Red Flags in Physiotherapy: When to Refer and What Not to Miss
Recognising red flags is one of the most critical clinical skills in physiotherapy. Missing a serious pathology — a spinal tumour, cauda equina syndrome, or cardiac event — can have catastrophic consequences for a patient. This guide covers the key red flags every physiotherapy student and newly qualified clinician must know, with clear guidance on when and how to refer.
What Are Red Flags?
Red flags are clinical features that suggest a potentially serious underlying pathology requiring urgent medical assessment. In physiotherapy, they are most commonly discussed in the context of spinal pain, but red flags exist for every body region.
Red flags do not mean a serious condition is definitely present — they mean the risk is high enough that further investigation is required before continuing physiotherapy treatment. Your role as a physiotherapist is to screen for red flags systematically and refer promptly when they are present.
Spinal Red Flags: The Most Important to Know
Spinal red flags indicate possible serious spinal pathology (fracture, tumour, infection, or inflammatory disease):
- Age of onset < 20 or > 55 years with no previous history of back pain
- Violent trauma (fall from height, road traffic accident)
- Constant, progressive, non-mechanical pain (not relieved by rest or position change)
- Thoracic pain (more likely to indicate serious pathology than lumbar or cervical pain)
- History of cancer — especially breast, lung, prostate, kidney, thyroid (high risk of spinal metastasis)
- Systemic symptoms — unexplained weight loss, fever, night sweats
- Immunosuppression — HIV, long-term corticosteroids, chemotherapy (increased infection risk)
- Prolonged corticosteroid use (osteoporotic fracture risk)
- Intravenous drug use (spinal infection risk)
- Bilateral neurological symptoms — bilateral leg weakness, bilateral pins and needles
Action: Do not treat. Refer to GP or A&E depending on urgency. Document your findings and referral clearly.
Cauda Equina Syndrome: A Medical Emergency
Cauda equina syndrome (CES) is a surgical emergency caused by compression of the cauda equina nerve roots. It requires immediate referral to A&E — delay can result in permanent bladder, bowel, and sexual dysfunction.
Classic features of CES: - Saddle anaesthesia — numbness or altered sensation in the perineum, inner thighs, and buttocks (the area that would contact a saddle) - Bladder dysfunction — urinary retention (most common) or incontinence - Bowel dysfunction — faecal incontinence or constipation - Bilateral leg weakness or neurological deficit - Severe or rapidly progressive low back pain
Important: A patient does not need all of these features for CES to be present. Saddle anaesthesia with any bladder or bowel change is sufficient to warrant immediate A&E referral.
Action: Stop the session. Call 999 or direct the patient to A&E immediately. Document everything.
Cardiac Red Flags
Physiotherapists must be able to recognise cardiac symptoms, particularly during exercise or in patients with cardiac risk factors:
- Chest pain or tightness during or after exercise — possible angina or myocardial infarction
- Unexplained breathlessness at rest or with minimal exertion
- Palpitations or irregular heartbeat during exercise
- Syncope or near-syncope (fainting or feeling faint) during exercise
- Shoulder or jaw pain that is not reproduced by shoulder movement (possible referred cardiac pain)
Action: Stop exercise immediately. If symptoms are acute and severe, call 999. If symptoms are chronic and stable, refer to GP for cardiac assessment before continuing exercise-based physiotherapy.
Other Important Red Flags
Neurological red flags: - Rapidly progressive neurological deficit (weakness, sensory loss) - Upper motor neurone signs (clonus, hyperreflexia, positive Babinski) - Signs of cervical myelopathy (hand clumsiness, gait disturbance, Lhermitte's sign)
Vascular red flags: - Calf pain with swelling, warmth, and redness — possible deep vein thrombosis (DVT) - Intermittent claudication with rest pain — possible peripheral arterial disease - Pulsatile abdominal mass — possible abdominal aortic aneurysm (AAA)
Inflammatory red flags: - Morning stiffness lasting > 45 minutes - Bilateral joint involvement - Systemic symptoms (fatigue, fever, rash) - Raised inflammatory markers (CRP, ESR) on blood tests
Psychosocial red flags (Yellow flags): These predict chronicity and disability rather than serious pathology: - Catastrophising, fear-avoidance beliefs - Low mood or depression - Work dissatisfaction - Passive coping strategies