Medicine
Differential Diagnosis of Acute Chest Pain in the Emergency Department
Quick fact
A normal ECG and a normal troponin do NOT rule out aortic dissection or pulmonary embolism, and up to 10% of acute aortic dissections are initially missed.
Why this is interesting
You're in the ER when a patient walks in clutching their chest. Every second counts, but the cause could be anything—from heartburn to a torn aorta. How do you quickly figure out what's life-threatening?
Read the full explanation
Understanding Differential Diagnosis of Acute Chest Pain in the Emergency Department
Think of acute chest pain as a signal that something is wrong somewhere in the chest—heart, lungs, aorta, esophagus, or even the chest wall. The emergency doctor's first job is to separate the few dangerous causes from the many benign ones. The classic life-threatening ones are: heart attack (ACS), a tear in the aorta (aortic dissection), a blood clot in the lungs (PE), and a torn esophagus (Boerhaave syndrome). The first step is a quick history and physical exam. For example, pain that feels like pressure or squeezing, radiates to the left arm or jaw, and is worse with exertion suggests a heart attack. Sudden, tearing pain that shoots to the back hints at aortic dissection. Sharp, stabbing pain that worsens with a deep breath could be PE or pericarditis. This initial suspicion directs the next steps: an ECG immediately to check for heart attack patterns, and blood tests like troponin for heart damage, D-dimer for PE, or CT scans to see the aorta or lungs. To build a mental model, imagine an emergency physician sorting patients into three piles: 'red' (life-threatening, treat immediately), 'yellow' (potentially serious, monitor), and 'green' (likely benign, reassure). The differential diagnosis is the process of placing each patient into the right pile, based on evidence gathered quickly and efficiently.
A deeper explanation
The underlying principle is that chest pain is a symptom, not a disease, and many different organs can refer pain to the chest because of shared nerve pathways. The goal is to identify the specific cause because treatments differ drastically: giving aspirin for a heart attack is good, but it's useless or harmful for aortic dissection (it could worsen bleeding). So the decision-making relies on diagnostic tests that exploit the mechanism of each disease. For ACS, the ECG shows ST-segment elevation or depression, and troponin leaks from dying heart muscle. For PE, a D-dimer test can rule out a clot if negative, or a CT angiogram can show it if positive. For aortic dissection, a widened mediastinum on X-ray or a CT with contrast reveals the tear. The importance lies in time: for ST-elevation MI (STEMI), door-to-balloon time (getting the patient to catheterization) should be under 90 minutes, so the differential must be done rapidly. Recent advances include high-sensitivity troponin (detect tiny amounts) and decision rules like the HEART score to predict major adverse cardiac events. Understanding the differential diagnosis also involves recognizing atypical presentations—women and diabetics may have heart attacks without classic crushing pain—and remembering that multiple causes can coexist (e.g., a PE can cause chest pain and ECG changes similar to a heart attack).