# Internal Medicine/Chest Discomfort

Chest discomfort is a prevalent reason for individuals seeking medical attention in both emergency departments (ED) and outpatient clinics. The assessment of nontraumatic chest discomfort poses challenges due to the wide range of potential causes, including a minority that could be life-threatening conditions requiring immediate attention. A practical approach to diagnosing and prioritizing patients with acute chest discomfort involves categorizing them into three main groups: (1) myocardial ischemia; (2) other cardiopulmonary causes, such as myopericardial disease, aortic emergencies, and pulmonary conditions; and (3) noncardiopulmonary causes. While identifying high-risk conditions is crucial during the initial assessment, caution is needed when employing strategies that involve routine and excessive testing to avoid unnecessary investigations that could lead to adverse effects.

## Epidemiology and Natural History

Chest discomfort is one of the top three causes for ED visits in the United States, resulting in 6 to 7 million emergency visits annually. More than 60% of patients with this complaint are admitted for further evaluation, while the rest undergo additional testing in the ED. Ultimately, less than 15% of evaluated patients receive an acute coronary syndrome (ACS) diagnosis, with rates ranging from 10% to 20% in most studies of unselected populations, and potentially as low as 5% in certain studies. Gastrointestinal causes are the most common diagnoses, accounting for the majority (Refer to Fig. 14-1), while life-threatening cardiopulmonary conditions comprise as little as 5%. In some cases of transient acute chest discomfort, ACS or another acute cardiopulmonary cause can be ruled out, but the specific cause remains unidentified. This results in substantial resources and time being spent on evaluating chest discomfort when a severe cause is absent. Historically, however, between 2% and 6% of patients with chest discomfort thought to have nonischemic origins and discharged from the ED were later found to have experienced a missed myocardial infarction (MI). Patients with a missed MI diagnosis face double the risk of death within 30 days compared to those who were admitted.

## Causes of Chest Discomfort

Causes: Various causes contribute to chest discomfort, and their distribution is as follows:
* Gastrointestinal: 42%
* Ischemic Heart Disease: 31%
* Chest Wall Syndrome: 28%
* Pericarditis: 4%
* Pleuritis: 2%
* Pulmonary Embolism: 2%
* Lung Cancer: 1.5%
* Aortic Aneurysm: 1%
* Aortic Stenosis: 1%
* Herpes Zoster: 1%
Cardiopulmonary Conditions: Different conditions present unique clinical features related to chest discomfort:
* Cardiac: Myocardial ischemia and pericarditis lead to stable angina, unstable angina, and MI. Symptoms range from pressure, tightness, and squeezing to pleuritic and sharp pain.
* Vascular: Acute aortic syndrome, pulmonary embolism, and pulmonary hypertension cause sudden-onset tearing or ripping pain, associated with hypertension and signs of increased venous pressure.
* Pulmonary: Pneumonia or pleuritis, spontaneous pneumothorax result in variable discomfort, often accompanied by dyspnea, cough, fever, and rales.
* Noncardiopulmonary: Gastrointestinal conditions like esophageal reflux, spasm, peptic ulcer, and gallbladder disease bring about burning, pressure, and aching discomfort.
Mechanisms of Cardiac Pain
The underlying neural pathways involved in ischemic cardiac pain remain complex. Ischemic episodes are thought to stimulate chemosensitive and mechanoreceptive receptors, triggering the release of substances like adenosine and bradykinin. These substances activate the sensory fibers of sympathetic and vagal afferents. These afferent fibers connect to upper thoracic sympathetic ganglia and thoracic roots of the spinal cord. Impulses then reach the thalamus. Convergence of cardiac sympathetic afferent impulses with somatic thoracic structures within the spinal cord may explain referred cardiac pain. Additionally, cardiac vagal afferent fibers connect to the nucleus tractus solitarius of the medulla, contributing to anginal pain in the neck and jaw.
Pericardial and Other Myocardial Diseases
Inflammation of the pericardium, due to infectious or noninfectious causes, can lead to acute or chronic chest discomfort. The visceral surface and much of the parietal surface of the pericardium lack pain sensitivity. Therefore, pericarditis-induced pain usually stems from associated pleural inflammation. The pain is often pleuritic and worsens with breathing, coughing, or changes in position. Pericardial pain may also be referred to the shoulder and neck due to overlapping sensory supply. Involvement of the pleural surface of the lateral diaphragm can cause upper abdominal pain.
Acute inflammatory and nonischemic myocardial diseases can also cause chest discomfort. Acute myocarditis presents varied symptoms, including chest discomfort arising from inflammatory myocardial injury or increased wall stress due to poor ventricular performance. Takotsubo (stress-related) cardiomyopathy mimics acute MI due to associated ECG abnormalities and elevated biomarkers. Acute aortic syndromes involve acute aortic diseases related to aortic wall media disruption. Aortic dissection involves a tear in the aortic intima, leading to a "false" lumen. Penetrating ulcers and intramural hematomas are other subtypes.
Pulmonary Conditions
Pulmonary conditions and diseases contribute significantly to chest discomfort:
* Pulmonary Embolism: Pulmonary emboli, sudden in onset, can cause pleuritic chest discomfort. It may result from pulmonary infarction, pulmonary artery distention, or right ventricular wall stress.
* Pneumothorax: Primary spontaneous pneumothorax, though rare, presents sudden-onset symptoms with mild dyspnea. Secondary spontaneous pneumothorax is more severe, occurring in patients with underlying lung disorders.
* Other Pulmonary Parenchymal, Pleural, or Vascular Disease: Many pulmonary diseases leading to chest pain do so through pleura involvement. Pneumonia, malignancy, and other conditions can cause discomfort that's often difficult to differentiate from other serious causes of chest pain.
Gastrointestinal Conditions
Gastrointestinal disorders are a prevalent source of nontraumatic chest discomfort. Some notable conditions include:
* Esophageal Disorders: Gastroesophageal reflux and motility disorders can mimic angina in pain quality and location. Esophageal spasm can cause intense retrosternal squeezing discomfort, sometimes relieved by nitroglycerin.
* Peptic Ulcer Disease: Often causing epigastric pain, peptic ulcers can radiate into the chest. The pain can be variable and may extend to the scapula or shoulder.
Musculoskeletal and Other Causes
Various musculoskeletal and other conditions can lead to chest discomfort:
* Costochondritis: Tenderness at the costochondral junctions can cause localized chest pain.
* Cervical Radiculitis: Prolonged or constant aching discomfort in the upper chest and limbs can result from cervical radiculitis, exacerbated by neck motion.
* Other Musculoskeletal Causes: Compression of the brachial plexus by cervical ribs, tendinitis, bursitis, or even herpes zoster can cause chest discomfort.
Emotional and Psychiatric Conditions
Emotional and psychiatric conditions can also manifest as chest discomfort:
* Approximately 10% of patients presenting with acute chest discomfort have a panic disorder or related condition.
* Symptoms include chest tightness, anxiety, and difficulty breathing.

## Management

Chest discomfort is a common presenting symptom in medical practice, often causing concern due to its potential association with serious underlying conditions. When evaluating patients with acute nontraumatic chest discomfort, the primary goals are to assess the patient's clinical stability and determine the likelihood of a life-threatening cause of the discomfort. This initial assessment is crucial, as it helps clinicians prioritize care and diagnostic strategies.
History and Initial Assessment
* History as a Diagnostic Tool: The evaluation of nontraumatic chest discomfort heavily relies on the patient's clinical history and physical examination. Gathering a detailed history allows clinicians to form an initial clinical impression and assess the likelihood of serious cardiopulmonary issues. Key aspects of the history include the quality, location, radiation, pattern, and associated symptoms of the pain.
* Quality of Pain: Understanding the characteristics of the chest discomfort, such as pressure, sharpness, or pleuritic nature, can provide valuable clues to the diagnosis. Specific pain qualities can be associated with different conditions, including ischemic heart disease, pericarditis, pulmonary embolism, and more.
* Location of Discomfort: The location of chest discomfort, whether substernal or localized in other areas, can further guide the diagnostic process. Radiation of pain to various parts of the body, such as the arms, shoulders, neck, or jaw, may indicate specific conditions.
* Pattern of Discomfort: The pattern of chest discomfort, including its onset, duration, and exacerbating or alleviating factors, can help clinicians differentiate between different causes. Understanding how pain changes with activity or rest is particularly informative.
* Provoking and Alleviating Factors: Patients often describe how their discomfort is affected by various factors, such as physical activity, eating, or changes in body position. Recognizing these provoking and alleviating factors can aid in diagnosis.
* Associated Symptoms: Symptoms accompanying chest discomfort, such as diaphoresis, dyspnea, nausea, fatigue, or syncope, provide additional information for assessment. Some of these symptoms may serve as anginal equivalents and suggest cardiopulmonary involvement.
* Past Medical History: Patients' past medical history is essential for assessing risk factors for coronary atherosclerosis and other conditions that may predispose them to specific disorders. It can also offer insights into connective tissue diseases, depression, or prior panic attacks.
Physical Examination
* General Appearance: The patient's general appearance can offer initial clues about the severity of their condition. Signs such as anxiety, pallor, cyanosis, diaphoresis, or specific body habitus can be indicative of acute cardiopulmonary disorders.
* Vital Signs: Measuring vital signs, including heart rate, blood pressure, respiratory rate, and oxygen saturation, is crucial in assessing hemodynamic stability and identifying conditions like acute MI with cardiogenic shock or pulmonary embolism.
* Pulmonary Examination: A thorough examination of the lungs can help identify primary pulmonary causes of chest discomfort, such as pneumonia, pneumothorax, or left ventricular dysfunction leading to pulmonary edema.
* Cardiac Assessment: Cardiac evaluation includes examining jugular venous pulse, auscultating for heart sounds, and assessing for murmurs, friction rubs, or signs of pericardial inflammation. Specific findings can indicate conditions like pericarditis or mechanical complications of MI.
* Abdominal and Extremities Assessment: Localizing tenderness in the abdomen can suggest gastrointestinal causes, while vascular pulse deficits may be indicative of chronic atherosclerosis or acute limb ischemia. Sensory deficits in the extremities may be related to cervical disk disease.
Electrocardiography (ECG)
ECG is a critical tool in the evaluation of nontraumatic chest discomfort. It helps identify patients with ongoing ischemia and secondary cardiac complications. Specific ECG findings, such as ST-segment elevation or depression, are essential for diagnosis. However, ECG sensitivity for ischemia can be poor in some cases, highlighting the importance of serial testing.
Chest Radiography
Chest radiography is commonly performed when patients present with acute chest discomfort. While findings are often unremarkable in ACS, it can help identify pulmonary processes like pneumonia, pneumothorax, or pulmonary edema. Additionally, it can assist in detecting aortic dissection or pericardial calcification.
Cardiac Biomarkers
Laboratory testing, particularly cardiac troponin measurement, plays a pivotal role in diagnosing MI. High-sensitivity troponin assays enable the early detection of myocardial injury, aiding in accurate diagnosis and risk stratification. The pattern of troponin release and its association with ischemia is crucial for diagnosis.
Integrative Decision-Aids
Clinical algorithms and decision-aids are utilized to assist in the evaluation and management of patients with nontraumatic chest discomfort. These tools help estimate the probability of ACS diagnosis or major cardiac events during short-term follow-up. Decision-aids incorporate various factors, including symptoms, age, risk factors, ECG findings, and troponin levels, to guide patient management.
Coronary and Myocardial Stress Imaging
For patients with intermediate or undetermined risk after initial assessment, diagnostic coronary imaging with techniques such as coronary computed tomographic angiography (CTA) or stress nuclear perfusion imaging is recommended. Patient characteristics, history, and preferences influence the choice between these diagnostic tests.

## Pathways for Acute Chest Discomfort

To efficiently manage patients with nontraumatic chest pain, many medical centers implement critical pathways in dedicated chest pain units. These pathways aim to triage high-risk conditions promptly, accurately identify low-risk patients for observation or early testing, and reduce unnecessary testing and hospitalizations through accelerated diagnostic protocols.

## Outpatient Evaluation of Chest Discomfort

Chest discomfort is also prevalent in outpatient settings. While the diagnostic principles remain consistent with the ED, the pretest probability of acute cardiopulmonary causes is lower. As a result, outpatient testing emphasizes history, physical examination, and ECG findings. High clinical suspicion of ACS warrants referral to the ED for further evaluation.