Longnecker's Anesthesiology > Part 8. Care of the Chronic Pain Patient > Chapter 91. Common Pain Syndromes Basem Hamid, MD

Central Pain Syndromes

"Central pain is a "deafferentation" pain that can result from any lesion found in the CNS.⁹⁹ Virtually any type of lesion can produce this type of pain, including demyelinating, vascular, infectious, inflammatory, and traumatic. Pain onset may be delayed by several months after the initial insult, reflecting the slow degeneration process within the CNS. Pain usually correlates to the anatomic site of the causative lesion. The pain features are those of neuropathic pain.Sympathetically maintained pain (SMP) is defined as "pain that is maintained by sympathetic efferent innervation or by circulating catecholamines."¹⁰⁴ Thus, SMP is not a clinical diagnosis but rather a pathophysiologic mechanism in chronic pain marked by improvement of pain when sympathetic blockade is performed. When the pain does not respond to sympathetic blockade, it is called sympathetically independent pain (SIP). SMP is thought to be a major culprit in many chronic pain states, such as peripheral and central neuropathic pain syndromes.^105–107Stump pain is a chronic sensation of pain at the site of amputation. It also is referred to as residual limb pain.¹⁴¹ It may occur with phantom limb pain or alone. Several factors may account for stump pain and should be evaluated, including surgical trauma, ischemia, local infection, ill-fitting prostheses, or a painful neuroma formation.The facet joints (zygapophysial or Z joints) are true synovial joints..."