Autonomic dysreflexia

§AD:Acute syndrome of massive sympathetic discharge triggered by noxious stimulus in persons with SCI above the level of the sympathetic splanchnic outflow which usually couples with the spinal cord at T6.

§Incidence:48% to 83% in tetraplegia and paraplegia §Mostly not in the first 2 months post injury

§Cause: B labber distension(most common) Pressure sore Bowel impaction Ingrow toenails Tight clothing or shoes Leg bag strap UTI Ueterine contraction during delivery Invasive procedure: Bladder catheterization Rectal stimulation Cystometrography ESWL

§Pathomechanism: The triggering event produce impulses transmitted to dorsal column and spinothlalamic tract Due to the spinal lesion above the sympathetic outflow, inhibitory impulses cannot effectively descend in the sympathetic chain to block the autonomic response The result is peripheral and splanchnic vasoconstriction and the development of acute hypertension, sweating, and piloerection

§Symptoms and signs: With the increase in BP (severe paroxysmal hypertension), the aortic arch and carotid sinus receptor are stimulated, which can result in reflex bradycardia and vasodilation above the level of the lesion The vasodilation is manifested as headache, facial flushing, sweating, and nasal congestion

§Differential diagnosis: Essential hypertension prior to injury Pre-eclampsia in pregnant woman Both are asymptomatic and nonepisodic

§Complications:due to severe hypertension Confusion Visual disturbance Loss of consciousness Encephalopathy ICH Seizure Electrocardiographic change AF Acute myocardial failure Pulmonary edema

§Management: l The first action:upright sitting l Frequently moniter BP and pulse l Quick survey of cause and correct: Bladder distension Rectal impaction Tight clothing l Medication: Rapid-onset short duration antihypertensive (nitrates, nifedipine, prazosin, hydralazine, mecamylamine, and IV diazoxide) 2% nitroglycerine ointment:1 inch skin above the lesion level Acetaminophen:for headache

§Recurrent AD treatment: l Ganglionic blocking agent (guanethidine, mecamylamine, and phenoxybenzamin) l Newer alpha-adrenergic receptor blockers (terazosin) l Pudental nerve blocks, posterior rhizotomy, and cordectomy:obliterate autonomic afferent imput

§Prevention: Proper bladder and bowel management and skin care §Education: Appropriate antihypertensive home medication can be used in emergency Teach the patient how to explain to medical personnel