Key Points
- Red flags screen for four main serious pathologies: malignancy, fracture, infection, and cauda equina syndrome (CES)
- CES is the most urgent: key features are saddle anaesthesia, bladder/bowel dysfunction, bilateral leg weakness, and loss of anal tone
- Serious pathology accounts for <1% of low back pain in primary care, but >80% of patients have at least one red flag, so clinical judgement and the overall picture matter
- Progressive neurological deficit in the lower limbs warrants urgent assessment regardless of other features
Red Flags by Serious Pathology
Cauda Equina Syndrome (urgent/emergency)
The most time-critical diagnosis. Five key features consistently described in the literature:
