Close
New

Medscape is available in 5 Language Editions – Choose your Edition here.

 

Carpal Tunnel Syndrome Workup

  • Author: Nigel L Ashworth, MBChB, MSc, FRCPC; Chief Editor: Robert H Meier, III, MD  more...
 
Updated: Jul 01, 2015
 

Laboratory Studies

No blood tests exist for the diagnosis of carpal tunnel syndrome; however, laboratory testing for associated conditions (eg, diabetes) may be performed when clinically indicated.

Next

Imaging Studies

No imaging studies are considered routine in the diagnosis of carpal tunnel syndrome (CTS).

Magnetic resonance imaging (MRI) of the carpal tunnel is particularly useful preoperatively if a space-occupying lesion in the carpal tunnel is suggested. Signal abnormality can be detected in the median nerve in some cases of CTS, but how these abnormalities correlate to diagnosis and physiologic severity is not clear. MRI does not rule out the multitude of other differential diagnoses and is time consuming and resource intensive.[11]

Many clinical neurophysiology laboratories are now using ultrasonography as an adjunct to electrodiagnostic studies. Ultrasound potentially can identify space-occupying lesions in and around the median nerve, confirm abnormalities in the median nerve (eg increased cross sectional area) that can be diagnostic of CTS, and help guide steroid injections into the carpal tunnel.[12, 13, 14]

Previous
Next

Other Tests

Electrophysiologic studies,[15, 16, 17] including electromyography (EMG) and nerve conductions studies (NCS), are the first-line investigations in suggested carpal tunnel syndrome (CTS).[18] Abnormalities on electrophysiologic testing, in association with specific symptoms and signs, are considered the criterion standard for CTS diagnosis. In addition, other neurologic diagnoses can be excluded with these test results. NCS in a patient with CTS are seen in the images below.

Sensory nerve conduction studies from the left han Sensory nerve conduction studies from the left hand of a patient with a several-year history of numbness and weakness (responses from the median nerve in the right hand were completely absent). Note marked slowing of the conduction velocity (CV) to 29.8 and 25.5 m/s for digits 3 and 1, respectively (normal >50 m/s). The amplitude for both also is reduced markedly (normal >10). These findings are consistent with carpal tunnel syndrome.
Motor nerve conduction studies from the left hand Motor nerve conduction studies from the left hand of a patient with a several-year history of numbness and weakness (responses from the median nerve in the right hand were completely absent). Note that the conduction velocity (CV) across the carpal tunnel segment slows severely to 18.3 m/s (normal >50 m/s) and that the distal motor latency is prolonged at 6.3 ms (normal < 4.2 ms). Amplitudes are low for the wrist and elbow stimulus sites at 4.7 mV (normal >5 mV), but amplitudes are 31% higher distal to the carpal tunnel (at the palm). This discrepancy may represent conduction block (neurapraxia) at the level of the carpal tunnel or coactivation of the ulnar branch to adductor pollicis. Needle electromyography is required to determine whether axonal loss is present.

Electrophysiologic testing also can provide an accurate assessment of how severe the damage to the nerve is, thereby directing management and providing objective criteria for the determination of prognosis. CTS is usually divided into mild, moderate, and severe; however, criteria for this assessment usually vary from lab to lab. In general, patients with mild CTS have sensory abnormalities alone on electrophysiologic testing, and patients with sensory plus motor abnormalities have moderate CTS. However, any evidence of axonal loss (eg, decreased or absent sensory or motor responses distal to the carpal tunnel or neuropathic abnormalities on needle EMG) is classified as severe CTS.

Changes in electrophysiologic results over time can be used to assess the success of various treatment modalities.

The American Association of Electrodiagnostic Medicine has published standards and guidelines that govern the minimum number of studies that should be performed to diagnose CTS.[16]

Other quantitative tests, such as thermography and vibrometry, have been shown to be inferior to electrophysiologic examination and, because they have not been supported by controlled studies, are not recommended.

Previous
 
 
Contributor Information and Disclosures
Author

Nigel L Ashworth, MBChB, MSc, FRCPC Professor, Divisions of Physical Medicine and Rehabilitation and Neurology, University of Alberta Faculty of Medicine and Dentistry, Canada

Nigel L Ashworth, MBChB, MSc, FRCPC is a member of the following medical societies: Canadian Society of Clinical Neurophysiologists, Australian & New Zealand Association of Neurologists, American Association of Neuromuscular and Electrodiagnostic Medicine, British Medical Association, Canadian Medical Association, Royal College of Physicians and Surgeons of Canada

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Patrick M Foye, MD Director of Coccyx Pain Center, Professor and Interim Chair of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School; Co-Director of Musculoskeletal Fellowship, Co-Director of Back Pain Clinic, University Hospital

Patrick M Foye, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, International Spine Intervention Society, American Association of Neuromuscular and Electrodiagnostic Medicine, Association of Academic Physiatrists

Disclosure: Nothing to disclose.

Chief Editor

Robert H Meier, III, MD Director, Amputee Services of America; Active Medical Staff, Presbyterian/St Luke’s Hospital, Spalding Rehabilitation Hospital, Select Specialty Hospital; Consulting Staff, Kindred Hospital

Robert H Meier, III, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, Association of Academic Physiatrists

Disclosure: Nothing to disclose.

Additional Contributors

Benjamin M Sucher, DO, FAOCPMR, FAAPMR Medical Director, EMG Labs of AARA (Arizona Arthritis and Rheumatology Associates)

Benjamin M Sucher, DO, FAOCPMR, FAAPMR is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Osteopathic College of Physical Medicine and Rehabilitation, Arizona Society of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Osteopathic Association

Disclosure: Nothing to disclose.

References
  1. de Krom MC, Kester AD, Knipschild PG, et al. Risk factors for carpal tunnel syndrome. Am J Epidemiol. 1990 Dec. 132(6):1102-10. [Medline].

  2. Atroshi I, Gummesson C, Johnsson R, et al. Prevalence of carpal tunnel syndrome in a general population. JAMA. 1999 Jul 14. 282(2):153-8. [Medline]. [Full Text].

  3. de Krom MC, Knipschild PG, Kester AD, et al. Carpal tunnel syndrome: prevalence in the general population. J Clin Epidemiol. 1992 Apr. 45(4):373-6. [Medline].

  4. Goga IE. Carpal tunnel syndrome in black South Africans. J Hand Surg [Br]. 1990 Feb. 15(1):96-9. [Medline].

  5. Garland FC, Garland CF, Doyle EJ Jr, et al. Carpal tunnel syndrome and occupation in U.S. Navy enlisted personnel. Arch Environ Health. 1996 Sep-Oct. 51(5):395-407. [Medline].

  6. Durkan JA. The carpal-compression test. An instrumented device for diagnosing carpal tunnel syndrome. Orthop Rev. 1994 Jun. 23(6):522-5. [Medline].

  7. Kao SY. Carpal tunnel syndrome as an occupational disease. J Am Board Fam Pract. 2003 Nov-Dec. 16(6):533-42. [Medline]. [Full Text].

  8. Palmer KT, Harris EC, Coggon D. Carpal tunnel syndrome and its relation to occupation: a systematic literature review. Occup Med (Lond). 2007 Jan. 57(1):57-66. [Medline].

  9. Bernard PB, ed. Musculoskeletal Disorders and Workplace Factors: A Critical Review of Epidemiologic Evidence for Work-Related Musculoskeletal Disorders of the Neck, Upper Extremity, and Low Back. National Institute for Occupational Safety and Health. Jul 1997. Available at http://www.cdc.gov/niosh/docs/97-141/.

  10. Fernandez-Munoz JJ, Palacios-Cena M, Cigaran-Mendez M, et al. Pain is Associated to Clinical, Psychological, Physical, and Neuro-physiological Variables in Women with Carpal Tunnel Syndrome. Clin J Pain. 2015 Apr 15. [Medline].

  11. Zagnoli F, Andre V, Le Dreff P, et al. Idiopathic carpal tunnel syndrome. Clinical, electrodiagnostic, and magnetic resonance imaging correlations. Rev Rhum Engl Ed. 1999 Apr. 66(4):192-200. [Medline].

  12. Lee D, van Holsbeeck MT, Janevski PK, et al. Diagnosis of carpal tunnel syndrome. Ultrasound versus electromyography. Radiol Clin North Am. 1999 Jul. 37(4):859-72, x. [Medline].

  13. Tai TW, Wu CY, Su FC, Chern TC, Jou IM. Ultrasonography for diagnosing carpal tunnel syndrome: a meta-analysis of diagnostic test accuracy. Ultrasound Med Biol. 2012 Jul. 38(7):1121-8. [Medline].

  14. Cartwright MS. Ultrasound of focal neuropathies. Walker FO, Cartwright MS, eds. Neuromuscular Ultrasound. Philadelphia, Pa: Elsevier Saunders; 2011. 74-76.

  15. Robinson LR. Electrodiagnosis of carpal tunnel syndrome. Phys Med Rehabil Clin N Am. 2007 Nov. 18(4):733-46, vi. [Medline].

  16. Practice parameter for electrodiagnostic studies in carpal tunnel syndrome: summary statement. American Association of Electrodiagnostic Medicine, American Academy of Neurology, American Academy of Physical Medicine and Rehabilitation. Muscle Nerve. 1993 Dec. 16(12):1390-1. [Medline].

  17. Stevens JC. AAEM minimonograph #26: the electrodiagnosis of carpal tunnel syndrome. American Association of Electrodiagnostic Medicine. Muscle Nerve. 1997 Dec. 20(12):1477-86. [Medline].

  18. Chang MH, Lee YC, Hsieh PF. The real role of forearm mixed nerve conduction velocity in the assessment of proximal forearm conduction slowing in carpal tunnel syndrome. J Clin Neurophysiol. 2008 Nov 6. [Medline].

  19. Banta CA. A prospective, nonrandomized study of iontophoresis, wrist splinting, and antiinflammatory medication in the treatment of early-mild carpal tunnel syndrome. J Occup Med. 1994 Feb. 36(2):166-8. [Medline].

  20. Page MJ, O'Connor D, Pitt V, Massy-Westropp N. Therapeutic ultrasound for carpal tunnel syndrome. Cochrane Database Syst Rev. 2012 Jan 18. 1:CD009601. [Medline].

  21. O'Connor D, Marshall S, Massy-Westropp N. Non-surgical treatment (other than steroid injection) for carpal tunnel syndrome. Cochrane Database Syst Rev. 2003. CD003219. [Medline].

  22. Incebiyik S, Boyaci A, Tutoglu A. Short-term effectiveness of short-wave diathermy treatment on pain, clinical symptoms, and hand function in patients with mild or moderate idiopathic carpal tunnel syndrome. J Back Musculoskelet Rehabil. 2014 Jul 24. [Medline].

  23. Page MJ, O'Connor D, Pitt V, Massy-Westropp N. Exercise and mobilisation interventions for carpal tunnel syndrome. Cochrane Database Syst Rev. 2012 Jun 13. 6:CD009899. [Medline].

  24. Page MJ, Massy-Westropp N, O'Connor D, Pitt V. Splinting for carpal tunnel syndrome. Cochrane Database Syst Rev. 2012 Jul 11. 7:CD010003. [Medline].

  25. O'Connor D, Page MJ, Marshall SC, Massy-Westropp N. Ergonomic positioning or equipment for treating carpal tunnel syndrome. Cochrane Database Syst Rev. 2012 Jan 18. 1:CD009600. [Medline].

  26. Ugurlu U, Ozkan M, Ozdogan H. The development of a new orthosis (neuro-orthosis) for patients with carpal tunnel syndrome: its effect on the function and strength of the hand. Prosthet Orthot Int. 2008 Dec. 32(4):403-21. [Medline].

  27. Marshall S, Tardif G, Ashworth N. Local corticosteroid injection for carpal tunnel syndrome. Cochrane Database Syst Rev. 2007. (2):CD001554. [Medline].

  28. Goodyear-Smith F, Arroll B. What can family physicians offer patients with carpal tunnel syndrome other than surgery? A systematic review of nonsurgical management. Ann Fam Med. 2004 May-Jun. 2(3):267-73. [Medline]. [Full Text].

  29. Meys V, Thissen S, Rozeman S, Beekman R. Prognostic factors in carpal tunnel syndrome treated with a corticosteroid injection. Muscle Nerve. 2011 Nov. 44(5):763-8. [Medline].

  30. Scholten RJ, Mink van der Molen A, Uitdehaag BM, et al. Surgical treatment options for carpal tunnel syndrome. Cochrane Database Syst Rev. 2007. (4):CD003905. [Medline].

  31. Boya H, Ozcan O, Oztekin HH. Long-term complications of open carpal tunnel release. Muscle Nerve. 2008 Nov. 38(5):1443-6. [Medline].

  32. Verdugo RJ, Salinas RA, Castillo JL, Cea JG. Surgical versus non-surgical treatment for carpal tunnel syndrome. Cochrane Database Syst Rev. 2008 Oct 8. CD001552. [Medline].

  33. Rozanski M, Neuhaus V, Thornton E, Becker SJ, Rathmell JP, Ring D. Symptoms During or Shortly After Isolated Carpal Tunnel Release and Problems Within 24 hours After Surgery. J Hand Microsurg. 2015 Jun. 7 (1):30-5. [Medline].

  34. Verhagen AP, Karels C, Bierma-Zeinstra SM, et al. Ergonomic and physiotherapeutic interventions for treating work-related complaints of the arm, neck or shoulder in adults. A Cochrane systematic review. Eura Medicophys. 2007 Sep. 43(3):391-405. [Medline].

 
Previous
Next
 
The hands of an 80-year-old woman with a several-year history of numbness and weakness are shown in this photo. Note severe thenar muscle (abductor pollicis brevis, opponens pollicis) wasting of the right hand, with preservation of hypothenar eminence.
Sensory nerve conduction studies from the left hand of a patient with a several-year history of numbness and weakness (responses from the median nerve in the right hand were completely absent). Note marked slowing of the conduction velocity (CV) to 29.8 and 25.5 m/s for digits 3 and 1, respectively (normal >50 m/s). The amplitude for both also is reduced markedly (normal >10). These findings are consistent with carpal tunnel syndrome.
Motor nerve conduction studies from the left hand of a patient with a several-year history of numbness and weakness (responses from the median nerve in the right hand were completely absent). Note that the conduction velocity (CV) across the carpal tunnel segment slows severely to 18.3 m/s (normal >50 m/s) and that the distal motor latency is prolonged at 6.3 ms (normal < 4.2 ms). Amplitudes are low for the wrist and elbow stimulus sites at 4.7 mV (normal >5 mV), but amplitudes are 31% higher distal to the carpal tunnel (at the palm). This discrepancy may represent conduction block (neurapraxia) at the level of the carpal tunnel or coactivation of the ulnar branch to adductor pollicis. Needle electromyography is required to determine whether axonal loss is present.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.