Never discharge patients with equivocal presentations without objective testing—2-4% of acute MI patients are inappropriately discharged from ED, more commonly women 1

Disposition Algorithm

If STEMI on ECG: Immediate activation of catheterization lab, door-to-balloon time <90 minutes (or thrombolysis if PCI unavailable within 120 minutes) 3, 7

If ST-depression or T-wave inversions: Treat as NSTE-ACS, serial troponins, risk stratification (TIMI/GRACE score), cardiology consultation 1, 3, 7

If suspected aortic dissection: Immediate CT angiography chest/abdomen/pelvis, cardiothoracic surgery consultation, blood pressure control 4

If suspected PE: D-dimer if low-risk, CT pulmonary angiography if moderate-to-high risk, anticoagulation if confirmed 2, 5

If nondiagnostic ECG with persistent symptoms or high clinical suspicion: Serial ECGs every 15-30 minutes, serial troponins at 0 and 3 hours (or 0 and 1 hour with high-sensitivity troponin), continuous cardiac monitoring 1, 7

If clearly benign etiology (reproducible chest wall tenderness, young patient with fleeting pain): Reassurance, NSAIDs for musculoskeletal pain, PPI trial for GERD, but maintain low threshold for objective testing if any atypical features 2