Michael J. Amirian, MD
Patrick J. Shenot, MD, FACS
BASICS
DESCRIPTION
• Autonomic dysreflexia (AD) occurs in patients with spinal cord lesions at and above the 6th thoracic level (T6)
• Potentially life-threatening condition in response to noxious stimuli
– Genitourinary cause is the most common trigger for AD
– Bladder distention, instrumentation of the urinary tract, and UTI are the most common causes to trigger AD
• Rapid, extreme BP elevation, bradycardia, headache, diaphoresis, sweating, nausea, and piloerection
EPIDEMIOLOGY
Incidence
Unknown
Prevalence
• ∼85% of quadriplegic and high paraplegic individuals prone to AD in response to noxious stimuli
• More common in men than women
– Due to increased bladder outlet resistance
RISK FACTORS
• Male
• High spinal cord injury (SCI)
Genetics
None
PATHOPHYSIOLOGY
• Activation of sympathetic neurons in lateral horn of spinal cord causing unopposed reflex sympathetic activity
– Stimuli (bladder or bowel distention and pain) cause activation
• Vasoconstriction and subsequent hypertension (HTN)
– In response, vagal nerve triggers bradycardia
• Vagal nerve is able to vasodilate above injury (flushing in face), but vessels below injury remain vasoconstricted
• Other symptoms of sympathetic activation
– Diaphoresis and piloerection
ASSOCIATED CONDITIONS
SCI
GENERAL PREVENTION
• Avoid rapid or prolonged bladder distention
• Maintain regular schedule of bowel emptying
• Monitor for pressure sores
DIAGNOSIS
HISTORY
• SCI or transverse myelitis at T6 or above
• Screen for urologic causes
– Bladder distention
– Recent instrumentation
– Indwelling urethral or suprapubic tube
– Urinary tract infection
– Renal, ureteral, or bladder calculi
– Epididymitis or orchitis
– Ejaculation
– Urodynamic testing
• Nonurologic causes
– Bowel distention
– Pressure sores
– Tight clothing
– Ingrown toenails
– Sexual intercourse
– Pregnancy and labor
• Symptoms may include blurred vision, nasal congestion, anxiety
PHYSICAL EXAM
• BP often severely elevated and often accompanied by bradycardia
– Consider that the resting BP is decreased after SCI (ie, 90/60)
– A normal BP of 120/80 may actually represent HTN in this patient population
– A BP 20–40 mmHg above the patients baseline may be a sign of AD
• Flushing and profuse sweating above level of injury
• Piloerection (“goose bumps” with cold or clammy skin below the level of the SCI)
• Evaluate for noxious stimuli below level of SCI
– Skin
Infection, pressure sores
Ingrown nails
Burns
Tight-fitting clothing
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Urinalysis and urine culture
– Evaluate for infection
– UTI can be a trigger for AD
Imaging
• CT of abdomen and pelvis
– Evaluate for urolithiasis if cause not apparent
Diagnostic Procedures/Surgery
• Urodynamic tests to:
– Evaluate bladder compliance
– Rule out persistently elevated bladder pressures
Pathologic Findings
N/A
DIFFERENTIAL DIAGNOSIS
• Brain stem tumors
• Paroxysmal HTN
• Pheochromocytoma
• Preeclampsia
TREATMENT
GENERAL MEASURES
• Removal of triggering stimulus is the 1st step
– Minimize noxious stimuli below level of injury
– Bladder drainage or bowel decompression
– If present, consider gentle Foley catheter irrigation with no more than 10–20 mL saline to make sure that the catheter is patent
• Monitor BP closely during acute episodes
– BP >150 mmHg requires urgent management to avoid severe complications
• Sitting the patient upright might reduce BP
ALERT
Left untreated consequences of autonomic dysreflexia can cause seizures, intracranial bleeds, hypertensive encephalopathy, and death.
MEDICATION
First Line
• Acute episodes managed with nitrates or arterial dilators under closely monitored conditions
– Nitrates: Sub lingual nitroglycerine, apply 1”, 2% nitro paste
Nitrates should be avoided in patients who may be using PDE-5 inhibitors (sildenafil vardenafil, tadalafil) for erectile dysfunction
– Nifedipine 10 mg PO immediate release form
“Bite and swallow” technique
– Captopril 25 mg SL
– Hydralazine or labet alol 10 mg IV
• Chronic treatment with α-blockers may improve some symptoms of AD (1)[B]
– Doxazosin 2–8 mg PO QD
– Terazosin 2–5 mg PO QD-BID
– Tamsulosin 0.4 mg PO QD
– Alfuzosin 10 mg PO QD
• Appropriate antibiotics if UTI suspected
Second Line
• Phenoxybenzamine 10 mg PO BID
• Botulinum toxin injection into the detrusor
– For patients on intermittent catheterization to decrease bladder pressure
• Botulinum toxin injection into external sphincter
– For patients who void reflexively to decrease voiding pressures
SURGERY/OTHER PROCEDURES
• Sphincterotomy or sphincter stent prosthesis
– Allows reflex voiding with low-pressure bladder emptying into a condom catheter (2)[A].
• Bladder augmentation
– Only in patients with ability to catheterize
• Sacral rhizotomy
– For severe cases (3)[B]
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
N/A
Complementary & Alternative Therapies
N/A
ONGOING CARE
PROGNOSIS
Managed effectively will have little impact on patient
COMPLICATIONS
Intracerebral and subarachnoid hemorrhage
FOLLOW-UP
Patient Monitoring
• Clean intermittent catheterization
– Frequent (at least 4 times daily)
• Regular bowel program
• Assess AD symptoms and BP at every appointment
• Teach SCI patients significance of AD
– Symptoms should prompt patients to empty bladder and bowel
Patient Resources
Christopher & Dana Reeve Foundation Paralysis Resource Center. Autonomic Dysreflexia.http://www.paralysis.org/site/c.erJMJUOxFmH/b.1338071/k.5E45/Autonomic_Dysreflexia.htm
REFERENCES
1. Vaidyanathan S, Soni BM, Sett P, et al. Pathophysiology of autonomic dysreflexia: Long-term treatment with terazosin in adult and pediatric spinal cord injury patients manifesting recurrent dysreflexic episodes. Spinal Cord.1998;36:761–770.
2. Chancellor M, Gajewski J, Ackmain CF, et al. Long-term follow-up of the North American Multicenter UroLume Trial for the treatment of external detrusor-sphincter dyssynergia. J Urol. 1999;161:1545–1550.
3. Hohenfellner M, Pannek J, Bötel U, et al. Sacral bladder denervation for treatment of detrusor hyperreflexia and autonomic dysreflexia. Urology. 2001;58:28–32.
ADDITIONAL READING
Consortium for Spinal Cord Medicine. Acute management of autonomic dysreflexia: Individuals with spinal cord injury presenting to health-care facilities, 2nd ed. Available at http://www.pva.org/site/c.ajIRK9NJLcJ2E/b.6305831/k.986B/Guidelines_and_Publications.htm, Accessed April 8, 2013.
See Also (Topic, Algorithm, Media)
• Autonomic Dysreflexia Image 
• Detrusor-Sphincter Dyssynergia
• Spinal Cord Injury
CODES
ICD9
• 337.3 Autonomic dysreflexia
• 596.89 Other specified disorders of bladder
• 599.0 Urinary tract infection, site not specified
ICD10
• G90.4 Autonomic dysreflexia
• N32.89 Other specified disorders of bladder
• N39.0 Urinary tract infection, site not specified
CLINICAL/SURGICAL PEARLS
• Most common triggers are from the genitourinary system such as bladder distention or instrumentation.
• AD occurs at and above level of T6.
• Chronic treatment with α-blockers may improve some symptoms of AD.
• Sphincterotomy or sphincter stent prosthesis allows reflex voiding with low-pressure bladder emptying into a condom catheter.