A multifaceted presentation of acute neck pain with thumb weakness: A case report

Abstract

Background: Cervical radiculopathy often presents with neck and upper limb pain, sensory changes, and motor deficits, affecting 0.832 to 1.79 per 1,000 person-years. Concurrent musculoskeletal conditions, such as peripheral neuropathies and tendon injuries, can complicate diagnosis due to overlapping symptoms. This review highlights the diagnostic challenges through a case report of a 60-year-old female with left neck pain and upper limb symptoms indicative of cervical radicular arm pain and acute left thumb weakness.

Case presentation: The patient had a six-week history of left-sided neck, periscapular, and upper limb pain radiating to the thumb, with severe thumb weakness emerging 24 hours after onset. Examination revealed left cervical paraspinal tenderness, restricted neck motion, preserved upper limb sensation, symmetrical reflexes, but profound weakness in the abductor pollicis longus and extensor pollicis brevis. Magnetic Resonance Imaging (MRI) revealed disc bulges with osteophytes of endplates at C5-6 and C6-7, and C7-T1 with corresponding nerve root compression. Electromyography (EMG) indicated mild multilevel radiculopathy. Further investigation using ultrasound imaging identified a complete rupture of the abductor pollicis longus tendon and a possible extensor pollicis brevis tear. The diagnosis included multilevel cervical foraminal stenosis causing radiating upper limb pain and a spontaneous tendon rupture causing thumb weakness.

Conclusion: In this case, careful assessment of discrepancies between pain distribution and motor deficits, supported by imaging and electrodiagnostic studies, was essential to identify distal abductor pollicis longus tendon rupture and concurrent cervical degenerative changes, allowing appropriate management. This outcome highlights the importance of systematic reasoning tailored to this patient's presentation.

Keywords: Cervical radiculopathy; abductor pollicis longus tendon rupture; clinical reasoning; posterior interosseous nerve.