What is the differential diagnosis and management for a patient presenting with substernal chest pain?

Differential Diagnosis for Substernal Chest Pain

The differential diagnosis for substernal chest pain must prioritize immediate identification of life-threatening conditions—acute coronary syndrome, aortic dissection, pulmonary embolism, tension pneumothorax, and esophageal rupture—before considering more benign etiologies. 1, 2

Life-Threatening Causes Requiring Immediate Action

Acute Coronary Syndrome (ACS)

• Retrosternal pressure, heaviness, or squeezing that builds gradually over several minutes (not seconds), often radiating to the left arm, neck, or jaw 1, 2
• May occur at rest or with minimal exertion, particularly concerning for ACS 1, 2
• Associated symptoms include dyspnea, diaphoresis, nausea, lightheadedness, or syncope 1, 2
• Critical pitfall: Women, elderly patients, and those with diabetes frequently present with atypical symptoms and should never be dismissed 2
• Prior abnormal stress test (specificity 96%) and pain radiating to both arms (specificity 96%) are highly suggestive 3

Aortic Dissection

• Sudden-onset "ripping" or "tearing" chest pain radiating to the upper or lower back 1, 2
• Pulse differentials between extremities (present in 30% of cases), blood pressure differentials, or new aortic regurgitation murmur 2, 4
• Particularly suspect in hypertensive patients or those with known bicuspid aortic valve or aortic dilation 1

Pulmonary Embolism

• Acute dyspnea with pleuritic chest pain 2, 4
• Tachycardia present in >90% of patients, along with tachypnea 2, 4
• Must be excluded before considering benign etiologies in patients with pleuritic pain 4

Tension Pneumothorax

• Classic triad: dyspnea, pleuritic pain on inspiration, and unilateral absence of breath sounds with hyperresonant percussion 2, 4
• Severe dyspnea with hemodynamic compromise 1

Esophageal Rupture

• Severe substernal pain, often following forceful vomiting 1, 2

Serious But Non-Immediately Fatal Cardiac Causes

Pericarditis

• Sharp, pleuritic chest pain that worsens when supine and improves when leaning forward 2, 4
• Friction rub on examination (biphasic sound indicating pleural inflammation) 2, 4
• Widespread ST-elevation with PR depression on ECG 4
• Associated fever 2

Myocarditis

• Chest pain with fever, signs of heart failure, and S3 gallop 2, 4

Valvular Disease

• Aortic stenosis, aortic regurgitation, and hypertrophic cardiomyopathy can all cause substernal chest pain 2

Common Benign Causes

Costochondritis/Chest Wall Pain

• Tenderness of costochondral joints on palpation, pain reproducible with chest wall pressure 2
• Critical pitfall: 7% of patients with reproducible chest wall tenderness still have ACS—never assume this excludes serious pathology 4
• Pain localized to a very limited area, affected by palpation, breathing, turning, twisting, or bending 2

Gastroesophageal Reflux Disease/Esophagitis

• Burning retrosternal pain related to meals, relieved by antacids 2
• Critical pitfall: Nitroglycerin response should NOT be used as a diagnostic criterion, as esophageal spasm and other conditions also respond to nitroglycerin 1, 2, 4

Critical Historical Features to Distinguish Causes

Features SUGGESTING Cardiac Ischemia:

• Gradual onset over minutes (not seconds or hours) 1, 2
• Retrosternal pressure/heaviness/squeezing quality 1, 2
• Radiation to left arm, neck, or jaw 1, 2
• Precipitation by exertion or emotional stress 1, 2
• Associated dyspnea, diaphoresis, nausea, or syncope 1, 2

Features SUGGESTING Non-Ischemic Etiology:

• Sharp pain increasing with inspiration and lying supine 1, 2
• Fleeting pain lasting only seconds 1, 2
• Pain localized to a very small area or radiating below the umbilicus 1, 2
• Positional chest pain 1

Immediate Diagnostic Algorithm

Step 1: ECG Within 10 Minutes

• Obtain and review ECG within 10 minutes of arrival to identify STEMI, regardless of setting 1, 4
• Look for ST-segment elevation, new left bundle branch block, Q waves, new T-wave inversions, or ST-segment depression (specificity 95%, LR 5.3) 1, 3
• Any evidence of ischemia on ECG has specificity of 91% and LR of 3.6 3

Step 2: Cardiac Troponin Measurement

• Measure cardiac troponin as soon as possible after presentation in all patients with acute chest pain and suspected ACS 1, 4
• Critical pitfall: In office settings, do NOT delay transfer to the ED for troponin testing—transport urgently by EMS 1, 4

Step 3: Risk Stratification

• HEART score (0-10): High-risk range (7-10) has LR of 13 for ACS; low-risk range (0-3) has LR of 0.20 for excluding ACS 3
• TIMI score (0-7): High-risk range (5-7) has LR of 6.8 for ACS; low-risk range (0-1) has LR of 0.31 for excluding ACS 3

High-Risk Features Requiring Immediate Action

• Age >75 years with accompanying dyspnea, syncope, acute delirium, or unexplained fall 2
• Women presenting with atypical symptoms 2
• Patients with diabetes, renal insufficiency, or dementia 2
• Any clinical evidence of ACS or life-threatening causes in office setting should be transported urgently to ED by EMS 1

Physical Examination Priorities

• Focused cardiovascular examination to identify complications and aid diagnosis 1
• Vital signs: tachycardia and tachypnea present in >90% of PE cases 4
• Pulse and blood pressure differentials between extremities (aortic dissection) 2
• Unilateral decreased breath sounds (pneumothorax or large pleural effusion) 4
• Cardiac auscultation for friction rub (pericarditis), new murmurs (valvular disease, aortic dissection), or S3 gallop (myocarditis, heart failure) 2, 4
• Chest wall palpation for reproducible tenderness, but never use this alone to exclude ACS 4