Approach to Articular and Musculoskeletal Disorders
Musculoskeletal complaints account for >315 million outpatient visits per year and over 20% of all outpatient visits in the United States. The Centers for Disease Control and Prevention estimate that 22.7% (52.5 million) of the U.S. population has physician-diagnosed arthritis and 22 million have significant functional limitation. While many patients will have self-limited conditions requiring minimal evaluation and only symptomatic therapy and reassurance, specific musculoskeletal presentations or their persistence may herald a more serious condition that requires further evaluation or laboratory testing to establish a diagnosis. The goal of the musculoskeletal evaluation is to formulate a differential diagnosis that leads to an accurate diagnosis and timely therapy, while avoiding excessive diagnostic testing and unnecessary treatment (Table 393-1). There are several urgent conditions that must be diagnosed promptly to avoid significant morbid or mortal sequelae. These “red flag” diagnoses include septic arthritis, acute crystal-induced arthritis (e.g., gout), and fracture. Each may be suspected by its acute onset and monarticular or focal musculoskeletal pain (see below).
TABLE 393-1Evaluation of Patients with Musculoskeletal Complaints |Favorite Table|Download (.pdf) TABLE 393-1 Evaluation of Patients with Musculoskeletal Complaints
| Accurate diagnosis |
| Timely provision of therapy |
| Avoidance of unnecessary diagnostic testing |
| Identification of acute, focal/monarticular “red flag” conditions |
| Determination of chronology (acute vs chronic) |
| Determination of the nature of the pathologic process (inflammatory vs noninflammatory) |
| Determination of the extent of involvement (monarticular, polyarticular, focal, widespread) |
| Anatomic localization of complaint (articular vs nonarticular) |
| Consider the most common disorders first |
| Formulate a differential diagnosis |
Despite well-known links between certain disorders and laboratory testing, the majority of individuals with musculoskeletal complaints can be diagnosed with a thorough history and a comprehensive physical and musculoskeletal examination. The initial encounter should determine whether the musculoskeletal complaint signals a red flag condition (septic arthritis, gout, or fracture) or not. The evaluation should proceed to ascertain if the complaint is (1) articular or nonarticular in origin, (2) inflammatory or noninflammatory in nature, (3) acute or chronic in duration, and (4) localized (monarticular) or widespread (polyarticular) in distribution.
With such an approach and an understanding of the pathophysiologic processes, the musculoskeletal complaint or presentation can be characterized (e.g., acute inflammatory monarthritis or a chronic noninflammatory, nonarticular widespread pain) to narrow the diagnostic possibilities. A diagnosis can be made in the vast majority of individuals. However, some patients will not fit immediately into an established diagnostic category. Many musculoskeletal disorders resemble each other at the outset, and some may take weeks or months (but not years) to evolve into a recognizable diagnostic entity. This consideration should temper the desire to establish a definitive diagnosis at the first encounter.
ARTICULAR VERSUS NONARTICULAR
The musculoskeletal evaluation must discriminate the anatomic origin(s) of the patient’s complaint. For example, ...