Upper extremity mononeuropathy refers to pathology affecting a single peripheral nerve of the upper limb. The peripheral nerve may be damaged anywhere along its course from the spinal nerve root, as part of the brachial plexus, or along its terminal branches. Damage results in weakness, disturbance of sensation, and/or pain. Generally, the term mononeuropathy refers to nerve damage occurring distal to the brachial plexus. There are more than 10 individual nerves in the arm distal to the brachial plexus, so many different mononeuropathies can occur. Occasionally more than one individual nerve is affected. This may be referred to as mononeuropathy multiplex, although this term virtually always connotes a vasculitic process affecting multiple peripheral nerves.
Summary
Compression neuropathies
The most common mononeuropathies of the upper extremity are carpal tunnel syndrome, ulnar neuropathy, and radial neuropathy.[1] These are believed to be due to mechanical injury caused by compression or trauma. Most commonly this can be seen in the median nerve at the wrist (carpal tunnel syndrome) or in the ulnar nerve at the elbow.[1] [2] Trauma is the most frequent cause of the less common radial neuropathy, although this can also occur from compression over the spiral groove (Saturday night palsy).[3] These relatively benign mononeuropathies must be differentiated from more sinister causes, which tend to occur outside of compression sites and frequently involve more than one nerve (i.e., mononeuritis multiplex). Lesions in the spinal nerve root and in the brachial plexus also have different etiologic considerations and need to be differentiated from the more common compression/traumatic neuropathies.
Inflammation, malignancy, and infection
The occurrence of multiple mononeuropathies outside of compression sites suggests vasculitis or segmental demyelination in the context of antibodies against some of the peripheral myelin compounds. Although both are rare, recognizing these conditions (particularly vasculitis) is critical. Brachial plexopathies are often idiopathic. Idiopathic brachial plexopathy has many synonyms, including brachial neuritis, Parsonage-Turner syndrome, and brachial amyotrophy. However, unlike in the distal nerve where tumors are rare, extrinsic compression by malignancy needs to be considered, particularly when symptoms localize to the medial cord or lower trunk of the brachial plexus, a localization that can appear to mimic an ulnar neuropathy. Nerve root lesions can also mimic the distal mononeuropathies. In general, these result from traumatic or degenerative disk disease. However, malignancy and infection can also cause cervical radiculopathies and need to be considered in the appropriate setting.
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Severe bilateral carpal tunnel syndrome resulting in atrophy of abductor pollicis brevis
Approximate distribution of ulnar sensory nerve on dorsum of hand
Approximate distribution of ulnar sensory nerve on palm
Severe ulnar neuropathy; note atrophy of first dorsal interosseus and inability to extend proximal interphalangeal (PIP) joints of fourth and fifth digits
Approximate distribution of radial sensory nerve
Marked atrophy of both the thenar eminence and the first dorsal interosseus is seen in thoracic outlet syndrome; it should be noted that this is an extremely rare diagnosis
Approximate distribution of median sensory nerve on palm
Testing thumb abduction strength in assessment of carpal tunnel syndrome: with palm facing up, patient lifts thumb toward ceiling, and resistance is applied as shown
Citations
Doughty CT, Bowley MP. Entrapment neuropathies of the upper extremity. Med Clin North Am. 2019 Mar;103(2):357-70.[Abstract]
Padua L, Cuccagna C, Giovannini S, et al. Carpal tunnel syndrome: updated evidence and new questions. Lancet Neurol. 2023 Mar;22(3):255-67.[Abstract]
Graham B, Peljovich AE, Afra R, et al. The American Academy of Orthopaedic Surgeons evidence-based clinical practice guideline on: management of carpal tunnel syndrome. J Bone Joint Surg Am. 2016 Oct 19;98(20):1750-4.[Abstract][Full Text]
1. Latinovic R, Gulliford MC, Hughes RA. Incidence of common compressive neuropathies in primary care. J Neurol Neurosurg Psychiatry. 2006;77(2):263-5.[Abstract][Full Text]
2. Doughty CT, Bowley MP. Entrapment neuropathies of the upper extremity. Med Clin North Am. 2019 Mar;103(2):357-70.[Abstract]
3. Węgiel A, Karauda P, Zielinska N, et al. Radial nerve compression: anatomical perspective and clinical consequences. Neurosurg Rev. 2023 Feb 13;46(1):53.[Abstract][Full Text]
4. Padua L, Cuccagna C, Giovannini S, et al. Carpal tunnel syndrome: updated evidence and new questions. Lancet Neurol. 2023 Mar;22(3):255-67.[Abstract]
5. Australian Government Department of Health and Aged Care. Pregnancy care guidelines: carpal tunnel syndrome. May 2019 [internet publication].[Full Text]
6. Joshi A, Patel K, Mohamed A, et al. Carpal tunnel syndrome: pathophysiology and comprehensive guidelines for clinical evaluation and treatment. Cureus. 2022 Jul;14(7):e27053.[Abstract][Full Text]
7. Jackson R, Beckman J, Frederick M, et al. Rates of carpal tunnel syndrome in a state workers' compensation information system, by industry and occupation, California, 2007-2014. MMWR Morb Mortal Wkly Rep. 2018 Oct 5;67(39):1094-7.[Abstract][Full Text]
8. Slobogean BL, Jackman H, Tennant S, et al. Iatrogenic ulnar nerve injury after the surgical treatment of displaced supracondylar fractures of the humerus: number needed to harm, a systematic review. J Pediatr Orthop. 2010 Jul-Aug;30(5):430-6.[Abstract]
9. Ebenezer GJ, Scollard DM. Treatment and evaluation advances in leprosy neuropathy. Neurotherapeutics. 2021 Oct;18(4):2337-50.[Abstract][Full Text]
10. Brubacher JW, Leversedge FJ. Ulnar neuropathy in cyclists. Hand Clin. 2017 Feb;33(1):199-205.[Abstract]
11. Jones MR, Prabhakar A, Viswanath O, et al. Thoracic outlet syndrome: a comprehensive review of pathophysiology, diagnosis, and treatment. Pain Ther. 2019 Jun;8(1):5-18.[Abstract][Full Text]
12. Aljawder A, Faqi MK, Mohamed A, et al. Anterior interosseous nerve syndrome diagnosis and intraoperative findings: a case report. Int J Surg Case Rep. 2016;21:44-7.[Abstract][Full Text]
13. Feinberg JH, Radecki J. Parsonage-turner syndrome. HSS J. 2010 Sep;6(2):199-205.[Abstract][Full Text]
14. Masrori P, Van Damme P. Amyotrophic lateral sclerosis: a clinical review. Eur J Neurol. 2020 Oct;27(10):1918-29.[Abstract][Full Text]
15. Zaki HA, Shaban E, Salem W, et al. A comparative analysis between ultrasound and electromyographic and nerve conduction studies in diagnosing carpal tunnel syndrome (CTS): a systematic review and meta-analysis. Cureus. 2022 Oct;14(10):e30476.[Abstract][Full Text]
16. Graham B, Peljovich AE, Afra R, et al. The American Academy of Orthopaedic Surgeons evidence-based clinical practice guideline on: management of carpal tunnel syndrome. J Bone Joint Surg Am. 2016 Oct 19;98(20):1750-4.[Abstract][Full Text]
17. Wilbourn AJ, Aminoff MJ. AAEM minimonograph 32: the electrodiagnostic examination in patients with radiculopathies. Muscle Nerve. 1998 Dec;21(12):1612-31.[Abstract]
18. Levin KH, Maggiano HJ, Wilbourn AJ. Cervical radiculopathies: comparison of surgical and EMG localization of single-root lesions. Neurology. 1996 Apr;46(4):1022-5.[Abstract]
19. Modic MT, Obuchowski NA, Ross JS, et al. Acute low back pain and radiculopathy: MR imaging findings and their prognostic role and effect on outcome. Radiology. 2005;237:597-604.[Abstract]
20. Rubin DI. Brachial and lumbosacral plexopathies: a review. Clin Neurophysiol Pract. 2020;5:173-93.[Abstract][Full Text]
21. Wittenberg KH, Adkins MC. MR imaging of nontraumatic brachial plexopathies: frequency and spectrum of findings. Radiographics. 2000 Jul-Aug;20(4):1023-32.[Abstract]
22. Kichari JR, Hussain SM, Den Hollander JC, et al. MR imaging of the brachial plexus: current imaging sequences, normal findings, and findings in a spectrum of focal lesions with MR-pathologic correlation. Curr Probl Diagn Radiol. 2003 Mar;32(2):88-101.[Abstract]
23. Fathers E, Thrush D, Huson SM, et al. Radiation-induced brachial plexopathy in women treated for carcinoma of the breast. Clin Rehabil. 2002 Mar;16(2):160-5.[Abstract]
24. Stubblefield MD. Neuromuscular complications of radiation therapy. Muscle Nerve. 2017 Dec;56(6):1031-40.[Abstract]
25. Gwathmey KG, Burns TM, Collins MP, et al. Vasculitic neuropathies. Lancet Neurol. 2014 Jan;13(1):67-82.[Abstract]
26. Van den Bergh PYK, van Doorn PA, Hadden RDM, et al. European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of chronic inflammatory demyelinating polyradiculoneuropathy: report of a joint task force-second revision. J Peripher Nerv Syst. 2021 Sep;26(3):242-68.[Abstract][Full Text]
27. Garcia-Monco JC, Benach JL. Lyme neuroborreliosis: clinical outcomes, controversy, pathogenesis, and polymicrobial infections. Ann Neurol. 2019 Jan;85(1):21-31.[Abstract][Full Text]
28. Halperin J, Luft BJ, Volkman DJ, et al. Lyme neuroborreliosis. Peripheral nervous system manifestations. Brain. 1990 Aug;113(Pt 4):1207-21.[Abstract]
29. National Institute for Health and Care Excellence. Lyme disease. Oct 2018 [internet publication].[Full Text]
30. Mead P, Petersen J, Hinckley A. Updated CDC recommendation for serologic diagnosis of Lyme disease. MMWR Morb Mortal Wkly Rep 2019;68:703.[Abstract][Full Text]
