Red flags for acute back pain include cauda equina symptoms (saddle anaesthesia, bilateral leg weakness, bladder or bowel dysfunction), history of malignancy, unexplained weight loss, fever, immunosuppression, trauma in osteoporotic patients, and age of onset under 20 or over 55 with new symptoms. Any red flag warrants urgent imaging and specialist referral.
See sources cited
- NICE NG59: Low back pain and sciatica
Red flags requiring urgent investigation include cauda equina syndrome and malignancy.