What Is Sciatica?
Sciatica is pain that travels along the path of the sciatic nerve — from the lower back through the hip and buttock and down the leg, usually one side only. It's caused by irritation or compression of the sciatic nerve roots.
Symptoms
- Shooting or burning pain from the lower back down through the buttock and into the leg
- Numbness or tingling in the leg or foot
- Weakness in the affected leg
- Pain worsened by sitting, coughing or sneezing
- Typically affects only one side
Common Causes
- Lumbar disc herniation (slipped disc) pressing on nerve root — most common
- Spinal stenosis (narrowing of the spinal canal)
- Piriformis syndrome (piriformis muscle irritating the nerve)
- Spondylolisthesis
- Rarely: tumour, infection or haematoma compressing the nerve
Red Flag Symptoms — Urgent Referral:Loss of bladder or bowel control | Saddle anaesthesia (numbness around the groin/inner thighs) | Progressive neurological weakness | Sciatica with fever and back pain (possible spinal infection).
When Blood Tests Are Ordered
| Test | Purpose |
|---|---|
| ESR & CRP | Elevated if spinal infection or malignancy suspected |
| Full Blood Count | Anaemia or infection |
| PSA (men) | Prostate cancer as a cause of nerve compression |
| Calcium, ALP | Bone metastases |
| Blood glucose | Diabetic neuropathy as differential diagnosis |
FAQs
Does sciatica always need MRI?
No — most cases (80–90%) resolve within 12 weeks without imaging. MRI is reserved for persistent symptoms, red flags, or if surgery is being considered.
What is the best treatment for sciatica?
Staying active (avoid bed rest). NSAIDs for pain. Physiotherapy and targeted exercises. Steroid injections for severe cases. Surgery (microdiscectomy) if neurological deficits progress or persist.
Is heat or ice better for sciatica?
Both can help — ice for acute pain (first 48–72 hours), heat for muscle spasm. Alternate as preferred.
Medical Disclaimer: Sciatica with bladder/bowel changes or bilateral leg weakness is a medical emergency (cauda equina syndrome) requiring immediate hospital assessment.