TY - CHAP M1 - Book, Section TI - Chapter 32. Preexisting Spinal Cord Injury A1 - Bass, Candra Rowell A1 - Kumar, Priya A. A2 - Atchabahian, Arthur A2 - Gupta, Ruchir Y1 - 2013 N1 - T2 - The Anesthesia Guide AB - Spinal cord injury (SCI) is common (˜10,000–11,000 cases per year), occurring usually after traumaDegree of dysfunction is directly related to level of injury, especially severe if above T6Most common site of injury is lower cervical spine or upper lumbar region:Midthoracic injury less common due to rotational stabilization provided by the rib cage and intercostal musclesPathophysiology:Upregulation of acetylcholine receptors from immobilization causes resistance to nondepolarizing neuromuscular blockers and increased potassium release with depolarizing neuromuscular blockers (e.g., succinylcholine)Sympathetic hyperreflexia:Nociceptive afferent circuits rebranch below the lesion and anastomose with sympathetic efferents, especially between T5 and L2Hyperreflexia mostly if lesion above T6, but possible even around T12Higher risk with: Urological surgeryComplete cord sectionChronic painMaximal 1–6 months after injury, but can persist indefinitelySmall stimuli can evoke exaggerated, unopposed sympathetic response: Extreme HTN with reflex bradycardia and other dysrhythmiasHeadache, anxietySweatingFlushing or pallorPiloerectionComplications: Myocardial ischemiaCardiac arrestPulmonary edemaHemorrhagic CVAReduced lower limb blood flow, but increased arterial and venous pooling leads to increased risk of thromboembolic diseaseSpasticity: similar mechanism as hyperreflexiaNatural history of injury:Acute (<3 weeks from injury):Spinal shock: hypotension and bradycardiaLoss of thoracic sympathetic outflow, with vasodilatation and pooling of bloodRelative predominance of vagal stimulation to the heartRetention of urine/feces leading to diaphragm elevation, which may impair respirationHyperesthesia above the lesionReflexes and flaccid paralysis below the lesionIntermediate (3 days to 6 months): Hyperkalemic response to depolarizing NMBChronic (after 6 months):Return of muscle tonePositive Babinski signHyperreflexia syndrome SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/29 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=57260719 ER -