What criteria should I use to determine whether to refer a patient with acute pain for specialist evaluation?

Criteria for referral of a patient with acute pain for specialist evaluation include:

• Presence of red flag symptoms such as sudden-onset headache reaching maximum intensity within 5 minutes, new neurological deficits, cognitive dysfunction, personality changes, impaired consciousness, recent head trauma, or headache triggered by cough, Valsalva, or exercise, which warrant urgent assessment and possible referral (CG150) NICE CG150.
• Signs suggestive of serious underlying conditions like giant cell arteritis (e.g., scalp tenderness, jaw claudication), acute narrow angle glaucoma, or suspected cancer require prompt referral and further investigations (NG127, CG150) NICE NG127,NICE CG150.
• For acute low back pain starting before age 45 and lasting more than 3 months, referral to rheumatology is indicated if 4 or more specific criteria are met, including improvement with movement, nocturnal pain, family history of spondyloarthritis, or associated arthritis or psoriasis (NG65) NICE NG65.
• Persistent or refractory unilateral facial pain triggered by touching the face (trigeminal neuralgia) should be referred for specialist assessment (NG127) NICE NG127.
• Rapidly progressive neurological symptoms such as rapidly progressive unsteady gait or sudden-onset difficulty with handwriting without musculoskeletal cause require urgent neurological referral (NG127) NICE NG127.
• Consider referral when acute pain is disproportionate to any observable injury or when the pain causes significant distress and disability, especially if chronic primary pain is suspected (NG193) NICE NG193.

In summary, referral decisions should be based on the presence of red flag symptoms, neurological signs, suspicion of inflammatory or serious systemic disease, refractory pain syndromes, and significant functional impact.