Epidemiology: more likely in complete than incomplete SCI.

Pathology: Individuals with a SCI at or above T6 can get an imbalanced reflex sympathetic surge; the CNS responds to this HTN by sending a strong inhibitory response, but because of spinal cord discontinuity, the response only travels as far as the injury.

Etiology:

• Bladder distension or irritation (UTI, stone, kinked/blocked catheter, instrumentation/ cystoscopy, etc.) is responsible for 75-80% of cases.
• The 2nd most common cause is bowel distension (often due to fecal impaction).

Clinical: > 20/10 rise in BP above baseline, usually associated with bradycardia.

• HPI → HA, blurry vision, fatigue.
• Exam → profuse sweating and flushing above level of lesion, piloerection below the lesion; nasal congestion is a common symptom
• Can lead to ICH, seizures, MI, pulmonary edema, renal insufficiency, retinal hemorrhages because of sustained and severe peripheral HTN.

Management:

• Source control
• Catheterize the patient if no indwelling catheter.
• If catheter in place, check the system for kinks and blockage.
• Check for fecal impaction and disimpact as needed + bowel regimen.
• Examine for pressure ulcers as a possible source.
• If the above measures fail to illicit source, consider work up for PE and surgical abdominal etiologies like appendicitis and biliary disease based on your clinical assessment.
• Consider antihypertensive agents like nitrates or nifedipine, especially in patients with SBP > 150 or signs of end-organ damage (think of as hypertensive emergency).
• Many men with SCI are on erectile dysfunction meds → nitrates are contraindicated
• Patient Education and Prevention → proper bowel (prevent impaction) and bladder (prevent distension) care is required

Bottom Line: Think twice about that elevated BP in T6+ SCI patients.

References

• Krassioukov A, Warburton DE, Teasell R, Eng JJ Spinal Cord Injury Rehabilitation Evidence Research Team. A systematic review of the management of autonomic dysreflexia after spinal cord injury. Arch Phys Med Rehabil. 2009;90:682–695.
• Milligan J, Lee J, McMillan C, et al. Autonomic dysreflexia: recognizing a common serious condition in patients with spinal cord injury.  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3418979/ Can Fam Physician. 2012;58:831–835