Which choice is NOT consistent with a limb affected by complex regional pain syndrome?

Which choice is NOT consistent with a limb affected by complex regional pain syndrome?

• A. Osteoporosis
• B. Allodynia
• C. Dermatomal distribution of pain
• D. Atrophy of the involved extremity

Answer: (C)

CRPS is a regional neuropathic pain syndrome that follows an injury to a limb and includes persistent, disproportionate pain with sensory changes (such as allodynia and hyperalgesia), edema and sweating changes, vasomotor instability, and trophic changes like osteoporosis and muscle atrophy. The pain pattern in CRPS is not confined to a single nerve root or dermatomal map; it tends to affect a limb in a regional fashion and can extend beyond a discrete dermatome. A dermatomal distribution of pain points toward nerve-root–based etiologies (like radiculopathy or shingles) rather than CRPS. Therefore, dermatomal pain is not consistent with CRPS, while osteoporosis, allodynia, and involuntary muscle or tissue changes in the affected limb are typical features.

CRPS is a regional neuropathic pain syndrome that follows an injury to a limb and includes persistent, disproportionate pain with sensory changes (such as allodynia and hyperalgesia), edema and sweating changes, vasomotor instability, and trophic changes like osteoporosis and muscle atrophy. The pain pattern in CRPS is not confined to a single nerve root or dermatomal map; it tends to affect a limb in a regional fashion and can extend beyond a discrete dermatome. A dermatomal distribution of pain points toward nerve-root–based etiologies (like radiculopathy or shingles) rather than CRPS. Therefore, dermatomal pain is not consistent with CRPS, while osteoporosis, allodynia, and involuntary muscle or tissue changes in the affected limb are typical features.