Pain Assessment, Diagnosis, and Clinical Evaluation
Framing the evaluation
Pain is a biopsychosocial experience, so the evaluation must capture mechanism, anatomy, and psychosocial context. Begin by classifying pain as nociceptive (somatic or visceral), neuropathic, nociplastic, or mixed; this drives subsequent testing and treatment. A careful history covers onset, location, quality, temporal pattern, aggravating and relieving factors, associated neurologic or systemic symptoms, prior treatments, function, sleep, mood, and substance use. Screen every new pain for red flags-fever, weight loss, night pain, bowel or bladder dysfunction, saddle anesthesia, progressive weakness, trauma, or cancer history-because these change the urgency of imaging and referral.
The physical examination should be hypothesis-driven: inspection, palpation, range of motion, a focused neurologic exam (strength, reflexes, sensation, gait), and provocative maneuvers such as straight-leg raise or facet loading. Imaging and electrodiagnostics confirm, rather than replace, a clinical diagnosis. Standardized measures (numeric rating scale, DN4 or painDETECT for neuropathic features, PHQ-9, GAD-7, pain catastrophizing scale) add reproducible data, but a pain score alone is a poor outcome measure.
Common exam traps: treating Waddell signs as proof of malingering (they are nonorganic signs, not lie detection); labeling all radiating leg pain as radiculopathy when neurogenic claudication or hip pathology can mimic it; ordering advanced imaging before a red-flag screen; and ignoring functional and psychological contributors.
Worked example: a 68-year-old reports bilateral buttock and thigh pain provoked by walking and relieved by leaning over a shopping cart. Pulses are normal, straight-leg raise is negative, and gait is stooped. This pattern suggests neurogenic claudication from lumbar stenosis rather than vascular claudication; imaging and a walking test help confirm. Rule of thumb: red flags first, mechanism second, measurement third-and always ask what the patient cannot do, not only how much it hurts.