For the professions of physical and occupational therapy the concepts associated with and use of the term differential diagnosis are still evolving and under debate. A recent editorial describes diagnosis in physical therapy as complex and controversial, with diverse views existing.¹ For physical therapists (PTs), the guiding premise is that the differential diagnostic process fits within the Patient/Client Management Model described in the Guide to Physical Therapist Practice² (Figure 7-1) and within The Guide to Occupational Therapy Practice.³ The therapist attempts to organize the history and physical examination (including tests and measures) findings into clusters, syndromes, or categories. There are certain clusters of findings that suggest the presence of disease or an adverse drug event and warrant communication with a physician. There are other symptoms and signs that are consistent with conditions that still fit into the older disablement framework. In the world today, the model of choice of all therapists is the World Health Organization (WHO) International Classification of Functioning, Disability and Health (ICF), which moves away from the consequences of disease classification to a health focus classification. Thus a shift in how one looks at disease and its impact on health and wellness not only has changed the words used by therapists but also incorporates external societal limitations that our clients face.⁴ These changes do not affect the way a therapist should medically screen before formulating a clinical diagnoses based on movement dysfunction. These conditions are inherent in the interrelationships among impairments, functional or activity limitations, and participation in life and are appropriate for physical or occupational therapy interventions.²,³,⁵,⁶

Figure 7-1 Patient/client management model. (Adapted from American Physical Therapy Association: Guide to physical therapist practice. *Phys Ther* 81:43, 2001, with permission of the American Physical Therapy Association.)

The process of differentiating the cluster of findings that warrant communication with a physician regarding concerns about a patient’s health status compared with those that do not will be called Differential Diagnosis Phase 1.⁷ In this scenario a physician will ultimately diagnose the patient’s illness, but the PT’s and occupational therapist’s (OT’s) examination findings and subsequent patient referral contribute to the diagnosis being generated. For many of these illnesses, the use of advanced imaging, laboratory testing, and/or tissue biopsy is necessary for the diagnosis to be made.⁸ Numerous examples exist in Physical Therapy Journal and Journal of Orthopaedic and Sports Physical Therapy of published case reports and case series describing such action taken by PTs.

If the decision is reached that the symptoms and signs do fall within the scope of practice of PTs and OTs, a second level of differential diagnosis occurs. Now the therapist attempts to categorize the examination findings into the specific diagnostic categories that will specifically guide the choice of treatment interventions and the development of a prognosis. This second level of diagnosis is called Differential Diagnosis Phase 2⁷ and is the focus of Chapters 8 and 9. Figure 7-2 illustrates where Differential Diagnosis Phase 1 and Phase 2 fit into the Patient/Client Management Model.

Figure 7-2 Patient/client management model showing Differential Diagnosis Phase 1 and Phase 2. (Modified from Umphred DA [Chair]: Diagnostic Task Force, State of California, 1996–2000, California Chapter of American Physical Therapy Association.)

The purpose of this chapter is to discuss the medical screening components associated with Differential Diagnosis Phase 1, including identification of patient health risk factors, recognition of atypical symptoms and signs, review of systems, and within-systems review. Methods to collect this information during a patient examination are also presented. The critical importance of therapists developing these visual and analytical skills is that they can lead to identification of the differences between direct causation of movement dysfunction pain syndromes arising from disease versus a system causation that may or may not be directly connected to a specific disease. The therapist referral often plays a critical role in providing the doctor the patient behaviors observed as system causation with or without a disease classification. Patient case scenarios are used to illustrate the important medical screening principles.

Differential diagnosis phase 1: medical screening

The Guide to Physical Therapy Practice²^,⁹ and The Guide to Occupational Therapy Practice³ clearly describe the therapists’ responsibility to refer patients/clients with health concerns to other practitioners. The emphasis of the following discussion is detecting clinical manifestations that suggest the specific need for physician intervention. Typically the initial warning signs associated with these scenarios include a recent onset or exacerbation of symptoms such as pain, weakness, numbness, dizziness, falls, confusion, and so on—common complaints of patients with neurological disorders. Therapists may also detect symptoms or signs unrelated to the primary medical neurological condition but that could be related to an existing comorbidity or a medication side effect. In addition, a general health and wellness screen may reveal a need for a psychological, dermatological, or other nonneurological medical consultation.

As opposed to Phase 2, the goal of Differential Diagnosis Phase 1 is not to formulate a specific diagnosis on the basis of these clinical manifestations. A therapist’s Phase 2 diagnosis is primarily a group of motor behaviors representing movement dysfunction and how it limits independence in life activities and an individual’s ability to participate in life. The Phase 1 process identifies signs and symptoms that are health or disease and pathology driven and, when they have been identified, directs a referral to a medical specialist. In fact, providing a specific diagnosis or labeling a cluster of examination findings when referring a patient to a physician because of health status concerns (e.g., peptic ulcer disease, endometriosis, new or progressive neurological problems) could place the therapist outside the scope of his or her practice. Having the ability to formulate such a specific systemic, neurological, or visceral disease or pathology diagnosis is not necessary to meet the responsibilities described in the Guides to Practice. Once the therapist’s concerns have been communicated, it is then up to the physician to diagnose the presence of such disease entities.

The purpose of the therapist’s medical screening is to (1) identify existing medical conditions, (2) identify symptoms and signs suggesting that an existing medical condition may be worsening, (3) identify neurological manifestations that suggest an acute or life-threatening crisis, and (4) identify symptoms and signs suggestive of the presence of an occult disorder or medication side effect. This medical screening has always taken place within the clinical framework of PTs’ and OTs’ practices, but as practitioners become more autonomous, this screening must become more comprehensive, requiring tools and documented evaluation results. Figure 7-3 is an example of an examination scheme leading to the decision to treat the patient, to treat and refer the patient, or to refer the patient. Phase 2 may also include the decision to refer the patient to another practitioner (e.g., dietician, social worker, clinical psychologist) for services augmenting the therapy or to social programs such as wellness clinics that will encourage the patient to participate in movement activities even though he may need individualized therapeutic intervention. The following material focuses on the components of this scheme most directly related to the medical screening process leading to a patient referral.

Figure 7-3 Patient examination scheme. (Taken from notes from course by W. G. Boissonnault, 1998.)

Identifying patients’ health risk factors and previous conditions

Owing to the considerable overlap in symptomatic presentation of impairment-related conditions and those requiring physician examination, identifying existing health risk factors for occult diseases is important. Numerous factors have an effect on the patient’s risk for compromised health status, including age, sex, race, occupation, leisure activities, preexisting medical conditions, medication usage (over-the-counter and prescription drugs), tobacco use, and substance abuse or the interaction of some of these conditions, and family medical history.

Of these, a personal history of a current or recent medical condition, current medication use, and a positive family history (e.g., mother and aunt with a history of breast cancer, father diagnosed with prostate cancer at the age of 58 years) are the most relevant risk factors for the potential presence of an occult condition. For example, the history of a previous episode of depression significantly increases the risk of a second episode compared with the risk that someone who has never had an episode of depression will have his or her first such episode.¹⁰ The greater the number of existing risk factors, the more vigilant the therapist should be for the presence of warning signs suggestive of disease and the more extensive the other medical screening components will need to be. Those increased risk factors, whether within one system or multiple systems, can lead to clinical behaviors that are the summation of the systems problems and their interactions that affect movement. Physicians should be able to depend on the therapist to recognize these interactive symptoms and refer the patient back to either the referring physician or to another specialist.

There are different methods to collect this medical history and patient profile information, including a review of the medical record and use of a self-administered questionnaire, depending on the practice setting and patient population. Figure 7-4 is an example of a self-administered questionnaire that could be completed by the adult patient, a family member, or a caregiver. As noted in Figure 7-3, a quick scanning review of this information should occur, if possible, before the patient interview is begun. The therapist will have a head start in organizing the history and physical examination, knowing what to prioritize and at least initially what parts of the examination can be deemphasized. The utility and accuracy of a self-administered questionnaire in patient populations germane to therapists’ practice, similar to the one illustrated in Figure 7-4, have been described, with the conclusion that such a tool can be a valuable adjunct to the oral patient interview.¹¹

Figure 7-4 Self-administered questionnaire to collect medical history information. (Modified from Boissonnault WG, Koopmeiners MB: Medical history profile: orthopaedic physical therapy outpatients. *J Orthop Sports Phys Ther* 20:2–10, 1994, with permission of the Orthopaedic and Sports Sections of the American Physical Therapy Association.)

Affirmative answers to previous or current illness questions should direct the therapist to consider what the potential impact may be on the patient’s symptoms, choice of examination and treatment techniques, rehabilitation potential, and risk for additional illness. For example, the presence of existing chronic kidney disease (e.g., renal failure) should alert the therapist to numerous potential complications including patient fatigue, weakness, and impaired concentration, all of which could interfere with rehabilitation efforts. Chronic renal failure is also marked by paresthesia and muscle weakness, which could mistakenly be associated with other neurological conditions. Renal osteodystrophy is yet another complication associated with chronic renal failure. The concern of compromised bone density should direct the therapist to use techniques that carry a reduced risk of skeletal injury. A series of follow-up questions for the affirmative answers will assist the therapist in determining the relevance (if any) of each item (see Figure 7-5 for examples of follow-up questions for selected information categories).

Figure 7-5 Potential follow-up questions for affirmative answers on the self-administered questionnaire. (From W. G. Boissonnault, course notes, 1998.)

Having the self-administered questionnaire completed before the scheduled time of the initial visit will improve the therapist’s efficiency. Mailing the questionnaire to the patient before the visit or having the patient arrive 10 to 15 minutes before the appointment would allow for the form’s completion without taking time away from the actual examination itself. Once the questionnaire has been completed, taking 1 to 2 minutes to scan it before the interview should be all that is necessary for the therapist to begin formulating questions and organizing the physical examination. The inability of the patient to recall information or complete the questionnaire may be another sign that medical clearance is necessary before progression to Phase 2.

Symptomatic investigation of functional restriction

The chief presenting symptoms or functional restriction typically provides the reason for therapy services being sought and can provide the initial warning sign(s) of potential medical issues needing to be addressed. Despite pain not typically being the chief complaint of many patients with primary neurological conditions, a relatively mild pain is often the initial complaint associated with a serious pathological condition; a dull diffuse ache is often the initial presenting complaint associated with tumors of the musculoskeletal (MSK) system.¹² This relatively minor complaint can easily be overlooked by therapists working with patients who have neurological involvement and signs and symptoms (e.g., weakness, numbness) that are much more debilitating and cause more functional limitations than the pain complaints do. Although investigating pain complaints may not be the initial priority for these therapists, at a later visit such questioning is very important, especially if it continues, increases in intensity, shifts, or enlarges its region with no causation. Effective medical screening involves the interpretation of a patient’s description of symptoms, functional limitations, and the corresponding physical examination findings. Descriptions of symptoms associated with neuromusculoskeletal impairments (loss or abnormality of physiological, psychological, or anatomical structure or function) generally reveal a fairly consistent and predictable pattern of onset and change over a defined period of time. In addition, the neurological and MSK impairments noted during the physical examination should match with the functional limitations described by the patient or the caregiver. If these expectations are not met, it does not necessarily mean the patient has cancer or an infection, but doubt should be raised on the therapist’s part whether therapy is indicated.

Patients many times are not aware that presenting symptoms or signs suggest a condition better addressed by a physician as opposed to a PT or an OT. For example, Mr. S. had a cerebrovascular accident 6 months ago with resultant mild residual left hemiplegia. At the time of discharge from rehabilitation services he was independent in all activities of daily living, but residual left upper extremity weakness remained. When visiting his internist for a routine checkup, he complained that over the prior 3 weeks he had lost some functional skills and was having difficulty with self-care. The physician then referred Mr. S. to the therapy clinic for evaluation and treatment. Mr. S. states he has been less active and just needs some help regaining his motor function. During the history taking he states that he is experiencing a deep, dull, aching sensation in the lower lumbar spine and right buttock. He assumes it has developed as a result of his inactivity and thus saw no reason to bother the physician with this problem. As Mr. S. continues to describe his difficulties, he also notes a constant deep ache in the right shoulder that he relates to increased use of his right arm to compensate for the left arm weakness. The physical examination of the low back, pelvis, and right shoulder reveals that the existing symptoms do not vary with active or passive range of motion, resisted testing, or postural holding. In addition, quantity of motion is normal for these regions and motor programming appears intact. At this point the therapist cannot explain the symptoms from an impairment standpoint; therefore, depending on other examination findings, including the patient profile and medical history, communication with the internist may be warranted. The following information describes some of the subcategories associated with symptom investigation.

Location of symptoms

A body diagram can be a valuable tool to document the location of symptoms expressed verbally or nonverbally by patients with identified neurological deficits. Besides pain and altered sensation, patterns of abnormal tone, asymmetrical posturing, and areas of weakness can also be noted on the body diagram (Figure 7-6). Numerous body structures are potential pain generators, including visceral structures. Figure 7-7 and Table 7-1 illustrate local and referred pain patterns from various visceral organs. Although the presented pain patterns illustrate those most commonly noted, clinicians should be aware of other potential patterns. For example, ischemic heart disease—the complaint of left chest wall and left upper extremity pain, pressure, or tightness—is not the classic presentation for women and many of the elderly. Besides what is noted in Figure 7-7 and Table 7-1, pain from the heart can also be experienced in the right shoulder or biceps, jaw and tooth, epigastric, and interscapular regions.¹³^,^13a

TABLE 7-1

VISCERAL PAIN PATTERNS

STRUCTURE	SEGMENTAL INNERVATION	POSSIBLE AREAS OF PAIN REFERRAL
PELVIC ORGANS
Uterus including uterine ligaments	T10-L1, S2-4	Lumbosacral junction
		Sacral
		Thoracolumbar
Ovaries	T10-11	Lower abdominal
		Sacral
Testes	T10-11	Lower abdominal
		Sacral
RETROPERITONEAL REGION
Kidney	T10-L1	Lumbar spine (ipsilateral)
		Lower abdominal
		Upper abdominal
Ureter	T11-L2, S2-4	Groin
		Upper abdominal
		Suprapubic
		Medial, proximal thigh
		Thoracolumbar
Urinary bladder	T11-L2, S2-4	Sacral apex
		Suprapubic
		Thoracolumbar
Prostate gland	T11-L1, S2-4	Sacral
		Testes
		Thoracolumbar
DIGESTIVE SYSTEM ORGANS
Esophagus	T6-10	Substernal and upper abdominal
Stomach	T6-10	Upper abdominal
		Middle and lower thoracic spine
Small intestine	T7-10	Middle thoracic spine
Pancreas	T6-10	Upper abdominal
		Lower thoracic spine
		Upper lumbar spine
Gallbladder	T7-9	Right upper abdominal
		Right middle and lower thoracic spine, including caudal aspect scapula
Liver	T7-9	Right middle and lower thoracic spine
Common bile duct	T6-10	Upper abdominal
		Middle thoracic spine
Large intestine	T11-12	Lower abdominal
		Middle lumbar spine
Sigmoid colon	T11-12	Upper sacral
		Suprapubic
		Left lower quadrant of abdomen
CARDIOPULMONARY SYSTEM
Heart	T1-5	Cervical anterior
		Upper thorax
		Left upper extremity
Lungs and bronchi	T5-6	Ipsilateral thoracic spine
		Cervical (diaphragm involved)
Diaphragm (central portion)	C3-5	Cervical spine

Modified from Boissonnault WG, Bass C: Pathological origins of trunk and neck pain, I. Pelvic and abdominal visceral disorders. J Orthop Sports Phys Ther 12:192–207, 1990, with permission of the Orthopaedic and Sports Sections of the American Physical Therapy Association.