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Autonomic dysreflexia and medical complications of spinal cord injury
Autonomic dysreflexia is an emergency in injuries at T6 and above: a noxious stimulus below the level of injury — usually a full bladder — triggers an uncontrolled sympathetic response and a sharp rise in blood pressure; sit the patient up, find and remove the cause, and only if pressure stays high give a fast-acting drug.
Why it matters in the exam
The picture: a sudden rise in systolic blood pressure of 20 to 40 mmHg above baseline (in a patient whose baseline is often low), a pounding headache, flushing and sweating above the level of injury, pale skin and goose bumps below it, and sometimes bradycardia. The common cause is a full bladder (a blocked catheter), followed by a full bowel; other causes: a pressure injury, an ingrown nail, a fracture, menstruation, labour and sexual activity. Under PVA: sit up and lower the legs, loosen clothing and straps, check blood pressure every 2–5 minutes, check and empty the bladder (with lidocaine gel), then the bowel. If systolic pressure stays at 150 mmHg or more — a short-acting drug (nifedipine or a nitrate; a nitrate is forbidden if a PDE5 inhibitor was taken recently).
Other cardiovascular complications: orthostatic hypotension (abdominal binder, compression stockings, midodrine or fludrocortisone), and venous thrombosis — the risk is very high in the first months, so low-molecular-weight heparin is given with pneumatic compression, usually for 8 to 12 weeks by risk. Temperature regulation is impaired in high injuries — the patient is affected by room temperature. The leading cause of death today is respiratory disease (especially pneumonia); renal failure, formerly the leading cause, has fallen sharply thanks to modern bladder care.
Bone: osteoporosis below the level of injury, and fractures with minor trauma — mainly around the knee (distal femur and proximal tibia); usually managed non-operatively in a padded splint, with care for the skin. Immobilisation hypercalcaemia occurs mainly in young men and adolescents in the first months: nausea, fatigue and behavioural change; treatment — fluids and a bisphosphonate. Heterotopic ossification occurs mainly at the hip. Post-traumatic syringomyelia presents months to years after injury with pain, an ascending level of sensory loss and new weakness, worse with coughing and straining — diagnosed by MRI. Neuropathic pain at and below the level is treated first with pregabalin or gabapentin.
Key points
- Dysreflexia — T6 and above, a trigger below the level, usually the bladder.
- Sit up, loosen, empty; drug if 150 or more.
- Thrombosis prophylaxis 8–12 weeks.
- Fractures around the knee with minor trauma.
- Late new weakness — syringomyelia.
Summary table
| Complication | Clues | Treatment |
|---|---|---|
| Autonomic dysreflexia | T6 and above; rising blood pressure, headache, sweating above the level | Sit up, loosen, empty bladder and bowel; drug if 150 or more |
| Orthostatic hypotension | Dizziness when sitting up | Abdominal binder, stockings, midodrine, fludrocortisone |
| Venous thrombosis | First months | Low-molecular-weight heparin and pneumatic compression, 8–12 weeks |
| Osteoporotic fracture | Swelling around the knee after minor trauma | Padded splint, skin protection |
| Immobilisation hypercalcaemia | Young man, nausea and fatigue | Fluids and a bisphosphonate |
| Syringomyelia | Ascending sensory loss, pain, new weakness | MRI; drainage if worsening |
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Sources
- PVA Consortium for Spinal Cord Medicine: Acute Management of Autonomic Dysreflexia, 2nd edition (2001) — Recognition and stepwise management
- PVA Consortium for Spinal Cord Medicine: Prevention of Venous Thromboembolism in Individuals with Spinal Cord Injury, 3rd edition (2016) — Prophylaxis and duration
- Braddom's Physical Medicine and Rehabilitation, 6th edition (2021) — Medical complications of spinal cord injury
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.