Introductory Chapter: The Patient Presenting with Chest Pain

*John-Ross D. Clarke*

### **1. Background**

Chest pain is the principal reason for approximately 5% of the emergency department (ED) visits in the United States [1]. It is the most frequent reason for presentation to an emergency facility in men age 65 years and older. In some cohorts, chest pain accounts for up to 16% of ambulance transports and constitutes almost 30% of emergency admissions [2, 3]. In the primary care setting however, less than 1% of visits are for a chief complaint of chest pain [4].

Part of the significance of chest pain as a presenting symptom is its association with potentially life-threatening diagnoses such as: acute myocardial infarction (AMI), pulmonary embolism, and aortic dissection, among others. The challenge for the clinician is the accurate stratification of patients based on risk, and the efficient and cost-effective utilization of resources to establish a diagnosis. The first step in diagnosis is an informed history and physical examination- which is not without limitations even in the most experienced hands [5]. The sections that follow provide a brief insight into the scope of chest pain diagnoses and the value of clinical findings in establishing a diagnosis.

### **2. The differential diagnosis of chest pain**

The differential diagnosis of a patient presenting with chest pain is extensive [6]. A systematic approach is therefore needed to (i) determine the likelihood of an immediately life-threatening cause, (ii) differentiate cardiac from noncardiac etiologies, and (iii) reduce over-diagnosis and thus overutilization of healthcare resources in the subsequent investigation. This approach not only increases the diagnostic accuracy and efficiency of workup, but also leads to better patient and clinician satisfaction [7].

There are innumerable ways of categorizing the differential diagnosis of chest pain. Potential categorization approaches are: (i) cardiac vs. noncardiac etiologies (ii) classifying based on symptom characteristics, (iii) by organ systems and (iv) anatomically (**Figure 1**). An anatomic approach allows for an exhaustive differential diagnosis but does have limitations in refinement based on pre-test probabilitythis subsequent step requires the incorporation of other aspects of symptom presentation [6].

A schema for classifying causes of chest pain anatomically includes structures from the skin to internal organs of the thorax and upper abdomen (**Figure 1**).

**Figure 1.** *An anatomic approach to the differential diagnosis of chest pain.*
