Textbook of Urgent Care Medicine, Chapter 21, Chest Pain

Published on October 26, 2026

Original author: Michael B. Weinstock

Originally published in 2014. Substantially updated and clinically reviewed in 2026 to reflect current evidence, guidelines, and urgent care practice.

Introduction

Chest pain represents a unique challenge in urgent care medicine; many causes are benign, prompting the urgent care provider to let down their guard. If the symptoms are deemed sufficiently concerning for an immediately life-threatening etiology, a second level of decision making occurs: How should the patient be transported?

The practical problem has not changed: acute coronary syndrome (ACS) is common, but pulmonary embolism (PE), acute aortic syndrome, tension pneumothorax, cardiac tamponade, and esophageal rupture can be equally or more immediately lethal. The urgent care task is not to name every cause at the first visit; it is to identify who cannot safely remain in the outpatient setting.

This chapter divides the differential diagnosis into life-threatening and non-life-threatening causes. Evaluate each patient from a think-worst-first mentality, then streamline the evaluation toward more common causes and management.

Presentation

Rarely do patients present as we learned in medical school. Avoid labeling potentially ischemic symptoms as atypical. Chest pain or pressure remains the most common symptom of ACS in both men and women, but ischemia may also present with dyspnea, fatigue, nausea, diaphoresis, weakness, or discomfort in the arm, shoulder, jaw, neck, back, or upper abdomen. Women may have accompanying nausea or shortness of breath more often than men. Older adults and patients with diabetes may have less prominent chest discomfort.

Differential Diagnosis

The Top Six Causes

• ACS or acute myocardial infarction
• Pulmonary embolism (PE)
• Acute aortic syndrome (including aortic dissection)
• Tension pneumothorax
• Pericarditis, myocarditis, or cardiac tamponade
• Esophageal rupture (Boerhaave syndrome)

The first three are more difficult and more common. Risk stratification based on the history, physical examination, ECG, and, when appropriate, validated testing pathways guides evaluation and disposition.

Considerations of Testing

An ECG should be acquired and reviewed for STEMI within 10 minutes of arrival in any patient with acute chest pain or an anginal-equivalent presentation. If the first ECG is nondiagnostic but suspicion remains high, serial ECGs may be necessary.

Cardiac troponin testing is not currently CLIA-waived and therefore is not generally available in urgent care centers operating under a CLIA Certificate of Waiver. Centers with the appropriate nonwaived laboratory certification may have access to troponin testing, but suspected ACS still requires interpretation through a validated serial high-sensitivity cardiac troponin (hs-cTn) pathway. A normal ECG or an isolated troponin result does not by itself exclude ACS. When ACS remains a concern, do not delay EMS/ED transfer in order to obtain outpatient biomarker testing.

Chest radiography may identify pneumothorax, pneumonia, pleural disease, or another diagnosis, but a normal radiograph does not exclude PE or acute aortic syndrome. Order testing to answer a clinical question, not simply because the patient has chest pain.

Non-Life-Threatening Causes of Chest Pain

• Pneumonia, asthma, or pleurisy
• Gastroesophageal reflux disease, peptic ulcer disease/gastritis, esophageal irritation, pancreatitis, or biliary disease
• Costochondritis or musculoskeletal chest-wall strain; cervical or thoracic radicular pain
• Herpes zoster
• Breast or chest-wall disease
• Anxiety or panic disorder after dangerous causes have been considered

Triage Pearls

• If ACS is suspected, obtain an ECG immediately and activate EMS when the patient is unstable, has ongoing concerning symptoms, or has STEMI/high-risk ischemic findings. Do not allow a patient with suspected ACS to drive themselves.
• For alert adults with nontraumatic chest pain in whom ACS is suspected and no contraindication exists, chewable aspirin 162-325 mg may be given while EMS is being activated.
• Hypotension, hypoxemia, severe respiratory distress, syncope, sustained arrhythmia, new focal neurologic deficit, unequal pulses, or an acutely ill appearance should move the visit out of the routine outpatient pathway.

History Pearls

The front-door, back-door approach remains useful. The front door gathers the history systematically. The back door specifically asks whether the story fits ACS, PE, acute aortic syndrome, tension pneumothorax, inflammatory cardiac disease/tamponade, or esophageal rupture.

Table 1. OLD CAAAR Mnemonic

History element
Onset
Location
Duration
Character
Aggravating factors
Alleviating factors
Associated symptoms
Radiation

Do not use the presence or absence of traditional coronary risk factors to rule ACS in or out during an acute visit. Ask specifically about exertional symptoms, rest relief, diaphoresis, dyspnea, prior coronary disease, stimulant use, recent immobilization or surgery, VTE history, pregnancy/postpartum status, connective-tissue or known aortic disease, and abrupt maximal-at-onset pain.

Acute Coronary Syndrome

• Chest discomfort that is exertional, pressure-like, associated with diaphoresis or dyspnea, or occurs in a patient with known coronary disease should increase concern, but no single symptom pattern is sufficiently reliable to exclude ACS.
• Reproducible chest-wall tenderness or pleuritic quality may make a noncardiac cause more likely, but neither finding alone rules out MI.
• Patients can be considered low risk only through an evidence-based clinical decision pathway appropriate to the setting. HEART Pathway-type approaches require troponin testing, typically serial hs-cTn, and therefore usually cannot be completed in a CLIA-waived urgent care center. Do not use an incomplete HEART-type pathway, a normal ECG, or clinical gestalt to call ACS “ruled out.”
• For most urgent care centers, the practical ACS pathway is history, focused examination, immediate ECG, aspirin when appropriate, and EMS/ED transfer when suspicion remains meaningful. Serial troponin-based rule-out belongs in an ED or other appropriately certified setting; it should not become a reason to keep a potentially ischemic patient in urgent care.

Pulmonary Embolism

• Pain or swelling of a lower extremity
• Recent surgery, trauma, or prolonged immobilization
• Prior DVT or PE
• Hemoptysis
• Active cancer
• Estrogen exposure or pregnancy/postpartum state

PERC is a rule-out tool only for patients who are already judged to be at low pretest probability for PE. If all PERC items are negative in an appropriately selected low-risk patient, no further PE testing is generally needed. Do not apply PERC to moderate- or high-risk patients.

Table 2. Pulmonary Embolism Rule-Out Criteria (PERC)

PERC item	Negative criterion
Age	<50 years
Pulse	<100 beats/min
Oxygen saturation	>=95% on room air
Leg examination	No unilateral leg swelling
Hemoptysis	None
Recent surgery/trauma	None requiring hospitalization within 4 weeks
Prior VTE	No prior PE or DVT
Estrogen	No exogenous estrogen use

For low- or intermediate-risk patients who are not PERC negative, D-dimer testing is appropriate when available. In patients older than 50 years, an age-adjusted D-dimer threshold can reduce unnecessary imaging. Patients with high clinical probability or a positive indicated D-dimer require ED-level imaging and management.

Acute Aortic Syndrome

• Think beyond the classic tearing description. High-risk pain is often abrupt, severe, and maximal at onset, and may involve the chest, back, or abdomen.
• High-risk conditions include known thoracic aortic aneurysm, Marfan syndrome or another heritable connective-tissue disorder, family history of aortic disease, known aortic valve disease, or recent aortic manipulation.
• High-risk examination findings include pulse or blood-pressure differential, a new aortic-regurgitation murmur, focal neurologic deficit with pain, hypotension, or shock.
• Chest x-ray is neither sensitive nor specific enough to exclude acute aortic syndrome. CT angiography is the usual definitive test in a stable patient, but that evaluation belongs in the ED/hospital pathway. A low ADD-RS combined with a negative D-dimer may be useful in selected low-probability ED patients; do not use D-dimer as a stand-alone rule-out test.

Physical Exam Pearls

• Vital signs: heart rate, respiratory rate, oxygen saturation, temperature, and blood pressure. Unexplained hypotension, tachycardia, bradycardia, or hypoxemia is worrisome.
• If acute aortic syndrome is a concern, compare pulses and obtain blood pressure in both arms when feasible without delaying transfer.
• Assess jugular venous distention.
• Compare breath sounds and assess for rales, wheeze, or signs of pneumothorax.
• Inspect the chest for rash and scars; palpate for tenderness or subcutaneous air.
• Assess rhythm, murmurs, gallop, friction rub, and distant heart sounds.
• Look for unilateral leg swelling, edema, cyanosis, or pulse deficits.

Diagnosis Pearls

The first job of the urgent care provider is to consider the life-threatening causes before settling on a benign diagnosis. The second job is to know when the available urgent-care tools are insufficient to finish that evaluation safely.

A normal ECG does not exclude ACS. A normal oxygen saturation does not exclude PE. A normal chest x-ray does not exclude acute aortic syndrome. These tests are useful only in the context of pretest probability and an appropriate pathway.

Pericarditis and myocarditis deserve particular caution when chest pain follows a viral syndrome or is accompanied by arrhythmia, heart failure symptoms, troponin elevation, or hemodynamic abnormality. ECG, biomarkers, echocardiography, and advanced imaging may be required; high-risk presentations should be evaluated in the ED/hospital setting.

Table 3. Features That Should Push Toward EMS/ED Evaluation

Concern	Examples
ACS	Ongoing/rest pain; ischemic ECG change; hemodynamic instability; known CAD with concerning new symptoms; or meaningful ACS concern in a setting that cannot perform a validated serial troponin pathway
PE	High clinical probability; hypoxemia; syncope; hypotension; DVT signs; positive indicated D-dimer without local definitive imaging
Acute aortic syndrome	Abrupt severe/maximal-at-onset pain; pulse/BP differential; neurologic deficit; new AR murmur; hypotension/shock; known aneurysm or genetic aortopathy
Other emergencies	Tension pneumothorax, tamponade, suspected esophageal rupture, severe myocarditis/pericarditis, or another unstable diagnosis

Treatment Pearls

If a life-threatening diagnosis is still in play, treatment is stabilization plus transfer – not a therapeutic trial intended to prove a benign diagnosis.

• Gastroesophageal reflux disease: an acid-suppressing medication may provide symptomatic relief after dangerous causes have been reasonably excluded, but response to treatment is not a diagnostic test.
• Musculoskeletal chest pain: NSAIDs or acetaminophen may be used when appropriate. Avoid using opioid response as a diagnostic maneuver.
• Asthma: chest tightness that is new, exertional, or disproportionate to wheezing should prompt consideration of other causes. Treat confirmed asthma according to current asthma guidance.
• Anxiety: anxiety and panic can cause chest symptoms, but anxiety also accompanies MI and PE. Do not use anxiolytic response to rule out life-threatening disease.
• Herpes zoster: antiviral therapy is most useful when started early and may still be appropriate with ongoing new lesions or in higher-risk patients. Routine systemic corticosteroids are not required to prevent postherpetic neuralgia.

Medicolegal Pearls

• Document the dangerous diagnoses considered, the key positive and negative findings, ECG interpretation, and why the chosen disposition is appropriate.
• Do not use TIMI, Wells, HEART, PERC, or another score outside the population and testing environment in which it is validated. A score is an adjunct to – not a substitute for – clinical judgment and required testing.
• Document unresolved abnormal vital signs; discharging a patient with unexplained hemodynamic or respiratory abnormality is a high-risk event.
• Chest-wall tenderness and pleuritic pain cannot be used by themselves to rule out MI or PE.
• Keep anginal equivalents in mind: ischemia may present with dyspnea, fatigue, or discomfort in the back, upper abdomen, jaw, shoulder, or arm.
• Patients with STEMI or another suspected immediately life-threatening cause should be transported by EMS rather than driving themselves.

References

1. Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline for the evaluation and diagnosis of chest pain. Circulation. 2021;144:e368-e454.
2. Kontos MC, de Lemos JA, Deitelzweig SB, et al. 2022 ACC Expert Consensus Decision Pathway on the evaluation and disposition of acute chest pain in the emergency department. J Am Coll Cardiol. 2022;80:1925-1960.
3. Rao SV, O’Donoghue ML, Ruel M, et al. 2025 ACC/AHA/ACEP/NAEMSP/SCAI guideline for the management of patients with acute coronary syndromes. Circulation. 2025.
4. U.S. Food and Drug Administration. CLIA – Clinical Laboratory Improvement Amendments – Currently Waived Analytes. FDA database. Updated October 19, 2026.
5. Centers for Medicare & Medicaid Services. CLIA Certification Quick Start Guide. March 2026.
6. American College of Emergency Physicians Clinical Policies Subcommittee (Writing Committee) on Thromboembolic Disease. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected acute venous thromboembolic disease. Ann Emerg Med. Updated policy.
7. Isselbacher EM, Preventza O, Hamilton Black J III, et al. 2022 ACC/AHA guideline for the diagnosis and management of aortic disease. Circulation. 2022;146:e334-e482.
8. Schulz-Menger J, Collini V, Groeschel JW, et al. 2025 ESC Guidelines for the management of myocarditis and pericarditis. Eur Heart J. 2025.
9. Kline JA, Mitchell AM, Kabrhel C, Richman PB, Courtney DM. Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism. J Thromb Haemost. 2004;2:1247-1255.