Approach to Chest Pain

Epidemiology

Causes of Chest Discomfort (Table 15-1, Harrison's 22E)

1. Myocardial Ischemia/Injury (Angina Pectoris)

• Results from imbalance between myocardial O2 supply and demand
• Precipitated by increased heart rate, wall stress, or contractility (demand side), or reduced coronary blood flow/O2 content (supply side)
• Stable angina: triggered by exertion, relieved by rest
• Unstable ischemia: classified by ECG (ST elevation vs. no ST elevation) and myocardial injury markers (NSTEMI, STEMI, unstable angina)
• Ischemic chest pain is typically described as pressure, heaviness, or squeezing - "like an elephant sitting on my chest"
• Radiation to the left arm, jaw, or both shoulders is characteristic
• Associated symptoms: diaphoresis, dyspnea, nausea

2. Aortic Dissection / Acute Aortic Syndrome

• Classically: sudden-onset, severe, tearing or ripping pain radiating to the back or between the scapulae
• More abrupt onset than ischemic pain
• Risk factors: hypertension, Marfan syndrome, bicuspid aortic valve

3. Pulmonary Embolism

• Pleuritic chest pain (worse with inspiration) + dyspnea + hypoxia
• May be accompanied by hemoptysis
• Risk factors: immobility, prior DVT, malignancy, pregnancy, OCP use

4. Pericarditis

• Sharp, pleuritic pain that is worse lying flat and relieved by sitting forward (leaning forward)
• May have a pericardial friction rub on auscultation
• Diffuse ST elevation (saddle-shaped) on ECG

5. Tension Pneumothorax

• Sudden onset pleuritic pain with ipsilateral decreased breath sounds, tracheal deviation, hypotension
• Medical emergency - requires immediate needle decompression

6. Esophageal/GI Causes

• Esophageal reflux (GERD): burning retrosternal pain, worse after meals, lying down; relieved by antacids
• Esophageal spasm: can mimic angina perfectly - diffuse pressure or squeezing, may radiate to jaw, arm
• Peptic ulcer disease and gallbladder disease: epigastric predominance
• Esophageal rupture (Boerhaave syndrome): among non-cardiopulmonary causes, holds the greatest diagnostic urgency

7. Musculoskeletal Causes

• Costochondritis: reproducible tenderness on palpation of the costochondral junctions
• Rib fractures, arthritis of shoulder or spine, cervical disk disease
• Chest wall pain is worsened by specific movements or direct pressure

8. Pleuropulmonary Causes

• Pneumonia with pleuritis: pleuritic pain + cough, fever, consolidation
• Pulmonary hypertension: exertional chest discomfort with dyspnea

9. Herpes Zoster

• Dermatomal, burning pain that may precede the rash by days; important not to miss

10. Psychiatric/Functional

• Panic disorder, anxiety states: diffuse, atypical features; associated with palpitations, shortness of breath, paresthesias

Structured Clinical Framework (Table 15-2, Harrison's 22E)

1. Could the chest discomfort be due to an acute, potentially life-threatening condition warranting urgent evaluation and management?

• Unstable ischemic heart disease, Aortic dissection, Pneumothorax, Pulmonary embolism

2. If not, could it be due to a chronic condition likely to cause serious complications?

• Stable angina, Aortic stenosis, Pulmonary hypertension

3. If not, could it be due to an acute condition warranting specific treatment?

• Pericarditis, Pneumonia/pleuritis, Herpes zoster

4. If not, could it be due to another treatable chronic condition?

• GERD, esophageal spasm, peptic ulcer, gallbladder disease, costochondritis, musculoskeletal disorders, anxiety

Approach to the Patient

History

Physical Examination

Diagnostic Testing

• First-line, mandatory in all patients with chest discomfort
• ST-elevation: STEMI (or pericarditis - diffuse saddle-shaped)
• ST depression / T-wave inversions: NSTEMI/unstable angina
• Sinus tachycardia + S1Q3T3 pattern (classic but insensitive): PE
• Normal ECG does not exclude ACS

• High-sensitivity troponin I or T (hs-TnI/hs-TnT): preferred; elevated in myocardial injury (MI, myocarditis, severe PE)
• Serial troponins at 0 and 1-3 hours (0/1h or 0/2h rapid rule-out protocols)
• BNP/NT-proBNP: heart failure context

• Widened mediastinum: aortic dissection
• Pleural effusion, consolidation: pneumonia/pleuritis
• Absent lung markings: pneumothorax
• Cardiomegaly, pulmonary edema: decompensated heart failure
• Hampton's hump, Westermark sign (insensitive): PE

Outpatient Evaluation of Chest Discomfort (Harrison's 22E)

• Detailed history and risk factor assessment
• Resting ECG
• Exercise stress test (or imaging stress test if baseline ECG is abnormal or patient cannot exercise)
• Coronary CT angiography (CCTA) is increasingly used as a non-invasive option in intermediate-risk patients
• Laboratory workup: lipids, fasting glucose, thyroid function (as appropriate)

Key Points to Remember

• Rule out life-threatening causes first: ACS, aortic dissection, PE, tension pneumothorax, esophageal rupture
• Atypical presentations are common: especially in women, elderly, and diabetics
• A normal ECG and initial troponin do not exclude ACS - serial testing is required
• Esophageal spasm can mimic angina pectoris perfectly, including radiation and response to nitroglycerin
• Musculoskeletal causes are common but should be a diagnosis of exclusion after cardiac causes are ruled out
• The HEART score (History, ECG, Age, Risk factors, Troponin) and TIMI/GRACE risk scores are validated tools for risk stratification in ACS