Chapter 5. Differential Diagnosis

At the completion of this chapter, the reader will be able to:

1. Understand the importance of differential diagnosis.

2. Recognize some of the signs and symptoms that indicate the presence of a serious pathology.

3. Discuss the concept of malingering.

4. Describe why certain signs and symptoms (red flags) require medical referral.

5. Describe the various infective diseases and inflammatory disorders that the orthopaedic clinician may encounter

6. Describe the various neoplastic and metabolic diseases that can impact the orthopaedic patient.

7. Discuss the differences between fibromyalgia and myofascial pain syndrome.

8. List the various systemic or medical pathologies that can mimic musculoskeletal pathology in various body regions.

An important component of the Vision 2020 statement set forth by the American Physical Therapy Association1 is achieving direct access through independent, self-determined, professional judgment and action. With the majority of states now permitting direct access to physical therapists, many physical therapists now have the primary responsibility for being the gatekeepers of health care and for making medical referrals. In light of the APTA's movement toward realizing “Vision 2020,” an operational definition of autonomous practice and the related term autonomous physical therapist practitioner is defined by the APTA's Board as follows:

• “Autonomous physical therapist practice is practice characterized by independent, self-determined professional judgment and action.”
• “An autonomous physical therapist practitioner within the scope of practice defined by the ‘Guide to Physical Therapist Practice’ provides physical therapy services to patients who have direct and unrestricted access to their services, and may refer as appropriate to other health-care providers and other professionals and for diagnostic tests.”2

Through the history and physical examination, physical therapists diagnose and classify different types of information for use in their clinical reasoning and intervention.3 The Guide clearly articulates the physical therapist's responsibility to recognize when a consultation with, or referral to, another health-care provider is necessary.4 This responsibility requires that the clinician have a high level of knowledge, including an understanding of the concepts of medical screening and differential diagnosis. The results of a number of studies have demonstrated that physical therapists can provide safe and effective care for patients with musculoskeletal conditions in a direct access setting.5–7 Indeed, in a study by Childs et al.,8 physical therapists demonstrated higher levels of knowledge in managing musculoskeletal conditions than medical students, physician interns and residents, and most physician specialists except for orthopedists. In addition, physical therapist students enrolled in educational programs conferring the doctoral degree achieved higher scores than their peers enrolled in programs conferring the master's degree.8 Furthermore, licensed physical therapists who were board certified achieved higher scores and passing rates than their colleagues who were not board certified.8

In an effort to aid the differential diagnosis of musculoskeletal conditions commonly encountered by physical therapists, screening tools have been designed to help recognize potential serious disorders (red or yellow flags).9

• Red-flag findings are symptoms ...