Differentiating Chest Pain

Despite technological advances, a thorough history and physical examination remain the most important components of the evaluation process. The authors detail the clinical findings associated with various cardiac and noncardiac etiologies.

By Nasir Hussain, MD, and Bernard Karnath, MD

Chest pain is one of the most common chief complaints in the acute care setting. The initial approach to evaluating chest pain includes ruling out life-threatening causes such as acute coronary syndromes, aortic dissection, pulmonary embolism, tension pneumothorax, and esophageal perforation. Because heart disease is the leading cause of death in the United States, ruling out a cardiac etiology is an important step in the workup of patients presenting with acute chest pain. Other possible causes include gastroesophageal, pulmonary, and musculoskeletal conditions.

While technological advances in recent years have greatly improved diagnostic accuracy, a thorough history and physical examination remain the most important components in the evaluation process. It is imperative to obtain as many details about the pain as possible, including its onset, location, duration, radiation, quality, and exacerbating and relieving factors. A detailed history sets in motion further diagnostic testing and management decisions (see table below).

In this article, we will discuss the key clinical features that will help the clinician to differentiate the common causes of acute chest pain, with emphasis placed on the history and physical examination.
 

CARDIAC CAUSES

The cardiac causes of acute chest pain can be divided into ischemic and nonischemic conditions (see table below). Ischemic causes include coronary artery disease, aortic stenosis, hypertrophic cardiomyopathy, and Prinzmetal's angina. Nonischemic causes include dissecting aortic aneurysm, pericarditis, and mitral valve prolapse. During the history, it is important to identify cardiac risk factors, such as hypertension, diabetes, hyperlipidemia, smoking, and a family history of early heart disease.

Coronary artery disease. Angina pectoris is defined as chest pain of cardiac origin caused by an imbalance between myocardial oxygen supply and demand. Patients frequently describe the discomfort as a heavy pressure or squeezing that is usually brought on by exertion. Angina pectoris is considered unstable if it is new in onset and severe (at least Canadian Cardiovascular Society class III), if it occurs at rest and usually lasts more than 20 minutes, or if previously diagnosed angina is increasing in frequency, duration, or severity. Associated symptoms include diaphoresis, nausea, vomiting, and weakness. Chest pain and diaphoresis are the two most common symptoms of acute myocardial infarction (MI).

The Levine sign may also be an indication of ischemic pain. This sign is present if the patient places a clenched fist over the sternum when describing the chest pain. The presence of cardiac risk factors, while useful in evaluating asymptomatic patients, is a poor predictor of acute coronary syndromes in the emergency department. The presence of chest pain usually outweighs such risk factors.

One study evaluated the frequency of symptoms among 88 patients who presented with acute MI and found that 78% reported diaphoresis, 64% reported chest pain, 52% reported nausea, and 47% reported shortness of breath. However, it should be noted that up to 25% of all MIs may go unrecognized by the patient, only to be discovered during routine ECG testing. These unrecognized MIs may be silent (asymptomatic), or they may present with atypical symptoms that the patient does not equate with heart disease.

Aortic stenosis. Possible causes of aortic stenosis include a congenital bicuspid valve, aortic sclerosis, and rheumatic fever. Concomitant coronary artery disease is frequently present in patients with aortic sclerosis. The chest pain of aortic stenosis is typically exertional. Symptoms of heart failure may also be present. Syncope is a late symptom and is also typically exertional.

Physical examination reveals a loud systolic ejection murmur, best heard at the second right intercostal space, that radiates to the carotid regions of the neck. The intensity of the murmur does not correlate with the severity of the aortic stenosis. In patients with significant aortic stenosis, the carotid upstroke is usually weak and delayed, but it may be normal or near normal in patients with hypertension and elderly patients with noncompliant arteries. There is also a palpable left ventricular heave at the apex and a palpable thrill over the second right intercostal space.

Hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy is characterized by left ventricular hypertrophy without an antecedent cause. When this condition was first described, the emphasis was on the left ventricular outflow obstruction, but it is now clear that fewer than 50% of patients demonstrate outflow tract gradient. The most common symptoms of hypertrophic cardiomyopathy are dyspnea and chest pain. The dyspnea results from diastolic dysfunction as a result of reduced compliance of the left ventricle. Syncope is also a symptom; typically, it occurs after exertion.

Physical examination findings include a loud systolic murmur that increases with Valsalva's maneuver, a loud S4, a bifid carotid pulse, and a triple apical impulse due to a palpable presystolic S4 and a midsystolic dip in left ventricular pressure. The chest pain associated with hypertrophic cardiomyopathy may be similar to angina in presentation.

Prinzmetal's angina. Prinzmetal's angina is also known as variant angina and occurs as a result of coronary vasospasm. It is more common in women under age 50, and there tends to be a circadian variation in presentation, with most attacks occurring between midnight and 8 a.m., sometimes awakening patients from sleep. The patient may have recurrent, ischemic-like chest pain that differs from typical angina in that it is more likely to occur at rest than with exertion. The ECG may show ST-segment elevations or depressions with chest pain, and coronary spasm may be evident during angiography.

Dissecting aortic aneurysm. Patients with aortic dissection typically complain of acute severe anterior chest pain that radiates to the upper back region. Patients who have hypertension and who are more than 50 years old are at risk for dissection. Patients with Marfan's syndrome and pregnant women may present with aortic dissection at a younger age. Type A dissection occurs in the ascending aorta; type B dissection occurs just distal to the left subclavian artery. Aortic dissection may cause acute MI, especially when it involves the right coronary ostium.

Physical examination may reveal a murmur of aortic insufficiency. Unequal, decreased, or absent peripheral pulses may be present in 50% of patients. Depending on the location, severity, and progression of the dissection, patients can present with stroke, paraplegia, abdominal pain, dyspnea, dysphagia, hoarseness, aortic insufficiency, and pericardial tamponade.

Pericarditis. Pericarditis can occur as a result of viral infection, autoimmune disease, malignancy, uremia, or radiation. It can also occur post-MI (Dressler's syndrome). The viruses most commonly implicated are the coxsackieviruses and the echoviruses. Tuberculosis is another infectious cause of pericarditis. The chest pain of pericarditis is frequently pleuritic in nature. The pain is usually alleviated by leaning forward while sitting and exacerbated by lying down. Fever commonly accompanies the pain.

Pericarditis can frequently result in pericardial effusion. On physical examination, a friction rub is heard on cardiac auscultation.

Mitral valve prolapse. Patients with mitral valve prolapse can present with chest pain. Most patients are thin females. The pain is usually sharp in quality and located at the apex, and it rarely resembles classic angina. Other associated symptoms include dyspnea, fatigue, and palpitations. The pain can be reduced by lying down. Physical examination reveals a late systolic murmur preceded by a midsystolic click, best heard at the apex, that is accentuated when the patient stands.
 

GASTROINTESTINAL CAUSES

According to one study, gastrointestinal disease is the most common cause for which patients are admitted to a coronary care unit to have MI ruled out, accounting for 42% of all cases of chest pain. Common gastrointestinal causes of acute chest pain include esophageal perforation, esophageal spasm, and reflux esophagitis. Other possible causes include peptic ulcer, pancreatitis, and cholecystitis.

Esophageal perforation. Iatrogenic instrument damage, forceful vomiting, or diseases of the esophagus such as esophagitis or neoplasm may cause esophageal perforation. Patients with esophageal perforation complain of sudden, severe, constant pain from the neck to the epigastrium that is worsened by swallowing. Physical examination may reveal neck swelling and subcutaneous emphysema, evident as palpable cutaneous crepitations as free air enters the mediastinum and surrounding tissues. Pleural effusions may also be present.

Esophageal spasm. The pain of esophageal spasm is often confused with ischemic cardiac chest pain because it too is relieved with nitrates. However, unlike cardiac chest pain, the chest pain of esophageal spasms is not related to exertion. Swallowing extremely hot or cold substances often precipitates episodes of chest pain due to spasm.

Reflux esophagitis. The chest pain associated with reflux esophagitis is often described as a burning sensation, frequently referred to as heartburn or pyrosis. It is aggravated by lying down, and it is worse after meals. Other associated symptoms of reflux esophagitis include chronic cough and dysphagia. Patients may also report the regurgitation of bitter gastric contents into the mouth.
 

PULMONARY CAUSES

Common pulmonary causes of acute chest pain include pleuritis, spontaneous pneumothorax, and pulmonary embolism. Other possible causes include pneumonitis, bronchitis, and intrathoracic neoplasm. Chest pain associated with pulmonary disease is frequently described as pleuritic in nature, which implies that the pain varies with the respiratory cycle and is frequently exacerbated during inspiration and coughing. Pleuritic chest pain is typically sharp and unilateral.

Pleuritis. Pleuritis is caused by acute pleural inflammation, usually as a result of lower respiratory infections, although other causes such as autoimmune disease are possible. The pain is sharp and made worse by coughing, deep breathing, or movement. A pleural friction rub is commonly heard on auscultation.

Spontaneous pneumothorax. The chest pain associated with a spontaneous pneumothorax is usually sudden in onset and sharp in nature. It may radiate to the ipsilateral shoulder. Most patients have associated dyspnea. Spontaneous pneumothorax can occur in persons with underlying pulmonary disease such as emphysema. The typical patient is a tall, thin, male smoker. Physical examination reveals the absence of breath sounds and hyperresonance of the affected hemithorax.

Pulmonary embolism. The possibility of pulmonary embolism is suggested when a high-risk patient presents with acute onset of dyspnea and pleuritic chest pain. Severe hypoxia may be present. Risk factors for pulmonary embolism are summarized in Virchow's triad, which includes venous stasis (from prolonged travel or bed rest, for example), hypercoagulability (from pregnancy, malignancy, or estrogen therapy, among other possible causes), and endothelial damage (from recent surgery or trauma, for example).

Most pulmonary embolisms arise from venous thromboembolisms in the lower extremities. One study found that the commonest symptoms include dyspnea (73% of patients), pleuritic pain (66%), cough (37%), lower extremity edema (28%), and hemoptysis (13%). Physical signs included crackles on lung auscultation (51%) and tachycardia (30%).
 

MUSCULOSKELETAL CAUSES AND HERPES ZOSTER

According to one study, musculoskeletal (or chest wall) pain accounted for 28% of all causes of chest pain in patients admitted to a coronary care unit where MI was ruled out. Chest wall pain is usually sharp and more defined than vague. Musculoskeletal causes of acute chest pain include costochondritis (Tietze's syndrome), rib fracture, and myalgia. Palpation of the chest over the affected area may reproduce the pain. Passive spinal movements such as flexion, extension, and rotation of the thoracic spine are also helpful in reproducing musculoskeletal pain. Costochondritis is caused by inflammation of the costochrondral junction.

Herpes zoster can present as acute chest pain. The pain may occur before the vesicular eruption is present, thus making the diagnosis difficult. The pain associated with zoster is usually described as a burning sensation. It has a unilateral dermatomal distribution.
 

COMMON PROBLEM

Chest pain is a common problem in the acute care setting. Life-threatening causes of chest pain must be quickly differentiated from other less serious causes. The history and physical examination remain the front line of evaluation. After initial risk stratification, focused diagnostic testing usually confirms the etiology of chest pain and helps direct management.

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