Chapter 104

Chest Pain (Noncardiac)

David Patrick Murphy, William A. Boller

Definition and Epidemiology

Noncardiac chest pain is a recurrent substernal chest pressure or other chest discomfort believed to be unrelated to the heart after a reasonable cardiac evaluation. Because heart disease is the leading cause of death in the United States and because patients are commonly initially seen with chest pain in the primary care setting, it is important to be able to distinguish cardiac from noncardiac causes of chest pain.¹ Research indicates that it is possible to accurately differentiate between the two in most cases. In a study of all patients initially diagnosed with noncardiac chest pain, 93.6% had no evidence of adverse cardiac events, 3.5% had possible evidence of adverse cardiac events, and only 2.8% had a definite cardiac event.²

Nevertheless, symptoms of chest pain are frightening to patients, but reassuringly, most episodes seen in the primary care setting are not of cardiac origin. According to one report, 67% of chest pain diagnoses were a result of musculoskeletal, gastrointestinal, psychiatric, or pulmonary disorders. Only 16% were secondary to cardiac causes of all types, and another 16% were idiopathic.³ Table 104-1 summarizes the data from that study.

TABLE 104-1

Causes of Chest Pain in the Primary Care Setting

Final Diagnosis	Percent of Episodes
Musculoskeletal conditions and chest wall pain	36.2
Gastrointestinal conditions	18.9
Nonspecific chest pain	16.1
Stable angina	10.5
Psychogenic pain	7.5
Respiratory condition	5.1
Nonischemic cardiac condition	3.8
Acute cardiac ischemia	1.5

Interestingly, even when patients have risk factors or indications for invasive diagnostic workups, data consistently show that a large percentage of these patients’ pain still does not have a cardiac cause. For example, when patients undergo cardiac catheterization, approximately 20% to 30% are found to have normal or insignificantly diseased coronary arteries.⁴ In another study, 81% of moderate-risk women with chest pain syndrome were prospectively demonstrated to be experiencing noncardiac discomfort. Of the remainder, only 2.5% of women actually experienced cardiac events.⁵

The correct diagnosis for chest pain is most often obtained with a detailed history, supporting physical examination findings, and an electrocardiogram (ECG) or chest radiograph if indicated. Ruling out cardiac causes of chest pain or other noncardiac life-threatening conditions is an essential first step. The evaluation of cardiac chest pain is discussed separately in Chapter 120.

Immediate emergency department referral or specialist referral is indicated for hemodynamic instability or suspected pulmonary embolism, pneumothorax, esophageal rupture, or aortic dissection.

Pathophysiology

The sympathetic chain, vagus, and phrenic nerves are responsible for carrying pain impulses in the thoracic cage. All the structures in the chest, including the chest wall, esophagus, lungs, heart, and diaphragm, have overlapping innervation. Thus, pain from different organs, including those in the abdomen that abut the diaphragm (liver, spleen, stomach), may have similar referral patterns. In addition, patients may have a difficult time localizing pain from deep structures, whereas diseases involving more superficial structures, such as the chest wall and pleura, are more easily localized. Because there is no sensory innervation in the lung parenchyma, disease involving the alveoli or interstitium does not cause chest pain unless the pulmonary vasculature, bronchi, or pleura is involved.⁶

Clinical Presentation

The history is crucial in determining the differential diagnosis and appropriate management in individuals complaining of chest pain. Careful questioning usually clarifies the cause. Some examples of questions are listed in Box 104-1. The following descriptions should be pursued when the patient is questioned⁷:

Quality: “Can you describe your pain?” Myocardial ischemia typically manifests as a tightness or viselike, constricting, or heavy pressure sensation. On the other hand, pleuritic pain or pain that is positional, sharp, or reproducible with palpation is often not cardiac.

Location: “Where is your pain?” Pain that localizes to a small area of the chest suggests pleural or chest wall involvement. Ischemic pain, however, is often difficult to localize. In fact, in an observational study in patients admitted with chest pain, patients who vocalized larger areas of discomfort were more likely be experiencing a cardiac event than patients who complained of smaller areas.⁸

Intensity: “How severe is your pain?” Pain from an aortic dissection, pneumothorax, or pulmonary embolism all tend to have an abrupt start with the greatest intensity at the beginning. Ischemic chest pain is more gradual, and psychogenic causes of chest pain have a vaguer onset.

Duration: “How long does your pain last?” If the chest pain lasts only seconds or has been constant for weeks, it is unlikely cardiac. Ischemic cardiac pain typically lasts for a few minutes.

Aggravation: “What provokes your pain or makes it worse?” Symptoms related to eating, such as dysphagia, odynophagia, and heartburn, are more suggestive of an upper gastrointestinal cause, whereas chest pain that worsens with physical exertion is usually more reflective of cardiac ischemia. Aggravation of the pain with position changes, deep breathing, or cough is often indicative of a musculoskeletal or pleural disorder.

Alleviation: “What makes your pain better?” Repeated palliation with antacids or food suggests a gastrointestinal source. Esophageal and cardiac causes are generally attenuated with sublingual nitroglycerin. Pain that lessens with rest and cessation of physical activity strongly suggests an ischemic cause.

Box 104-1

Sample Questions for Patients with Chest Pain

• Where is the pain?

• How long have you had the pain?

• Do you have recurrent episodes of pain?

• How long does each episode last?

• What makes the pain better? worse? (breathing? lying flat? moving your arms, neck?)

• How would you describe the pain? (burning? crushing? throbbing? stabbing? knifelike?)

• When does the pain occur? (with exertion? after eating? when moving your arms?)

• Is the pain associated with shortness of breath? (cough? palpitations? nausea and vomiting? fever? leg pain? coughing up blood?)

Modified from Swartz MB, editor: The heart. In Textbook of physical diagnosis: history and examination, ed 5, Philadelphia, 2006, Elsevier.

The patient’s description of his or her symptoms should be viewed in the context of any history of cardiac, pulmonary, psychiatric, or musculoskeletal diseases. It is important to determine whether the patient has a history of similar symptoms or other illness, such as heart disease, pulmonary disease, and diabetes, or a family history of heart disease. Other information to be elicited includes whether the patient has engaged in any recent unusual or strenuous physical activity; whether the patient has experienced any heartburn, difficult or painful swallowing, or water brash; and whether the patient tends to eat before bedtime. The patient should be questioned about whether there has been any blood in the stool or symptoms consistent with anemia. The presence of any recent emotional or psychological stress should also be assessed. Daily caffeine intake and any street or illicit drug use should be discussed as well. Lastly, a thorough review of current medications, both over-the-counter and illicit, should be obtained. All this information may contribute to the decision-making process.⁴

Diagnosis of chest pain in the clinical setting has classically been based on some of the factors listed earlier, including location, description, and precipitants of the pain. This has led to a widely accepted classic angina syndrome, which has been shown to correlate well with underlying coronary artery disease (CAD) in both men and women. However, research indicates that women, elderly individuals, and patients with diabetes with CAD often experience less-typical symptoms, which can result in a missed diagnosis and improper treatment.⁵

Physical Examination

Examination of a patient with chest pain starts with an assessment of his or her general appearance and vital signs. The evaluation must begin with an exclusion of cardiac disease. The general appearance suggests the severity and possibly the seriousness of the symptoms. Abnormalities in vital signs suggest an infectious, pulmonary, cardiac, or malignant process. Hemodynamic instability should prompt immediate referral to the emergency department. The majority of patients with noncardiac chest pain should have normal vital signs. The neck examination should focus on the presence of lymphadenopathy in the cervical chains or supraclavicular fossa. Elevation of the neck veins indicates volume overload and possible heart failure. Tracheal deviation points to a possible pneumothorax.

A general inspection of the chest may reveal a rash, such as the unilateral rash of herpes zoster in a thoracic dermatome. Evidence of trauma may confirm a history of domestic violence or indicate its existence, even if the patient did not discuss it.

Palpation of the chest and range of motion of the upper body may cause chest pain in the presence of costochondritis, musculoskeletal disease, fibromyalgia, rib fracture, or trauma. Dullness to percussion over a portion of the posterior chest indicates either a pleural effusion or a consolidative pulmonary process such as pneumonia.

Auscultation of the lungs may elicit asymmetric breath sounds, pleural friction rub, wheezing, crackles, or absent or decreased breath sounds, all of which should prompt additional investigation with a chest radiograph. The cardiac examination should evaluate for the presence of murmurs, extra heart sounds (S₃ or S₄), or friction rubs.

Examination of the abdomen may reveal tenderness in the epigastric area or right or left upper quadrants, causing irritation of the diaphragm and resultant referred chest pain. Finally, many patients with noncardiac chest pain will actually have completely normal physical examination findings.

Diagnostics

The diagnostic testing options for chest pain are often limited in the primary care setting. If the patient’s chest pain seems cardiac in origin, a 12-lead ECG may demonstrate characteristic abnormalities. Although a normal ECG reduces the likelihood of an acute coronary syndrome by 70% to 90%, it does not completely rule it out. An ECG should always be interpreted in the context of the patient’s history and risk factors for heart disease.⁹

In individuals younger than 40 years, a normal ECG may be sufficient to rule out cardiac disease. However, in older patients or in those with risk factors (e.g., smoking, obesity, diabetes, hyperlipidemia, stress), cardiac enzymes, stress testing, or coronary angiography may also be necessary.² Noninvasive electrocardiographic stress testing is less reliable in women than in men; in women, it is associated with an increased frequency of false-positive results and frequent failure to achieve target heart rates. For these reasons, image-based stress testing has a strong predictive value and may be more diagnostically helpful in women than other noninvasive stress test modalities.⁵

Empirical response to a proton pump inhibitor (PPI) has been shown in studies to be a reasonable first-line means to diagnose gastroesophageal reflux disease (GERD) as a source of chest pain, equal to or better than invasive and expensive testing, such as esophageal pH monitoring, manometry, and upper endoscopy, with sensitivity of 80% and specificity of 74%.¹⁰^,¹¹ A short course of a high-dose PPI twice daily for 1 to 2 months demonstrating good clinical response is sufficient for diagnosis. After this, the dose should be tailored to the lowest once-daily regimen that provides symptom control.¹²

The chest x-ray study is a useful diagnostic tool for detecting cardiac and pulmonary abnormalities. Pulse oximeters should be available to determine the oxygen saturation. On occasion, other studies may be needed, such as an arterial blood gas (ABG) analysis or a complete blood count (CBC) with differential. In most cases, however, a detailed history, physical examination, and possibly an ECG or chest radiograph should give enough information for a hypothesis to be formed regarding the cause of the symptoms.

Diagnostics

Chest Pain (Noncardiac)

Initial