Chest Pain-crash_course_internal_medicine

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1. Chest Pain Chest pain is a common cause for admission to hospital. Taking a clear history is essential in making the correct diagnosis. Different diseases present with different types of chest pain.

Differential diagnosis of chest pain Pleuritic chest pain: This is a sharp pain that is worse on deep inspiration, coughing, or movement. The differential diagnosis includes the following:

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Pneumothorax. Pneumonia. Pulmonary embolus (PE). Pericarditis: retrosternal. Bornholm disease (Coxsackie B unilateral infection of respiratory muscles).

Dull central chest pain : The differential diagnosis of dull central pain includes the following:

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Angina: crushing. Myocardial infarction (MI): crushing. Dissecting aortic aneurysm: tearing interscapular pain. Esophagitis: burning. Esophageal spasm. Esophageal tear (Boerrhave's syndrome).

Chest wall tenderness : The differential diagnosis of chest wall tenderness includes the following:

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Rib fracture. Shingles (herpes zoster): pain precedes rash. Costochondritis (Tietze's syndrome). Nerve root compression.

Atypical presentations : (or any of the above) The differential diagnosis in atypical presentations (or in any of the above) includes anxiety and referred pain from vertebral collapse, causing nerve root irritation or intra-abdominal pathology (e.g., pancreatitis, peptic ulcer, or the biliary tree). In addition, any of the above diagnoses can present in an atypical manner. For instance, MI can present as epigastric or jaw pain. For this reason, the most serious causes of chest pain should always be added to the differential diagnosis and considered to avoid missing a potentially life-threatening problem.

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History in the patient with chest pain : A careful history of the chest pain will generally be suggestive of the likely underlying problem. It is important during the history to take note of any procedures that have been done and what doctors the patient has seen over the past few years. In addition, social history (drug use and occupation) and psychiatric history can provide insight into the nature of chest pain (e.g., anxiety disorder, cocaine-induced MI). The focus should then turn to any associated symptoms and risk factors.

What type of chest pain does the patient have? Onset and progression of pain Cardiac ischemic pain typically builds up over a few minutes and may be brought on by exercise, emotion, or cold weather. In angina the pain resolves on resting or with sublingual nitroglycerin (NTG). In unstable angina the pain may come on at rest and commonly waxes and wanes, becoming severe at times. In MI the pain is severe, often associated with systemic symptoms such as nausea, vomiting, and sweating, and lasts for at least 30 minutes. Spontaneous pneumothorax and pulmonary embolism usually causes sudden onset of pleuritic pain (patients often remember exactly what they were doing at the time). Pain that follows an episode of vomiting, especially if hematemesis is present, suggests esophageal disease.

Site and radiation of pain Cardiac ischemia and pericarditis cause retrosternal pain. In ischemia, the pain often radiates to the jaw, neck, or arms, while dissecting aortic aneurysm causes a tearing interscapular pain, and pulmonary disease causes unilateral pain which the patient can often localize specifically. Esophageal disease can also cause retrosternal pain and may mimic cardiac pain. Referred pain from vertebral collapse or shingles will follow a dermatome pattern. A note about shingles: Lesions never cross the midline except in patients with immunocompromise, which may be iatrogenic (e.g., steroid use) or due to another cause. In addition, the pain of shingles can begin before the rash appears. Patients complain of "electrical" type pain. Treatment with acyclovir is effective only if given within 24 hours of the initial rash.

Nature of pain The precise nature of the pain gives important clues as to the underlying diagnosis-for instance, crushing, sharp, pleuritic, burning, or stabbing (see above).

Are there any associated symptoms? Important associated symptoms include:      

Dyspnea: pulmonary embolism, pneumonia, pneumothorax, pulmonary edema in cardiac ischemia, hyperventilation in anxiety. Cough: purulent sputum in pneumonia, hemoptysis in pulmonary embolism, frothy pink sputum in pulmonary edema. Rigors: pneumonia (particularly lobar pneumonia). Calf swelling: has PE arisen from deep vein thrombosis? Bilateral swelling suggests heart failure. Palpitations: arrhythmia can cause angina or result from cardiac ischemia, PE, or pneumonia. Clamminess, nausea, vomiting, and sweating are features of myocardial infarction or massive pulmonary embolism.

Do not forget about anginal equivalents, such as those listed above, or jaw pain/tightness or indigestion. Anginal equivalents may be the only presenting symptoms of an MI, especially in elderly and diabetic patients. When in doubt, get an ECG and cardiac enzymes. Are risk factors present? Important risk factors include:

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Ischemic heart disease: smoking, family history, cholesterol, hypertension, diabetes, male sex, age over 50 years. PE: recent travel, immobility, or surgery, family history, pregnancy, malignancy. Pneumothorax: spontaneous (young, thin men), trauma, emphysema, asthma, malignancy, staphylococcal pneumonia, cystic fibrosis.

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Examining the patient with chest pain : Vital signs are vital and therefore should be checked first. Get in the habit of checking the vital signs yourself to

avoid error. The examination should focus on determining the cause of the pain and then looking for risk factors and consequences of the underlying problem. A schematic guide to examining the patient with chest pain is given in Fig. 1.1.

What is the cause of the pain? Pay particular attention to:

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Pulse: tachycardia or arrhythmia. Blood pressure: discrepancy between left and right arms in aortic dissection. Chest wall tenderness: rib fracture, costochondritis, anxiety, shingles. Chest examination: pneumothorax, consolidation, pleural rub. Cardiac examination: fourth heart sound (PE or MI), rub (pericarditis).

The following risk factors may be present:

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Abnormal lipids: xanthelasma, tendon xanthoma. Nicotine-stained fingers: predisposition to ischemic heart disease. Hot, edematous, tender calf, suggesting deep vein thrombosis. Hypertension: ischemic heart disease.

Also look for signs of venous stasis and arterial insufficiency in the lower extremities. Is there a brown discoloration (hemosiderin staining due to blood pooling) of the ankles? Does the patient have palpable lower extremity pulses.

What are the complications? Complications may include:

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Pulse: arrhythmia, tachycardia. Blood pressure: shock in tension pneumothorax, massive pulmonary embolism, MI. Heart failure: pulmonary edema and 3rd heart sound. Murmurs: acute mitral regurgitation and ventricular septal defect after MI; aortic regurgitation in dissecting aortic aneurysm.

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Investigating the patient with chest pain : All patients with chest pain should have an electrocardiogram (ECG), chest x-ray (CXR), and cardiac enzymes (see Fig. 1.5). Further investigation will be directed by findings in these tests in conjunction with the history and clinical examination. An algorithm for the investigation of the patient with chest pain is given in Fig. 1.2. Electrocardiogram ST depression and elevation (Fig. 1.3) on ECG are suggestive of myocardial ischemia and acute MI, respectively. Changes suggestive of PE are shown in Fig. 1.4. Arrhythmia may also be detected on ECG.

Chest x-ray Pneumothorax, consolidation (pneumonia, PE), widened mediastinum (aortic dissection), pulmonary edema (myocardial ischemia/infarction) and fractured ribs may be detected on CXR. Cardiac enzymes Serial cardiac enzymes should be assessed every 8 hours for 24 hours if MI is considered (see Fig. 1.5). Stress test An exercise test may be diagnostic when angina is suspected. Patients walk, ride a bike, or receive medication to increase the heart rate. These tests are done in conjunction with ECG monitoring, and a rest and stressed echocardiogram may also be used during this exam. Any sign of ischemia, such as ST elevation/depression, a drop in blood pressure, chest pain, or arrhythmia, is grounds for stopping the exam. Of note, exercise stress tests with ECG monitoring have a high false-negative rate in women. Therefore, it is often advantageous for a female patient either to undergo a nuclear medicine test, such as an adenosine/thallium stress test, or to go directly to catheterization. In the adenosine/thallium stress test, the heart is medically stressed and a radiolabeled tracer (thallium or sestimibi) is introduced to detect areas of low flow during stressed conditions.

Coronary angiography Coronary angiography allows direct visualization of the coronary arterial tree. It should be used in severe angina to determine whether angioplasty or coronary artery bypass grafting might be beneficial. Angiography is becoming more and more common as the number of centers with interventional cardiologists increases. Patients with equivocal or positive findings on exercise stress tests, along with those who have "good stories" (i.e., risk factors for coronary artery disease) are taken to catheterization regularly. Patients should undergo catheterization if they have two of the following three characteristics:

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Good clinical picture of angina/MI. Positive cardiac markers (troponin, CK-MB). ST segment changes on ECG or new left bundle-branch block (LBBB).

Arterial blood gases The assessment of arterial blood gases is useful in determining the severity of PE, pneumonia, or pulmonary edema, showing hypoxia and occasionally hypocapnia. In hyperventilation related to anxiety, the pO 2 will be elevated while there will be hypocapnia and a respiratory alkalosis. Ventilation-perfusion scan Ventilation-perfusion scan is used to diagnose PE. In some circumstances (e.g., when there is pre-existing obstructive airways disease) interpretation of this test can be difficult, so pulmonary angiography should then be performed. PE protocol CT can be used in addition to angiography in evaluating the patient with pre-existing pulmonary disease.

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Echocardiogram The presence of a dissecting aortic aneurysm should be confirmed by urgent echocardiography (particularly transesophageal echocardiography) or by computed tomography scan. Urgent echocardiography is now used to help detect cardiac effusions and tamponade. Echocardiography also can be used to assess for possible sequelae of MI, such as myocardial dyskinesia, papillary rupture, or ventricular thrombus. Upper gastrointestinal endoscopy Upper gastrointestinal endoscopy will confirm esophagitis and should be considered when the cause of chest pain is unclear.

Figure 1.1 examining the patient with chest pain

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Figure 1.2 Algorithm for the investigation of the patient with chest pain. (CXR, chest x-ray; ECG, electrocardiogram; V/Q, ventilation-perfusion.)

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Figure 1.3 Causes of ST elevation.

Figure 1.4 Electrocardiogram (ECG) changes associated with pulmonary embolus. Note that sinus tachycardia may be the only abnormality present.

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Figure 1.5 Cardiac enzyme elevation following myocardial infarction. (CK, creatine kinase; Myo, myoglobin; Tn, troponin.)