Autonomic Dysreflexia

Epidemiology

  • Occurs with Spinal Cord Injury Above T6 (see Spinal Cord Injury, [[Spinal Cord Injury]])
    • Lesions Below T6 Do Not Result in Autonomic Dysreflexia, Since Intact Splanchnic Innervation Allows for Compensatory Vasodilation of the Splanchnic Vascular Bed

Physiology

  • Loss of Coordinated Autonomic Responses to Physiologic Demands Placed on the Heart Rate and Vascular Tone
    • Noxious Stimuli Below the Level of Injury Lead to Exaggerated Sympathetic Responses with Resulting Diffuse Vasoconstriction and Hypertension
      • Compensatory Parasympathetic Responses Lead to Bradycardia and Vasodilation Above the Level of Injury: however, this is not sufficient to decrease the hypertension

Diagnosis

  • xxx

Clinical Manifestations

General Comments

  • Relationship of Clinical Manifestations to the Severity of Spinal Cord Injury: severity of spinal cord injury is associated with the severity and frequency of autonomic dysreflexia attacks
  • Triggers of Autonomic Dysreflexia
    • Bladder Distention: common precipitant
    • Bone Fracture
    • Bowel Impaction: common precipitant
    • Decubitus Ulcer
    • Labor/Delivery
    • Medical Procedure
    • Occult Visceral Disturbance
    • Sexual Activity

Cardiovascular Manifestations

  • Bradycardia (see Sinus Bradycardia, [[Sinus Bradycardia]])
    • Epidemiology: common
  • Hypertension (see Hypertension, [[Hypertension]])
    • Epidemiology: common
    • Clinical
      • May Be Severe Enough to Result in Hypertensive Emergency
  • Hypotension (see Hypotension, [[Hypotension]])
    • Epidemiology: may occur in some cases
  • Sinus Tachycardia (see Sinus Tachycardia, [[Sinus Tachycardia]])
    • Epidemiology: may occur in some cases

Dermatologic Manifestations

  • Diaphoresis (see Diaphoresis, [[Diaphoresis]])
  • Flushing (see Flushing, [[Flushing]])
  • Piloerection

Gastrointestinal Manifestations

Neurologic Manifestations

  • Anxiety (see Anxiety, [[Anxiety]])
  • Blurred Vision (see xxxx, [[xxxx]])
  • Headache (see Headache, [[Headache]])

Pulmonary Manifestations

  • Nasal Obstruction
  • Neurogenic Pulmonary Edema (see Neurogenic Pulmonary Edema, [[Neurogenic Pulmonary Edema]])
    • Epidemiology: rare
      • May Occur with Chronic Cervical Spinal Cord Injury Above T6

Prophylaxis

Agents Which Have Been Reported to Prevent Attacks


Treatment

General Measures

  • Determination of Noxious Stimuli Contributing to the Event
    • Foley Catheter (see Foley Catheter, [[Foley Catheter]]): to relieve bladder distention
      • If Already Present, Ensure that the Catheter is Not Obstructed
    • Rectal Exam: to evaluate for fecal impaction
  • Monitoring of Blood Pressure
  • Removal of Tight-Fitting Garments

Anti-Hypertensive Measures/Agents

  • Immediate Upright Positioning: to orthostatically lower blood pressure
  • Short-Acting, Rapid-Acting Anti-Hypertensive Agents are Preferred
    • Nitropaste (see Nitroglycerin, [[Nitroglycerin]])
    • Oral Nifedipine (see Nifedipine, [[Nifedipine]])
    • Sublingual Captopril (see Captopril, [[Captopril]])
    • Intravenous Hydralazine (see Hydralazine, [[Hydralazine]])
    • Intravenous Labetalol (see Labetalol, [[Labetalol]])

References

  • Consortium for Spinal Cord Medicine. Acute Management of Autonomic Dysreflexia. Clinical practice guideline for healthcare providers. 3rd Edition 2016 [MEDLINE]