Autonomic dysreflexia: Difference between revisions
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==Background== | ==Background== | ||
*Syndrome of massive imbalanced reflex sympathetic discharge from strong stimulus below level of spinal lesion | *Syndrome of massive imbalanced reflex sympathetic discharge from strong stimulus below level of spinal lesion | ||
*Carotid and aortic baroreceptors result in strong vagal response with bradycardia and vasodilation above level of injury, but cannot inhibit sympathetics below level of injury - hypertension remains dysregulated by the CNS | *Carotid and aortic baroreceptors result in strong vagal response with bradycardia and vasodilation above level of injury, but cannot inhibit sympathetics below level of injury - [[hypertension]] remains dysregulated by the CNS | ||
*Occurring in patients with spinal cord injury (SCI) above the splanchnic sympathetic outflow (T5-T6) | *Occurring in patients with [[spinal cord injury]] (SCI) above the splanchnic sympathetic outflow (T5-T6) | ||
*Splanchnic innervation from T5-T9 | *Splanchnic innervation from T5-T9 | ||
*Lesions below T6 allow descending inhibitory PSNS control to decrease splanchnic tone, preventing hypertension | *Lesions below T6 allow descending inhibitory PSNS control to decrease splanchnic tone, preventing hypertension | ||
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===Common triggers (due to strong stimuli below level of injury)=== | ===Common triggers (due to strong stimuli below level of injury)=== | ||
*Bladder distension ~80% | *[[urinary retention|Bladder distension]] ~80% | ||
*Bowel distension, fecal impaction ~15% | *Bowel distension, [[fecal impaction]] ~15% | ||
*Pressure ulcers | *[[decubitus ulcers|Pressure ulcers]] | ||
==Clinical Features== | ==Clinical Features== | ||
''Possible to be asymptomatic'' | ''Possible to be asymptomatic'' | ||
*A sudden significant rise in systolic and diastolic blood pressures | |||
**Usually associated with [[bradycardia]] | |||
**SBP >140 mm Hg (in a patient with SCI above T6) | |||
===Unopposed PSNS above lesion=== | ===Unopposed PSNS above lesion=== | ||
*Blurry vision, miosis | *[[blurred vision|Blurry vision]], miosis | ||
*[[Headaches]] | *[[Headaches]] | ||
*[[Anxiety]] | *[[Anxiety]] | ||
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==Evaluation== | ==Evaluation== | ||
==Management== | ==Management== | ||
''Hypertension should abate once offending agent corrected (normal = SBP 90-110 mmHg)'' | |||
#Remove offending agent | #Remove offending agent | ||
#*Check urinary catheter for any blockage or twisting | #*Check urinary catheter for any blockage or twisting | ||
Latest revision as of 23:06, 1 October 2019
Background
- Syndrome of massive imbalanced reflex sympathetic discharge from strong stimulus below level of spinal lesion
- Carotid and aortic baroreceptors result in strong vagal response with bradycardia and vasodilation above level of injury, but cannot inhibit sympathetics below level of injury - hypertension remains dysregulated by the CNS
- Occurring in patients with spinal cord injury (SCI) above the splanchnic sympathetic outflow (T5-T6)
- Splanchnic innervation from T5-T9
- Lesions below T6 allow descending inhibitory PSNS control to decrease splanchnic tone, preventing hypertension
- Medical emergency given dangerous sequelae of elevated blood pressure
Common triggers (due to strong stimuli below level of injury)
- Bladder distension ~80%
- Bowel distension, fecal impaction ~15%
- Pressure ulcers
Clinical Features
Possible to be asymptomatic
- A sudden significant rise in systolic and diastolic blood pressures
- Usually associated with bradycardia
- SBP >140 mm Hg (in a patient with SCI above T6)
Unopposed PSNS above lesion
- Blurry vision, miosis
- Headaches
- Anxiety
- Bradycardia associated with rises in BP
- Profuse sweating/flushing (especially in the face, neck, and shoulders)
- Nasal congestion
Unopposed SNS below lesion
- Pale, cool skin
- Piloerection, goose bumps
Differential Diagnosis
Hypertension
- Hypertensive emergency
- Stroke
- Sympathetic crashing acute pulmonary edema
- Ischemic stroke
- Intracranial hemorrhage
- Preeclampsia/Eclampsia
- Autonomic dysreflexia
- Scleroderma renal crisis
- Acute glomerulonephritis
- Type- I myocardial infarction
- Volume overload
- Urinary obstruction
- Drug use or overdose (e.g stimulants, especially alcohol, cocaine, or Synthroid)
- Renal Artery Stenosis
- Nephritic and nephrotic syndrome
- Polycystic kidney disease
- Tyramine reaction
- Cushing's syndrome
- Obstructive sleep apnea
- Pheochromocytoma
- Hyperaldosteronism
- Hyperthyroidism
- Anxiety
- Pain
- Oral contraceptive use
Evaluation
Management
Hypertension should abate once offending agent corrected (normal = SBP 90-110 mmHg)
- Remove offending agent
- Check urinary catheter for any blockage or twisting
- If cath blocked, gently irrigate bladder with NS at body temp
- If cath is draining, suspect fecal impaction and check rectum for stool with lidocaine jelly lube - gentle disimpaction to follow
- Careful inspection of nonsensate areas to identify the source of painful stimuli
- e.g. catheter, restrictive clothing, leg bag straps, abdominal supports, orthoses
- Check urinary catheter for any blockage or twisting
- Directly lower blood pressure (if #1 fails)
- Place in an upright position to allow gravitational pooling of blood to reduce BP
- BP meds if SBP > 150
- Use short-acting (since offending agent must be corrected); use with caution in CAD
- Nifedipine immediate release
- Nitroglycerine sublingual
Disposition
- Admission
See Also
References
- Gunduz H, Binak DF. Autonomic dysreflexia: an important cardiovascular complication in spinal cord injury patients. Cardiol J. 2012;19(2):215-9.