Radiculopathy
Radiculopathy
A radiculopathy is a disorder of nerve roots, causing pain in a radicular distribution, paresthesia, sensory diminution or loss in the corresponding dermatome, and lower motor neurone type weakness with reflex diminution or loss in the corresponding myotome. Radiculopathies may be single or multiple (polyradiculopathy, e.g., cauda equina syndrome). There may be concurrent myelopathy, typically of extrinsic or extramedullary type.
Most radiculopathies are in the lumbosacral region (60-90%), followed by the cervical region (5-30%).
Electrophysiological studies may be helpful in distinguishing radiculopathy from a neuropathy or plexopathy: sensory nerve action potentials (SNAPs) are normal for intrathecal root lesions, and EMG shows involvement of paraspinal muscles.
- Recognized causes of radiculopathy include: Structural lesions:
Compression: disc protrusion: cervical (especially C6, C7), lumbar (L5, S1) >>> thoracic; bony metastases; spondylolisthesis; fracture; infection.
Root avulsion, e.g., C5/C6, "waiter’s tip" posture; C8/T1, claw hand +/− Horner’s syndrome.
Diabetic polyradiculopathy: thoraco-abdominal, lumbosacral (= diabetic amyotrophy, also known as diabetic lumbar sacral plexopathy, proximal diabetic neuropathy; especially involves L2-L4).
Neoplasia: with meningeal symptoms, due to spread from carcinoma of breast or lung, melanoma, nonHodgkin’s lymphoma, leukemia.
Infection: HIV (CMV late in the course), Borrelia (Lyme disease), syphilis (tabes dorsalis), herpes zoster (thoracic > cervical > lumbosacral; sensory >> motor), leprosy. Demyelination: Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculopathy (CIDP).
References
Chad DF. Nerve root and plexus disorders. In: Bogousslavsky J, Fisher M (Eds.). Textbook of neurology. Boston: ButterworthHeinemann, 1998: 491-506
Feldman EL, Grisold W, Russell JW, Zifko U. Atlas of neuromuscular disease. A practical guideline. Vienna: Springer, 2005: 117-139
Cross References
Cauda equina syndrome; Lasègue’s sign; Myelopathy; Neuropathy; Paresthesia; Plexopathy; Reflexes; "Waiter’s tip" posture; Weakness
