🔑 Key Learning
- Caused by compression/irritation of L4–S1 nerve roots, most often due to a herniated disc
- Presents with shooting or burning leg pain ± lower back pain
- Straight Leg Raise (SLR) is a key clinical test
- Most cases resolve within weeks; refer if pain is severe, persistent, or progressive
- Analgesia: 1st line = NSAIDs (+/- PPI)
🧬 Pathophysiology
Compression of lumbosacral nerve roots (L4–S1) forming the sciatic nerve causes radicular pain into the leg.
Causes
- Herniated disc (most common)
- Spondylolisthesis
- Lumbar spinal stenosis
👀 Clinical Features
- Lower back pain
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Unilateral leg pain: radiates to buttock, posterior thigh, calf or foot
- Pain is often sharp, burning or shooting
- Worse on coughing/sneezing
🧪 Examination Findings
- Dermatomal sensory loss
- Myotomal weakness
-
Reflex changes:
- ↓ knee jerk (L4)
- ↓ ankle jerk (S1)
- Straight Leg Raise (SLR): reproduces leg pain between 30–60°
- Bragard’s test: SLR + dorsiflexion → exacerbates pain if radiculopathy
🧪 Investigations
- MRI lumbar spine: 1st line if neurological signs or considering surgery
- CT spine: useful if bony injury suspected
- STarT Back Tool: 9-item questionnaire to assess risk of long-term disability
💊 Management
-
1st line: NSAIDs (short-term), PPI cover
- Alternative: codeine ± paracetamol (short-term)
-
Do NOT offer:
- Gabapentinoids (ineffective + side effects/harm)
- Opioids (not for chronic sciatica)
- Self-management: Stay active; reassure: often resolves over weeks; avoid prolonged rest
-
Referral:
- 2–6 weeks: if severe pain not improving
- 6+ weeks: intolerable or functionally limiting pain
- Consider spinal injection or decompression if conservative measures fail
📝 Exam Clues & Clinchers
- Burning/shooting unilateral leg pain, often below the knee +/- lower back pain
- O/E: SLR positive at 30–60° + Bragard test positive
- MRI if red flags or neuro deficit present