Approach to assessment and diagnosis of chronic pain

Journal of Family Practice,  Oct, 2004  by Stephen Brunton

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* PHYSICAL EXAMINATION

A thorough general physical and neurologic examination is essential for diagnosing chronic pain disorders. The examination should, of course, serve to verify the preliminary impression from the history and guide the selection of laboratory and imaging tests. Appearance, attitude, and behavior can provide important clues to the location and intensity of the pain. Speed of movement, gait, use of assistive devices, grimacing, and rubbing all convey important information. These can be investigated further by pain-provoking maneuvers, including range-of-motion determination. Adaptive behaviors employed by the patient to minimize the pain should be noted. (11,35) The physical examination should include careful examination of the site of reported pain, common sites for pain referral, and common sites of pain in older adults. It should also focus on the musculoskeletal system (eg, myofascial pain, fibromyalgia, inflammation, deformity, posture, leg length discrepancy), as well as the neurologic system (eg, search for weakness, hyperalgesia, hyperpathia, allodynia, numbness, paresthesia, other neurologic impairments). [Evidence level: IIIA. Evidence from respected authorities, based on clinical experience, descriptive studies, or reports of expert committees. Good evidence to support the use of a recommendation; clinicians "should do this air the time." Available at: http://www.guideline.gov/summary/ summary.aspx?ss=15 &doc_id:3365&nbr=2591&string:persistent%20AND%20pain.]

In addition to the general physical examination, the system involving the pain complaint should be closely assessed. The neurologic and musculoskeletal systems also should be assessed in detail generally. The diagnosis of NP particularly relies on the demonstration of sensory abnormalities in the area innervated by the damaged nerve. Patients may have a paradoxical response to different stimulation tests in the same nerve distribution. To identify the sensory abnormalities present, a variety of instruments should be used, such as warm and cold objects for temperature sensation, a camel-hair brush or cotton swab to detect touch or allodynia, and a pin for detecting pain and hyperalgesia. (17) The functional examination of the musculoskeletal system is intended to determine if the pain is associated with specific musculoskeletal function or dysfunction. Examination of the spine serves to identify muscular strain, joint sprain, space-occupying lesions, and fracture. When joint pathology is suspected, range of motion, with assistance if needed, should be assessed. (11,35,36)

* LABORATORY AND DIAGNOSTIC TESTING

As there is no single diagnostic test for pain, laboratory and diagnostic testing serve to confirm or exclude underlying causes, such as rheumatoid arthritis, diabetes mellitus, spinal disorders, HIV, or herpesviruses. In addition, laboratory and diagnostic testing are useful to guide disease-specific treatment. Tests should not be ordered unless their results will affect decisions about treatment. [Evidence level: IIIA. Evidence from respected authorities, based on clinical experience, descriptive studies, or reports of expert committees. Moderate evidence to support the use of a recommendation; clinicians "should do this most of the time." Available at: http://www.guideline.gov/summary/summary.aspx?ss=15&doc_id =3365&nbr=2591&string=persistent%20AND%20pain.]