How can I differentiate between sciatica caused by a herniated disc and other potential causes of nerve root pain?

To differentiate sciatica caused by a herniated disc from other causes of nerve root pain, focus on clinical assessment and exclusion of red flag symptoms. Sciatica due to a herniated disc typically presents with radicular leg pain following a dermatomal pattern, often accompanied by neurological signs such as sensory loss, motor weakness, or reflex changes corresponding to the affected nerve root.

Key steps include:

• Assess for red flag symptoms that suggest serious underlying pathology (e.g., cauda equina syndrome, spinal cord compression, tumour, infection) which require urgent referral and imaging rather than assuming a herniated disc ¹,².
• Use clinical history and examination to identify radicular pain characteristics and neurological deficits consistent with nerve root compression, which are common in herniated disc sciatica ¹,².
• Consider risk stratification tools like the STarT Back Screening Tool to assess prognosis and guide management but not for diagnosis ¹.
• Imaging is not routinely recommended in primary care unless red flags are present or symptoms persist/worsen, as imaging findings (e.g., disc herniation) may not correlate with symptoms and other causes of nerve root pain must be excluded ³.
• Exclude other causes of nerve root pain such as spinal stenosis, inflammatory diseases, or referred pain from other structures by thorough clinical assessment and history ³.

In summary, differentiation relies primarily on careful clinical evaluation to identify typical radicular features and neurological signs of herniated disc sciatica, while excluding red flags and other diagnoses. Imaging and specialist referral are reserved for cases with red flags or non-improving symptoms ¹,²,³.