Question 1

What are the cauda equina red flag symptoms requiring urgent referral in back pain?

Accepted Answer

Cauda equina syndrome (CES) is a surgical emergency requiring same-day MRI and neurosurgical referral. Red flags: Bilateral leg weakness or sensory loss; Saddle anaesthesia (reduced sensation around anus, perineum, genitals); Bowel dysfunction — constipation or faecal incontinence; Bladder dysfunction — urinary retention (most common — painless inability to void), incontinence, or altered sensation of fullness; Sexual dysfunction. The GP rule: Ask about bladder, bowel, and saddle sensation at every consultation for back pain. Delay in diagnosis beyond 48 hours dramatically worsens prognosis. Same-day emergency MRI is required to confirm — do not wait for GP to refer via routine pathway.

Question 2

How should acute gout be treated and when should urate-lowering therapy be started?

Accepted Answer

Acute gout treatment: First-line — NSAIDs (naproxen 500 mg BD or indometacin 50 mg TDS) for 5–7 days, or colchicine 500 mcg BD–TDS for 2–5 days (better tolerated, less GI risk than NSAIDs in some patients). If NSAIDs and colchicine contraindicated — prednisolone 30 mg OD for 5 days. Do NOT start or stop allopurinol during an acute attack — it prolongs the attack. Urate-lowering therapy (ULT) — start allopurinol AFTER the acute attack has resolved (usually 2–4 weeks), typically 100 mg OD increasing by 100 mg monthly to target serum uric acid <360 µmol/L. Cover initiation with colchicine 500 mcg BD for 6 months to prevent flares. Lifelong treatment required for recurrent gout.

Question 3

What are the Ottawa knee rules for deciding when to X-ray a knee injury?

Accepted Answer

Ottawa Knee Rules — X-ray required if any of: Age ≥55; Isolated patella tenderness (no other bony tenderness); Fibular head tenderness; Inability to flex knee to 90°; Inability to bear weight both immediately and in the emergency department (4 steps). Sensitivity ~97%, specificity ~48% — designed to safely reduce unnecessary X-rays. If Ottawa rules negative: manage conservatively with PRICE (protection, rest, ice, compression, elevation), analgesia, and physiotherapy referral. If Ottawa rules positive or mechanism of injury concerning: arrange X-ray. MRI is indicated for suspected ligament injury (ACL, PCL, collateral) or meniscal tear.

Test	Indication	When to Order
X-ray lumbar spine	Fracture, deformity	Trauma, osteoporosis risk, structural deformity
MRI lumbar spine	Disc herniation, CES, tumour, SpA	Red flags, neurology, surgical candidate, suspected CES (urgent same-day)
FBC, ESR, CRP	Infection, malignancy, inflammatory	Night pain, fever, weight loss, elevated inflammatory markers
PSA, serum protein EP	Prostate Ca, myeloma	Males >50 with back pain, hypercalcaemia, anaemia
HLA-B27	Axial spondyloarthropathy	Inflammatory back pain + uveitis, psoriasis, IBD, peripheral arthritis
DEXA scan	Osteoporosis	Vertebral fracture suspected, prolonged steroid use, postmenopausal women

Musculoskeletal Medicine

Back Pain

CAUDA EQUINA SYNDROME — 999 / Emergency Referral

Mechanical vs Serious — History Keys

Management — Acute (<6 weeks)

Investigations — When to Order