Autonomic Dysreflexia


Image from The Big Draw 2009
Image from The Big Draw 2009

AD is caused by an irritant below the level of injury, usually related, but not limited to bladder or bowel function.

The most common cause (in 80% of cases) is over distension of the bladder.
This may be due to a blocked urinary catheter or kinked tubing. This is easily rectified by repositioning the tubing or changing the catheter promptly, using a lidocaine based lubricating gel to reduce pain and dull sensations. Over distension may also be due to insufficient frequency of intermittent catheterisation. Other urinary tract triggers include infection, bladder spasm or possibly bladder stones.

The second most common cause (10% of cases) is related to the bowel.
This may be due to constipation (less frequent bowel movements and/or harder faeces/stool), rectal distension (stretching of the back passage), overloaded bowel or haemorrhoids (piles) and anal fissures (small tears in the back passage).

An overloaded rectum should be evacuated (faeces / stool removed) immediately using a lidocaine based lubricating gel and gentle digital stimulation to encourage the rectum to empty. Laxatives should be increased as directed by your doctor and bowel care should be carried out on a daily basis until any constipation has been resolved. Haemorrhoids should be treated with medications available from the pharmacist or on prescription from the GP.

There are many causes of AD, contact your local SCI centre for further advice.

It is sometimes easier to remember causes by the five B’s:


BLADDER – overdistension,blocked catheter, insufficient frequency of Intermittent self-catheterisation (ISC), Urinary tract infection (UTI), stones, bladder spasm.
BOWEL – constipation, rectal distension, overloaded bowel, anal fissure (tear inside rectum), haemorrhoids (piles).
BOILS – skin related – pressure sores, burns and ingrown toenails. Tight clothing, sunburn or frostbite, insect bites, cellulitis (skin infection) or contact with hard or sharp objects may also be causes
BONES – skeletal problems – fractures, hip dislocation, heterotopic calcification (bone overgrowth around joints)
BABIES – sexual/fertility issues – ejaculation, vibrostimulation, period pain, pregnancy/labour. Epididymitis/orchitis (infection in male scrotum)

Sometimes if the cause cannot be found you need to “think outside the box”

  • Gastrointestinal problems/abdominal pain – Duodenal ulcer, cholecystitis, appendicitis, pancreatitis
  • Surgical and medical procedures
  • Deep Vein Thrombosis (DVT) or Pulmonary Embolus (PE) (blood clot in legs or lungs)

Last updated: May 2020