D. Chest Pain

Introduction

Pain has been defined as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage and mediated by specific nerve fibers to the brain where its conscious appreciation may be modified by various factors.” Pain follows the bumps and bruises encountered in daily life, and all persons have experienced unpleasant but innocent headaches, sore throats, and muscle stitches. In contrast, pain that seems to originate in the chest generates far greater concern because it may announce the presence of severe, occasionally life-threatening disease. The new onset of chest pain and what it may connote provokes anxiety and fright; consequently, it is one of the symptoms most likely to cause the victim to seek prompt medical attention.

Because it is a subjective experience and difficult to quantify, epidemiological surveys of the prevalence of chest pain and physiological studies of its mechanisms are limited. The different thoracic and neighboring organs that give rise to chest pain, however, are well described as are the identifying hallmarks of the sensations that are typically produced when certain structures are involved. These characteristic features serve as the basis for the classification of the many different causes of chest pain that are listed in Table 9. The most common of these will be discussed in this chapter.

Myocardial Ischemia

The pain of myocardial ischemia is described first because of its clinical importance, both in terms of its frequency and in terms of its diagnostic and therapeutic implications. Even though the receptors, chemical transmitters, and sensory pathways that mediate cardiac pain are not well understood, the message being sent by the oxygen-deprived heart is clear and needs to be listened to.

Coronary Artery Disease: The pain of myocardial ischemia is believed to be provoked by an imbalance between the oxygen needs of the myocardium and the supply available through the coronary circulation. This explains why the resulting pain has similar features in all circumstances, but is associated with a continuum of myocardial injury that varies from angina pectoris (reversible ischemia) at one end to myocardial infarction (death of heart muscle cells) at the other. The pain of angina pectoris is usually described as an intense “pressure,” “squeezing,” or “constriction,” originating underneath or to the left of the sternum; radiation to the neck or down the inner aspect of one or both arms is common. The pain is usually provoked by exercise, but may accompany heavy meals, excitement, or emotional distress. When angina occurs, the victim is generally forced to stop whatever he or she is doing, and the pain will subside within 2 to 10 minutes; relief can be accelerated by sublingual nitroglycerin. In variant (Prinzmetal’s) angina, the pain occurs at rest rather than during exercise. The pain of acute myocardial infarction is similar in location and radiation to that of angina pectoris, but in contrast, tends to be much more severe, is not relieved by nitroglycerin, and typically requires opiates for control. Important distinguishing features of acute myocardial infarction are the accompanying profuse sweating, nausea and vomiting, and profound weakness; massive myocardial infarction may cause intractable hypotension or pulmonary edema.

The coronary artery vasoconstricting and cardiac stimulating effects of cocaine frequently cause anginal chest pain from myocardial ischemia and occasionally, frank myocardial infarction. Cocaine is a common and frequently overlooked cause of visits to the emergency department for chest pain.

Related Syndromes: The pain of myocardial ischemia has many mimics, some of which arise within the heart and others within nearby organs. The pain of pericarditis occasionally resembles angina pectoris, but more typically is pleuritic in nature (see next section) from involvement of the contiguous pleura; sharp steady pain along the upper ridge of the trapezius muscles is said to be quite specific for pericarditis. The pain of myocardial ischemia may accompany diseases that affect the coronary artery ostia, especially aortic stenosis. Surprisingly, cardiac diseases that spare the coronary arteries also cause pain that mirrors that of myocardial ischemia: nearly 50% of patients with severe mitral valve prolapse, 20% of those with myocarditis, and 10% of those with hypertrophic cardiomyopathy complain of such pain. Dissection of the aorta is always in the differential diagnosis, but can usually be differentiated by its unbearable severity from the moment of onset, and its “tearing” or “ripping” quality that extends up into the neck, through to the back, or down into the abdomen.

As will be described, certain gastrointestinal disorders and psychiatric disorders can also cause pain resembling that of myocardial ischemia. The only pulmonary condition that does so, and rarely at that, is pulmonary hypertension, usually of the primary type.

Pleurisy

One of the most characteristic and easy to diagnose types of chest pain is pleurisy from inflammation or irritation of the parietal pleura, which is innervated by branches of nearby intercostal nerves and, over the center of each hemidiaphragm, by the phrenic nerves. In contrast, the visceral pleura is not innervated by nociceptive (pain) receptors, but owing to the contiguity of the visceral and parietal pleural surfaces, inflammatory processes in the periphery of the lungs often cause the pain of pleurisy by extension across the membranes.

Because most intrapulmonary disorders are apt to be localized within a single lung, pleuritic pain is usually sharply restricted to the ipsilateral chest wall or shoulder, cutaneous areas supplied by the involved intercostal or phrenic nerves, respectively. But perhaps the most singular feature of pleurisy is its unmistakable relationship to breathing movements. The pain may be variously described as “sharp,” “dull,” “achey,” sometimes “burning,” or simply a “catch,” but whatever its designation, it is worsened by taking a deep breath, and either coughing or sneezing causes intense distress. The aggravation by breathing causes patients to seek, find, and remain in the body position that most restricts movement of the affected region.

Infection: The classic cause of pleurisy, which is frequently sudden in onset, is community-acquired pneumonia. Other infectious processes of the lung parenchyma that abut the visceral pleura, such as lung absess, can also cause pleurisy. Infections within the pleural space itself, such as empyema or tuberculous pleuritis with effusion, are obvious causes of pleurisy that is apt to be gradual in onset and lingering.

Noninfectious Causes: A wide variety of noninfectious disorders can cause acute pleurisy by sudden involvement of the pleural surfaces or adjacent lung parenchyma. The most important of these include pulmonary embolism, with or without pulmonary infarction, and spontaneous pneumothorax. Both primary bronchogenic cancer and secondary metastases can involve the pleural surfaces and present with chronic pleurisy. Most of the collagen vascular diseases, but particularly rheumatoid arthritis and lupus erythematosus, can cause pleurisy.

Disorders of the Chest Wall

Inflammation of or trauma to the various components of the chest wall is a common cause of chest pain. Because these structures move during breathing, there may be a “pleuritic” element to the resulting pain. In contrast to classic pleurisy, though, chest wall pain is more limited in its distribution and is nearly always associated with localized tenderness.

Trauma: Probably the most common cause of chest wall pain is trauma. Usually, pain is the aftermath of a remembered injury during a fall, fight, or accident. Occasionally, chest wall pain seems to be spontaneous, but in these instances is probably related to an unrecognized strain or tear of an intercostal muscle or rib fracture during exercise, a bout of coughing, or a forgotten injury.

Other Causes: A peculiar type of chest wall pain occurs from costochondritis, inflammation at one of the costochondral junctions, which is also known as Tietze’s syndrome, or of the costosternal bridges that form the cartilaginous shield of the anterior rib cage. The discomfort is often described as dull with a gnawing aching quality to it. Respiratory movements have surprisingly little effect, and the diagnostic key is the presence of swelling and tenderness at the affected site. Superficial, knifelike pain of intercostal neuritis-radiculitis may cause diagnostic confusion; finding hyperalgesia or analgesia over the involved nerve root helps to define the problem; a day or two later, the diagnosis usually becomes evident with the appearance of the vesicular rash of herpes zoster. A variety of so-called shoulder-arm syndromes have been described; of these, an unrelenting deep pain that begins in the shoulder and then progresses to the arm characterizes the Pancoast syndrome, an uncommon but important presenting manifestation of bronchogenic carcinoma.

Tracheobronchial Disorders

Tracheal pain, usually described as “raw” or “burning,” is felt in the midline anteriorly, from the larynx to the xyphoid; pain from either main bronchus is felt to the left or right of the sternum or in the anterior neck near the midline. Tracheobronchial pain may be exaggerated by deep breaths that seem to “cut off” inspiration. Such pain is found in viral and bacterial tracheobronchitis, less often with a tracheal cancer; in addition, healthy people may experience tracheal pain when exercising in heavily air-polluted environments or in extremely cold air.

Abdominal Disorders

Several gastrointestinal tract disorders, particularly those arising in the esophagus, are established causes of chest pain that may resemble angina pectoris in all respects, including location and radiation, quality, and relief with nitroglycerin. This type of pain may arise from either gastroesophageal reflux or from disorders of esophageal motility, and is said to account for symptoms in 10% to 30% of patients suspected of having angina pectoris but whose coronary arteries are normal by angiography. In a reversal of the phenomenon of certain lung diseases, particularly acute bacterial pneumonia in children, presenting with upper abdominal pain, certain abdominal disorders may present with pain in the lower chest; this confusing situation is most apt to occur with cholecystitis, peptic ulcer disease, and acute pancreatitis.

Psychiatric Disorders

No diagnosis is ever made in many patients who complain of chest pain. In some of these persons psychosocial factors are believed to be important, but an exact causal role is difficult to establish. Certain psychiatric disorders are recognized as causing chest pain that simulates angina pectoris. The most important of these are neurocirculatory asthenia, the hyperventilation syndrome, and panic disorders. The problem, though, is complicated by the fact that patients with documented heart disease may also have panic attacks or other psychiatric disorders; this is particularly true in patients who have coronary artery disease or mitral valve prolapse.

Differential Diagnosis

This brief review highlights not only the many different causes of chest pain, but also that they vary in seriousness from innocent to life-threatening. Thus considerable clinical judgment is required to decide which patients should be further studied and which tests should be used in the evaluation. As stressed in Section A, Approach to the Patient, the workup begins with a thorough medical history. Emphasis should be placed on nuances in the behavior of the pain itself, its quality, location, duration, inciting factors, and relieving measures. Questions should be asked concerning other cardinal symptoms of cardiorespiratory diseases such as dyspnea (Section B), cough (Section C), and hemoptysis (Section E). In this regard, it is worth noting that cardiac causes of chest pain are often accompanied by shortness of breath; but in contrast to many respiratory causes of chest pain and dyspnea, and with the exception of pericarditis, the pain of heart disease does not vary with breathing. Associated systemic features, especially fever, night sweats, weight loss, weakness, and edema, provide important clues that help direct the workup. Similarly, a thorough physical examination may reveal signs of chest wall, pleural, pulmonary, cardiac, or abdominal involvement. Next, depending on the need for additional studies and the examiner’s initial suspicion, either a chest x-ray or electrocardiogram is warranted. At this point, three options are generally available: (1) whether or not the patient can be watched and followed by the primary care physician; (2) whether the workup for pleural effusion, pulmonary mass or parenchymal infiltrate, if shown radiographically, should proceed as outlined in the last three chapters of this monograph; (3) whether the patient should be referred for special diagnosis and treatment, as discussed in the next section, perhaps in a hospital.

When to Refer

Patients with chest pain of cardiac origin may need emergency hospitalization and are likely to require further diagnostic evaluation by a cardiologist for coronary artery disease or valvular dysfunction. This may entail echocardiography, cardiac catheterization, treadmill testing, or coronary angiography with possible angioplasty or stent placement. Consultation with a pulmonologist is needed for patients who might require fiberoptic bronchoscopy, pleural biopsy, or specialized pulmonary function testing, including during exercise. Similarly, if invasive procedures are contemplated to evaluate chest pain of possible esophageal origin or somewhere in the abdomen, referral to a gastroenterologist is warranted. In selected cases of intractable chest pain of presumed psychological origin, referral to a psychiatrist can be helpful.

Medicolegal Concerns

Perhaps the most frequent cause of medicolegal conflict, one that concerns all patients, not just those with chest pain, is failure to document adequately all contact with and advice given to patients. For patients who are seen for new-onset chest pain, particularly if conceivably caused by life-threatening myocardial ischemia or pulmonary embolism, failure to hospitalize and to seek appropriate consultation are grounds for legal action.

Summary

Chest pain is one of the most common medical symptoms. Although most of the time innocuous and often difficult to pinpoint, chest pain must always be thoughtfully considered because it may be the first signal of serious, potentially lethal disease. A careful medical history is the first step in unraveling the mysteries of chest pain. Then, a thorough physical examination and, when indicated, one or two tests, an electrocardiogram and chest x-ray, completes the baseline information necessary to decide what to do next: watch and wait, proceed with management, or refer for specialized evaluation.

References

Murray JF, Basbaum AI. Chest pain. In Murray JF, Nadel JA (eds). Textbook of Respiratory Medicine, 2nd ed. WB Saunders, Philadelphia, 1994, 545-561. Thorough description of the neurobiology of pain and the different clinical types and sources of chest pain.

Crea F, Gaspardone A. New look to an old syndrome: Angina pectoris. Circulation 1997;96:3766-3773. Comprehensive review of the mechanisms and clinical manifestations of this form of myocardial ischemia; 119 references.

Minocha A. Noncardiac pain. Where does it start? Postgrad Med 1996;100:107-114. Nice overview of the many different and sometimes confusing causes of noncardiac chest pain.

Douglas PS, Ginsberg GS. The evaluation of chest pain in women. New Engl J Med 1996;334:1311-1315. An important article that emphasizes the differences in origin and clinical manifestations of coronary artery disease in women.

Wise CM. Chest wall syndromes. Cur Opin Rheumat 1994;6:197-202. Latest and best review of the epidemiology, manifestations and diagnosis of the pain syndromes resulting from disorders of the chest wall.

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