Autonomic Dysreflexia: What You Should Know

Autonomic dysreflexia (AD) is a sudden, dangerous rise in blood pressure that can happen if you have a spinal cord injury at T6 and above (and occasionally as low as T8 or T10). It is your body’s emergency response to a problem below your level of injury — most often a full or kinked bladder, a full bowel, pressure on your skin, or something tight against your body. AD is not “just a headache.” Untreated, it can lead to stroke, seizure, heart problems, or death (per SCIRE / PVA AD guidelines).

The good news: once you and the people who help you know the triggers and the exact steps, most episodes are short and fully preventable.

🚨 Red Flags — When to Seek Emergency Care

Sit up first, then call 911 or go to the ER if:

• Your blood pressure stays high — a systolic reading at or above 150 mmHg, or more than 20 mmHg above your usual baseline (more than 15 mmHg in children) — after you have removed the obvious triggers (bladder, bowel, skin, clothing).
• You have a severe pounding headache, blurred vision or spots, chest pain, trouble breathing, or you feel like you might pass out.
• You have a seizure, confusion, slurred speech, or one-sided weakness.
• You cannot find or fix the trigger quickly and your symptoms are getting worse.

Stay sitting upright — do not lie down. Lying flat can push your blood pressure even higher. Tell the team right away: “I have a T6 (or higher) spinal cord injury and I am having autonomic dysreflexia.” Hand over your wallet card if you carry one — many clinicians outside SCI care have never treated AD (per PVA AD guideline).

Understanding Autonomic Dysreflexia

Your spinal cord injury blocks the signals that normally tell your brain about pain or discomfort below your level. So when something irritating happens down there — a stretched bladder, a hard stool, a sharp object against your skin — your body reacts on its own. Nerves below the injury clamp down blood vessels across a large area of the abdomen (the splanchnic bed), and your blood pressure shoots up (per SCIRE AD handout).

Your brain senses the high pressure and tries to send a calming signal back down to relax those vessels, but the injury blocks it from reaching below your level. So the pressure stays dangerously high until the trigger is removed. T6 is the usual cut-off because that is where the nerves controlling those large abdominal vessels branch off.

Two things make AD easy to miss. First, your normal resting blood pressure after SCI is often low — frequently around 90–110 mmHg systolic. A reading of 120/95 may look “normal” on a chart but be a real emergency for you, which is why knowing your own baseline matters so much. Second, AD can occur with few or no symptoms (“silent AD”) even when your blood pressure is very high — this is common during bladder studies, bowel programs, and sperm retrieval (per MSKTC AD factsheet).

What Triggers It

Almost anything that would cause pain or discomfort if you could feel it can set off AD. Common triggers, in rough order of how often they appear:

• Bladder (the #1 cause): a full bladder, a kinked or blocked catheter, an overfilled or poorly attached leg bag, incomplete emptying, a urinary tract infection, or bladder/kidney stones.
• Bowel: constipation or hard stool, a full or impacted bowel, gas, hemorrhoids, or an overdue bowel program.
• Skin: a starting pressure injury, ingrown toenail, cut, burn, sunburn, insect bite, tight clothing or straps, or a wrinkled sheet or hard object under you.
• Sexual activity: strong genital stimulation, vibratory stimulation, or orgasm (in any gender); a second orgasm can drive blood pressure even higher.
• In women: menstrual cramping, and pregnancy — especially labor and delivery, plus breastfeeding, engorgement, or mastitis after birth.
• Less common: broken bones, heterotopic ossification, blood clots, abdominal problems (gallstones, appendicitis, ulcers), surgery or procedures, and extreme heat or cold.

Daily Prevention Routine

• Follow a strict, predictable bladder program. Empty on schedule even if you “feel fine.”
• Check your catheter and leg bag every morning and before every transfer. Straighten any kinks. Keep the bag below your bladder and not overfull.
• Do your bowel program on the schedule your team gave you, with enough fibre and fluids. Don’t let constipation or impaction build up.
• Do pressure reliefs (push-ups, leans, or tilts) every 15–30 minutes when sitting.
• Check your skin at least twice a day — sacrum, sit bones, heels, and anywhere a strap, seam, or shoe presses — with a mirror or a caregiver’s help.
• Wear loose, non-constricting clothes. Avoid tight belts, leg-bag straps, and shoes that rub.
• Treat skin cuts, ingrown toenails, and infections early, before they grow into triggers.
• Learn your own baseline blood pressure so you can tell when a reading is high for you.
• Keep a “trigger card” in your wallet or phone case listing your usual triggers and your first three steps.

Early Warning Signs & Immediate Response (The Drill)

You may notice one or more of these before — or instead of — a full headache:

• A pounding or throbbing headache that comes on fast
• Flushing, sweating, or blotchy red skin above your injury level (face, neck, shoulders)
• Goosebumps or “hair standing up”; dry, pale, or cool skin below your level
• Nasal congestion or a stuffy/runny nose
• Blurred vision or seeing spots
• Anxiety, restlessness, or a feeling of “impending doom”; a metallic taste
• A slow heart rate (sometimes fast), worsening spasms, or nausea

As soon as you notice any of these, act:

1. Sit up straight (90 degrees) or raise the head of your bed, and lower your legs if you can. Do not lie down.
2. Loosen anything tight: abdominal binder, compression stockings, waistband, leg straps, shoes, catheter tape.
3. Check your blood pressure if you have a monitor. Keep the cuff on and re-check every 2–5 minutes while you work through the steps. Write down the numbers and times.
4. Check the bladder first. Drain the bag, unkink the tubing, or catheterize now. If a catheter is blocked or won’t drain, replace it — don’t keep flushing a bladder that isn’t emptying.
5. Check the bowel next. If it’s full and your blood pressure is settling, do a gentle digital check or your usual bowel routine. Using lidocaine 2% gel first numbs the area and avoids making AD worse (per PVA AD guideline).
6. Check the skin. Look for a new red spot, pressure, ingrown toenail, or anything pressing into you, above and below your level. Shift or remove it.

This sequence — sit up, decompress, then check bladder, bowel, and skin in that order — is the standard first-line response (per SCIRE AD handout). Most episodes settle within minutes once the trigger is gone. If your provider has prescribed a fast-acting medication for AD, know exactly when and how to use it, and keep it with your kit.

If It Keeps Coming Back or Won’t Settle

• Don’t lie flat to “rest.” Stay upright until your pressure is stable.
• Keep checking the less obvious triggers: ingrown toenail, hemorrhoid, new pressure injury, a full leg bag even when the catheter flows, a tight binder.
• Suspect a urinary tract infection if your urine is cloudy, smells bad, or your spasms suddenly worsen — contact your provider the same day.
• If your blood pressure won’t come down or symptoms return with no clear cause, get emergency care. Repeated or “silent” AD can point to bladder stones, a fracture, an abdominal problem, or a change in your bladder/bowel function that needs a workup.
• Do not drive yourself during an episode.

After an Episode — Watch for the Opposite Problem

Once the trigger is fixed (and especially if a medication was used), your blood pressure can swing the other way and drop too low — this is orthostatic hypotension. You may feel dizzy, light-headed, weak, tired, or faint, or have blurred vision when upright (per SCIRE orthostatic-hypotension handout).

• Keep monitoring your blood pressure for about 2 hours after the episode settles.
• If you feel faint or your reading drops low, recline a little and raise your legs until it recovers.
• Report every episode to your provider, even one you fixed yourself — they may adjust your plan.

When to Call Your Doctor or Rehab Team (Non-Emergency)

• You had an episode and aren’t fully sure what triggered it.
• Episodes are happening more often than usual, or are taking longer to settle.
• Your usual bladder or bowel routine suddenly stops working the way it used to.
• You notice new skin breakdown or a change in spasticity that lines up with AD spells.
• You’re planning surgery, a urological procedure, pregnancy, or sperm retrieval (see below).

Special Situations

Surgery, dental work, and procedures. Even though you may not feel pain in the area, anesthesia should still be used to keep AD from being triggered during surgery or invasive procedures (per SCIRE AD handout). Tell every surgeon, anesthetist, and dentist about your AD risk in advance.

Bladder and bowel procedures (cystoscopy, urodynamics, sperm retrieval). These stretch the bladder and bowel and commonly trigger AD. Ahead of time, your team may have you take a recent bowel program, treat any infection, and use numbing lidocaine in the urethra or rectum. Your blood pressure should be watched closely throughout, and you may be offered preventive medication (per PVA AD guideline).

Sexual activity. Strong stimulation and orgasm can raise blood pressure more than they do for people without SCI, and AD may be silent. If you’re prone to it, monitor your blood pressure, stop and follow your AD steps if symptoms start, and re-check within a few minutes of stopping. Talk to your provider about prevention if it’s a regular problem.

Pregnancy, labor, and breastfeeding. If you’re pregnant and at risk for AD, you need a care team that knows SCI. AD during labor can be mistaken for preeclampsia, so it must be sorted out carefully. Spinal or epidural anesthesia is the most reliable way to prevent AD during delivery, even if you can’t feel pain. AD can also be triggered afterward by breastfeeding, engorgement, or mastitis (per PVA AD guideline).

A note on “boosting.” Deliberately triggering AD to raise blood pressure for sports performance is dangerous and can cause uncontrollable, life-threatening spikes. It is banned in competition and should never be done.

Travel, Work, and Community Adaptations

• Always travel with extra catheters, a spare leg bag, gloves, lubricant, and your trigger card.
• Carry an AD emergency kit: a blood pressure cuff, lidocaine/lubricant jelly and gloves for a rectal check, an extra catheter and insertion kit, a bladder irrigation kit, and any AD medication your doctor prescribed (per PVA / Craig Hospital AD materials).
• Brief every new caregiver or support worker on your exact AD protocol on day one — don’t assume they “know SCI.”
• At work or school, keep a small kit in a private spot so you can check and fix triggers quickly.
• On transit or paratransit, plan extra time for a bladder check before the return trip.

Caregiver / Family Quick Reference

• Learn the warning signs and your person’s normal baseline blood pressure.
• If AD starts: sit them upright (never flat), loosen tight clothing, then check bladder, bowel, and skin in that order while monitoring blood pressure every few minutes.
• Wear gloves and use lubricant or numbing jelly for any rectal check, and be gentle — rough stimulation can worsen AD.
• If you can’t find or fix the cause, or the blood pressure stays high, call 911 and say it is autonomic dysreflexia in a person with a high spinal cord injury.
• Keep a simple diary of episodes — symptoms, suspected cause, and what fixed it — to share with the care team.

What Many People Find Helpful

Many people keep a small “trigger card” in their wallet and a photo of their AD steps on their phone, so anyone helping can act fast. Learning your own normal blood pressure early — and writing it on your card — turns a confusing reading into a clear signal.

It’s common to feel that providers outside SCI care don’t recognize AD. Many people find it pays to be a calm, firm advocate: name the condition, hand over the card, and explain that it’s an emergency. If you can’t speak for yourself, a family member who knows your plan can direct your care.

People also notice patterns — sweating that clears when they roll to the other side, a headache every bowel program, spasms that flare with a brewing bladder infection. Noticing the pattern is often the key to preventing the next episode.

Evidence & Sources

Synthesized from the PVA/Consortium for Spinal Cord Medicine Autonomic Dysreflexia clinical practice guideline and consumer materials (2020/2025), MSKTC factsheets, the SCIRE Community autonomic dysreflexia and orthostatic hypotension handouts, and the Craig Hospital AD factsheet (retrieved 2026-06-24). See RESEARCH-SOURCES.md for complete provenance. Primary clinical detail — the response drill, the >20 mmHg-above-baseline definition, the 150 mmHg escalation threshold, and the special-situation guidance — is drawn from the PVA AD guideline, cross-referenced with the SCIRE and Craig handouts.

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You are the expert on your own body. Most people at risk for AD go long stretches between serious episodes once they and their caregivers master prevention and the response steps. Keep this guide — and your AD kit — where you and anyone who helps you can reach them fast.