Autonomic

Autonomic Dysreflexia

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Autonomic Dysreflexia

  • Definition
  1. Hypertensive Urgency in a spine injured patient (above T7) resulting from noxious stimuli below the injury
  • Pathophysiology
  1. Underlying spinal cord injury at or above T6 level
  2. Imbalanced reflex sympathetic discharge, leading to Hypertensive Urgency.
  3. Sympathetic spinal reflexes cause sympathetic ganglia activation and direct Vasoconstriction
  4. Inhibitory parasympathetic response cannot reach below the level of the spinal cord lesion.
  • Causes
  • Predisposing Factors (noxious stimuli below spinal cord injury)
  1. Distended Bladder or Urinary Tract Infection (most common)
  2. Constipation
  3. Lower extremity Fracture
  4. Skin dirsuption (e.g. Decubitus Ulcers, Ingrown Toenail)
  • Signs
  1. Systolic Blood Pressure increased 20-40 mmHg over baseline
  2. Altered Heart Rate (typically reflex Bradycardia)
  3. Anxiety
  4. Blurred Vision
  5. Facial Flushing
  6. Headache
  7. Diaphoresis above the level of injury
  8. Piloerection above the level of injury
  9. Cool and clammy below level of injury
  1. Elevate the head of bed to 90 degrees
  2. Monitor Blood Pressure frequently (every 2 to 5 minutes)
    1. Continue to monitor for at least 2 hours after acute episode resolution
  3. Nifedipine IR 10 mg sublingual
  4. Apply Nitroglycerin paste 1 to 2 inches at above above level of injury
    1. Do not use nitrates if recent use of PDE5 Inhibitor (e.g. Viagra)
    2. Other agents to consider if Nitroglycerin is contraindicated
      1. Prazosin or Terazosin
      2. Captopril
      3. Mecamylamine
      4. Diazoxide
      5. Phenoxybenzamine
  • Management
  • Elimination of provocative, noxious stimuli
  1. Remove any tight or restrictive clothing
  2. Place Foley Catheter and perform bladded irrigation
  3. Disimpact patient if indicated
  4. Assess for Pressure Ulcers and other predisposing skin lesions
  • Resources
  1. Christopher and Dana Reeve Foundation: Autonomic Dysreflexia resources and wallet card
    1. http://www.christopherreeve.org/adcard
  • References
  1. Email communication with Christian A. Beebe, M.D., M.B.A.
    1. Dr. Beebe's notes are used with his permission
  2. Cragg (2012) CMAJ 184(1): 66
    1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3255181
  3. EMedicine: Autonomic Dysreflexia in spinal cord injury (accessed 9/16/2015)
    1. http://emedicine.medscape.com/article/322809-overview#showall