🚨 Autonomic Dysreflexia
A blocked bladder can kill a patient with a spinal cord injury. The one emergency where sitting the patient UP is the treatment.
🧬 What is actually happening
Below the injury, the body screams. Above it, nobody can hear.
A painful stimulus below the level of injury triggers massive sympathetic vasoconstriction. The brain detects the resulting hypertension and tries to switch it off — but the signal cannot travel back down past the injury. So the constriction continues unopposed while everything above the injury dilates.
🚨 Who is at risk
Spinal cord injury at T6 or above. It usually begins after spinal shock resolves and can recur for life.
This is a true medical emergency. Untreated it causes stroke, seizure, retinal hemorrhage or death.
👀 The split picture — above vs below
The signs divide at the level of injury, and that split is the giveaway.
| ABOVE the injury | BELOW the injury | |
|---|---|---|
| Vessels | Dilated | Clamped shut |
| Skin | Flushed, sweating profusely | Pale, cold, goosebumps |
| Symptom | Pounding headache, blurred vision, nasal congestion | Nothing felt — no sensation |
🚨 The vital signs
BP ↑↑↑ HR ↓ Severe hypertension with bradycardia. A systolic of 200+ is common, and a “normal” 120/80 may already be dangerously high — many people with high spinal injuries run a baseline systolic in the 90s.
Always compare to the patient's OWN baseline. A 40 mmHg rise above their normal is a crisis, whatever the absolute number.
The classic first complaint is a sudden pounding headache. Combined with sweating above the injury and goosebumps below, that is autonomic dysreflexia until proven otherwise.
🩺 What to do — in order
This is one of the few emergencies where the first action is to sit the patient UP, not lay them down. Raising the head uses gravity to drop the blood pressure immediately.
💧 Finding the trigger — most to least common
- Distended bladder — the cause in the large majority. Kinked catheter, blocked tubing, full drainage bag
- Impacted bowel or a needed bowel movement
- Skin — pressure injury, tight clothing, a wrinkle in the sheet, ingrown toenail, burn
- Other — menstrual cramps, labor, infection, a fracture below the level
Never lay the patient flat, and never leave them to go and find help - use the call bell.
When relieving impaction, use lidocaine jelly first and wait. Digital stimulation without it can make the crisis dramatically worse.
If the catheter is blocked, irrigate gently or replace it — do not force.
✅ Prevention is the real treatment
- Bladder program — catheterize on schedule, never let it overfill
- Bowel program — regular, consistent timing
- Skin checks and pressure relief every couple of hours
- Teach the patient and family the signs — they will often recognize it before staff do
- A medical alert card is standard, because many clinicians have never seen it
🎯 NCLEX traps
- Sit them UP — the opposite of most hypotension/shock answers
- Check the bladder first — it is nearly always the cause
- Injury T6 or above
- Hypertension WITH bradycardia — an unusual pairing worth memorizing
- Flushed and sweating above, pale and goosebumps below