What is the appropriate evaluation and management for left-sided chest pain radiating to the left scapular region?

Evaluation and Management of Left-Sided Chest Pain with Left Subscapular Radiation

Obtain an immediate 12-lead ECG and focused history to exclude acute coronary syndrome, aortic dissection, and pulmonary embolism before considering benign musculoskeletal causes. 1

Immediate Life-Threatening Causes to Rule Out First

Acute Coronary Syndrome (ACS)

• Retrosternal pressure or discomfort that builds gradually over several minutes, radiates to the left arm, neck, or jaw, and is associated with diaphoresis, dyspnea, nausea, or lightheadedness strongly suggests ACS. 1
• Pain occurring at rest or with minimal exertion indicates possible ACS rather than stable angina. 1
• Women, elderly patients, and diabetics frequently present with atypical symptoms including sharp or left-sided pain that is actually cardiac in origin—never dismiss based on "atypical" features alone. 1, 2
• Obtain ECG within 10 minutes of presentation and measure cardiac troponin immediately, even if musculoskeletal cause seems likely. 1, 2
• If initial ECG is nondiagnostic but clinical suspicion remains high, perform serial ECGs and consider supplemental leads V7-V9 to rule out posterior myocardial infarction. 1

Aortic Dissection

• Sudden-onset "ripping" or "tearing" chest pain (described as "worst chest pain of my life") with radiation to the upper or lower back, especially in hypertensive patients or those with known bicuspid aortic valve or aortic dilation, is highly suspicious for aortic dissection. 1
• Check for pulse differentials between extremities (present in 30% of cases). 1
• Severe pain with abrupt onset plus pulse differential plus widened mediastinum on chest X-ray yields >80% probability of dissection. 1

Pulmonary Embolism

• Tachycardia plus dyspnea occurs in >90% of patients with PE, often with pleuritic chest pain that worsens with inspiration. 1, 3
• Apply validated clinical decision rules and consider D-dimer assay if PE is suspected. 4, 3

Mandatory Initial Testing

• Obtain 12-lead ECG immediately for any patient with left chest pain to detect ST-segment changes, Q waves, T-wave inversions, or signs of right heart strain. 1, 2
• Measure cardiac troponin as soon as possible if any suspicion of ACS exists. 2, 4
• Obtain chest radiograph to evaluate for other potential cardiac, pulmonary, and thoracic causes including pneumothorax, pneumonia, and mediastinal widening. 1
• Do NOT use nitroglycerin response as a diagnostic test—esophageal spasm and other non-cardiac conditions also respond to nitroglycerin, making this an unreliable discriminator. 1, 2

Features Suggesting Musculoskeletal Etiology

Once life-threatening causes are excluded, consider musculoskeletal chest pain if the following features are present:

Pain Characteristics Favoring MSK Origin

• Sharp, stabbing pain that can be localized to a very limited area, unlike the diffuse pressure of angina. 1, 2
• Pain that increases with inspiration, specific movements of the chest wall, or upper extremity motion. 2, 3
• Positional pain that worsens with specific postures or physical activities. 1, 2
• Fleeting chest pain lasting only seconds (unlikely to be ischemic heart disease). 1
• Tenderness of costochondral joints on palpation (costochondritis accounts for 42% of nontraumatic musculoskeletal chest wall pain). 2, 5

Common MSK Sources

• Costochondritis commonly affects the left side (69.2% of MSK chest wall pain is left-sided). 2
• Thoracic spine pathology including arthritis of sternoclavicular and manubriosternal joints. 2
• Chest wall muscle injuries or fibromyalgia. 5

Diagnostic Algorithm

1. Obtain ECG within 10 minutes and measure troponin immediately. 1, 2
2. Perform focused history emphasizing:
   • Nature, onset, duration, location, and radiation of pain 1
   • Precipitating and relieving factors 1
   • Associated symptoms (diaphoresis, dyspnea, nausea, syncope, palpitations) 1
   • Cardiovascular risk factors 1
3. Physical examination should assess for:
   • Diaphoresis, tachypnea, tachycardia, hypotension, crackles, S3 gallop (suggests ACS) 1
   • Pulse differentials between extremities (suggests aortic dissection) 1
   • Unilateral decreased or absent breath sounds (suggests pneumothorax) 1
   • Tenderness of costochondral joints (suggests costochondritis) 1
4. Obtain chest radiograph to evaluate for pneumothorax, pneumonia, mediastinal widening, or other thoracic pathology. 1
5. If ECG shows ischemic changes, treat according to STEMI or non-STEMI ACS guidelines immediately. 1

Risk Stratification Tools

• Use HEART score (History, ECG, Age, Risk factors, Troponin) or TIMI score to stratify risk. 6
• High-risk HEART score (7-10) has likelihood ratio of 13 for ACS. 6
• Low-risk HEART score (0-3) has likelihood ratio of 0.20, effectively ruling out ACS. 6

Management Based on Diagnosis

If ACS Confirmed or Highly Suspected

• Transfer immediately to emergency department or activate cardiac catheterization lab. 1
• Initiate aspirin, nitroglycerin, and oxygen as appropriate. 7

If Musculoskeletal Diagnosis Confirmed

• Most MSK chest wall pain is diagnosed by physical examination alone without need for diagnostic imaging. 2, 5
• Conservative management with NSAIDs is appropriate for costochondritis. 7, 5
• Provide reassurance and return precautions. 7

Critical Pitfalls to Avoid

• Never dismiss left-sided chest pain in women, elderly, or diabetic patients based on "atypical" presentation—they frequently present with sharp or left-sided pain that is actually cardiac. 1, 2
• Do not rely on pain reproducibility with palpation alone to exclude cardiac causes—obtain ECG and troponin regardless. 4
• Do not use nitroglycerin response as a diagnostic criterion. 1, 2
• Do not delay transfer to emergency department if any suspicion of ACS, aortic dissection, or PE exists. 7, 8