Chest Pain

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[edit] Chest Pain

Charles Telfer Williams

Pains or discomfort in the chest can be caused by a multitude of ailmentsencompassing the psychiatric, neurologic, respiratory, cardiovascular, musculoskeletal, gastrointestinal (GI), and dermatologic systems. Increasingly good studies delineate guidelines for the assessment of chest pain in the emergency department setting.^[1][2][3] Less is known about chest pain in the ambulatory setting (Table 16-1).^[4][5][6] The STARNET study, which screened for anxiety and panic in ambulatory patients presenting with chest pain, before the physician interview, found that half the patients (25 of 51) had either infrequent panic or panic disorder and that physicians frequently missed these symptoms.^[5]

Table 16-1 Causes of Chest Pain in Ambulatory Setting

Although the diseases that present with chest pain are well described, precise diagnosis is complicated by cultural differences in disease presentation, physiology of pain perception in the chest area, and coexistence of other disease. Given these confounding factors, a simple algorithmic approach to the diagnosis of chest pain is at best a guideline. A careful history and physical examination are essential and can help the physician prioritize disease risks. The first task is to rule out the potentially life-threatening causes: myocardial infarction (MI), unstable angina, dissecting aneurysm, pulmonary embolism (PE), pneumothorax, or the depressed patient with suicidal intent.

[edit] History.

The history starts with a good knowledge of the characteristic symptoms of the different diseases that present with chest pain (Table 16-2). Psychiatric disorders can mimic many of these symptoms, in particular cardiac symptoms. Any evaluation of chest pain should consider anxiety disorders, especially panic attacks, because of their frequency in primary care settings. Panic symptoms include (1) shortness of breath or a smothering sensation; (2) dizziness, unsteady feelings, or faintness; (3) palpitations or accelerated heart rate; (4) trembling or shaking; (5) sweating; (6) choking; (7) nausea or abdominal distress; (8) depersonalization or derealization; (9) paresthesias; (10) flushes or chills; (11) chest pain or discomfort; (12) fear of dying; and (13) fear of “going crazy” or losing control (see Chapter 49 ). Chronic chest pains are unlikely to result from panic but can be caused by other psychiatric illnesses, including anxiety, somatiform disorder, and depression. Patients with recurring or chronic chest pain should be screened for these disorders (see Chapters 48 and 50 ).

Table 16-2 Diseases that Present with Chest Pain

The history should include the patient's risk factors for atherosclerotic disease: personal history of coronary artery disease (angina or prior MI), gender (males are more likely to have disease at a younger age), hypertension, diabetes, high LDL (low-density lipoprotein) or total cholesterol, low HDL (high-density lipoprotein) cholesterol, smoking, family history of premature coronary artery disease (male under age 55, female under 65), and obesity. Many patients with angina or MI, however, have none of these risk factors.✢✢For calculation of risk based on Framingham Study data, visit http://www.biostat.washington.edu/~thomas/CHS/framol.html.Finally, asking about substance use, particularly cocaine, is necessary because cocaine use may cause angina or MI.

[edit] Physical Examination.

The examination can help clarify the differential diagnoses generated by the history. The general appearance of the patient is nonspecific but often is revealing. Cyanosis indicates hypoxemia from abnormal respiratory function (e.g., ventilation/perfusion mismatch) or

low cardiac output. Severe pain is unlikely to signify mild disease. Sweating is often associated with MI. High anxiety levels may be seen in any chest pain presentation but may suggest panic or anxiety disorder.

The vital signs are important in determining the patient's stability. Tachycardia can be associated with anxiety, MI, PE, and pneumothorax. Bradycardia may be seen in healthy normal patients or those with MI. Hypertension may be an underlying or acute condition and is unlikely to help clarify the diagnosis; hypotension is more suggestive of MI (likelihood ratio [LR] 3.1) but may also be seen in patients with PE.^[7] Blood pressures in both arms and a leg should be performed to rule out aortic dissection.

Respirations can be increased in any cause of chest pain but are most likely in pulmonary processes. Respiratory examination may reveal absent breath sounds or a deviated trachea consistent with pneumothorax or tension pneumothorax. Pulmonary friction rubs may indicate a pleural process. Dullness to percussion or increased tactile fremitus may indicate consolidation, as in pulmonary infarction. Fine crackles may indicate heart failure. Tachypnea may be seen with anxiety, MI, PE, pneumothorax, pleural irritation, or “splinting” from musculoskeletal injury.

The cardiac examination may be entirely normal in a patient having an acute MI, but a third heart sound is somewhat predictive (LR 3.2).^[7] A new mitral regurgitation murmur may be noted with papillary muscle dysfunction from an MI. A cardiac friction rub suggests pericarditis.

Palpation of the chest wall, shoulders, and abdomen is crucial. If this palpation reproduces the chest pain syndrome, it is likely to be musculoskeletal. The examiner must ensure that palpation is reproducing the pain symptoms, not just causing pain. A way to test this is to inject anesthetic into the pain site; if the pain is alleviated, it is likely musculoskeletal. Likewise, if nitroglycerin eliminates the pain, a cardiac etiology is much more likely. If reproduced by palpation (LR 0.2 to 0.4) or positional (LR 0.3), pain is unlikely to be from an MI. Extremity examination reveals signs of deep venous thrombosis in 50% of patients with PE.

[edit] Electrocardiogram (ECG).

This relatively inexpensive and easily obtained test may be helpful for identifying cardiac disease as well as some pulmonary pathologies (e.g., massive embolism). In a stable patient in whom the pretest probability of cardiac ischemia is low, the physician may consider not obtaining an ECG. Lee et al^[2] identified three criteria that predicted a low probability of MI or unstable angina: (1) sharp or stabbing pain, (2) no history of angina or MI, and (3) pleuritic or positional pain, or pain reproduced by palpation of the chest wall. In patients who met all three criteria (48 of 596), none had MI or unstable angina, and the ECG in 30 (63%) was potentially misleading. Even if these criteria are met, however, an ECG may still be helpful in clarifying other diagnoses.

When reading an ECG, the physician should especially note signs suggestive of MI (ST segment elevation, new Q wave, dysrhythmias), pericarditis (diffuse ST elevation, PR depression), embolism (S1Q3T3, right bundle branch block, R axis, hyperacute P waves), or pneumothorax (change in axis). A normal ECG is fairly reassuring, although 20% of patients with MI have normal ECGs.

[edit] Life-Threatening Causes.

The next step is to stratify the patient according to risk and rule out the potentially life-threatening causes of chest pain: MI, unstable angina, pneumothorax, PE, and aortic dissection. The physician first must determine whether the patient is having an acute MI or unstable angina, which would likely require admission to an intensive care setting; this is more likely than the other diagnoses. After the history and ECG have been obtained, apply the Goldman protocol or modifications of this protocol (see Chapter 13 ) (Fig. 16-1).^[1] This sorts out MI/unstable angina with fairly good accuracy (sensitivity 88.0%, specificity 74.0%) and recommends monitoring in a cardiac care unit (CCU). In a prospective trial this protocol was equal to clinicians in detecting MI (88.0 vs. 87.8%) and superior to clinicians in ruling out MI (74.0 vs. 71.0%). Although the Goldman model identifies the patients needing admission to a CCU, it does not help determine which patients to send home or which to monitor in the hospital. Clinical judgment may still lead the physician to monitor the patient in an inpatient setting and should not be ignored.

Figure 16-1 Goldman protocol in diagnosis of chest pain. MI, Myocardial infarction.

Diagnosing aortic dissection, PE, and pneumothorax is usually aided by a chest radiograph, which can help rule out a pneumothorax and may indicate aortic dissection or pulmonary infarction. Aortic dissection should be suspected in patients with arm/arm or arm/leg blood pressures differences, pain radiating to the back, or a radiograph that shows a widened aorta. A high suspicion for the diagnosis of PE or pulmonary infarction is always required because classic signs (hemoptysis, tachypnea, tachycardia, fever) are not always present. Pneumothorax can often be diagnosed by physical examination, but a chest film during expiration rarely misses significant pneumothorax on careful review.

[edit] Differential Diagnosis And Workup.

Once illnesses requiring the most acute attention have been excluded, the physician should differentiate the other causes of chest pain: cardiac (angina, pericarditis, mitral valve prolapse), GI (gastroesophageal reflux disease [GERD], gastritis, ulcer, hiatal hernia, esophageal spasm), dermatologic (herpes zoster, cellulitis), respiratory (tracheobronchitis, pleuritis, pneumonia, pleural effusion), psychiatric (panic, anxiety, depression, other somatoform disorders), and musculoskeletal (costochondritis, strains, sprains, arthritis, myositis). A physical examination may indicate a musculoskeletal cause. Differentiating angina and GI causes of chest pain may be difficult. Evaluation of overall atherosclerotic risk factors helps to determine whether a cardiac workup should take precedence. In a young patient with few risk factors and atypical chest pain, therapy for GERD or gastritis should probably be done before a cardiac workup. Anxiety may be difficult to sort out but should be kept in the differential diagnosis to prevent misdiagnosis and prolonged workup (Table 16-2).

[edit] REFERENCES