Nerve entrapment syndromes
Focal compressive or traction injuries of peripheral nerves cause sensory disturbance, pain and - if prolonged - motor dysfunction in a defined distribution. In emergency medicine the common presentations are:
- Median nerve at the wrist (carpal tunnel syndrome)
- Ulnar nerve at the elbow (cubital tunnel) or wrist (Guyon’s canal)
- Radial nerve in the proximal forearm (radial tunnel / posterior interosseous nerve)
Emergency department (ED) priorities are recognition, focused assessment for red flags or systemic causes, symptom relief, occupational history and timely referral in line with local pathways (NICE NG127).
Pathophysiology and general principles
- Compression or repetitive microtrauma causes ischaemia, impaired axonal transport and demyelination; prolonged compression produces axonal loss and muscle denervation.
- Symptoms are typically distal and focal: paresthesia, numbness, neuropathic pain and, later, weakness or wasting of innervated muscles.
- Double‑crush effect: proximal nerve lesions (for example, cervical radiculopathy) may predispose to distal entrapment.
- Systemic conditions (diabetes, hypothyroidism, B12 deficiency, renal disease, inflammatory arthropathy, pregnancy) increase risk - assess for reversible causes when presentation is not purely focal (NICE NG127).
Focused assessment in the ED
- History: distribution of symptoms, onset, nocturnal pattern, aggravating and relieving factors, trauma, occupation (repetitive hand use, vibration, cycling handlebars), systemic symptoms and relevant comorbidities.