Table 1.

Proposed distinguishing characteristics of primary and secondary musculoskeletal pain.⁵

Clinical characteristic	Secondary musculoskeletal pain* (predominantly nociceptive)	Primary musculoskeletal pain (predominantly nociplastic)
Etiology	Potential or actual tissue damage	Dysfunctional processing of pain and other sensory stimuli without tissue injury
Descriptors	Throbbing, aching, pressure-like	Sharp, shooting, lancinating, burning, aching
Sensory deficits	Infrequent	Common, in nonanatomical distribution
Motor deficits	May have pain-induced weakness	Generalized fatigue common; weakness may be related to deconditioning
Diagnostic tests	Imaging may show structural changes, but specificity is low. Laboratory tests also lack specificity.	Imaging and laboratory tests generally within normal limits; can rule out other sources of pain (eg, inflammatory arthritis)
Hypersensitivity	Uncommon except for hypersensitivity in the immediate area	Common, sometimes diffuse
Pain pattern	Distal radiation uncommon, referred pain if proximal structure involved	More diffuse and variable, not following anatomical referral pattern
Precipitating or relieving factors	Exacerbations less common and often associated with activity	Common, often related to psychosocial stress
Autonomic signs	Uncommon	Signs of autonomic dysfunction may be present
Quality of life changes	Quality of life decrements often less than for neuropathic pain	Quality of life decrements similar to or greater than for neuropathic pain
Concomitant conditions	Generally less psychopathology	Higher rates of psychopathology, cognitive impairment, and other comorbid pain conditions than for nociceptive or neuropathic pain

Categories subject to significant heterogeneity and variability.

^*Includes conditions such as myofascial pain syndromes involving trigger points or abnormal myoelectric activity, inflammatory and noninflammatory arthritis, and soft tissue rheumatic complaints (eg, tendonitis).