Carpal Tunnel Syndrome: Diagnosis and Management JENNIFER WIPPERMAN, MD, MPH, and KYLE GOERL, MD, Via Christi Family Medicine Residency, University of Kansas School of Medicine–Wichita, Wichita, Kansas Carpal tunnel syndrome, the most common entrapment neuropathy of the upper extremity, is caused by compression of the median nerve as it travels through the carpal tunnel. Classically, patients with the condition experience pain and paresthesias in the distribution of the median nerve, which includes the palmar aspect of the thumb, index and middle fingers, and radial half of the ring finger. Additional clues include positive physical examination findings, such as the flick sign, Phalen maneuver, and median nerve compression test. Although patients with typical symptoms and signs of carpal tunnel syndrome do not need additional testing, ultrasonography and electrodiagnostic studies are useful to confirm the diagnosis in atypical cases and rule out other causes. If surgical decompression is planned, electrodiagnostic studies should be obtained to determine severity and surgical prognosis. Conservative treatment may be offered initially to patients with mild to moderate carpal tunnel syndrome. Options include splinting, cor- ticosteroids, physical therapy, therapeutic ultrasound, and yoga. Nonsteroidal anti-inflammatory drugs, diuretics, and vitamin B6 are not effective therapies. Local corticosteroid injection can provide relief for more than one month and delay the need for surgery at one year. Patients with severe carpal tunnel syndrome or whose symptoms have not improved after four to six months of conservative therapy should be offered surgical decompression. Endoscopic and open techniques are equally effective, but patients return to work an average of one week earlier with endoscopic repair. (Am Fam Physician. 2016;94(12):993-999. Copyright © 2016 American Academy of Family Physicians.) CME This clinical content arpal tunnel syndrome (CTS) is Symptoms conforms to AAFP criteria often a debilitating disorder that The hallmarks of CTS are pain and paresthe- for continuing medical education (CME). See is commonly encountered in pri- sias in the distribution of the median nerve, CME Quiz Questions on mary care. It is the most common which includes the palmar aspect of the page 968. Centrapment neuropathy of the upper extrem- thumb, index and middle fingers, and radial 5 Author disclosure: No rel- ity, affecting approximately 3% of the general half of the ring finger (Figure 1 ). Symptoms evant financial affiliations. adult population.1 Women are three times can vary widely and occasionally localize to ▲ Patient information: more likely to have CTS than men, and the the wrist or the entire hand, or radiate to A handout on this topic is prevalence and severity increase with age. the forearm or rarely the shoulder. Patients available at http://www. Work-related activities that require a high often awaken with symptoms and shake out aafp.org/afp/2016/1215/ degree of repetition and force or use of hand- their hand to provide relief. This is known as p993-s1.html. operated vibratory tools significantly increase the flick sign, and is 93% sensitive and 96% the risk of CTS.2 A large prospective cohort specific for CTS.6 Other provoking factors study found that forceful hand exertion was include tasks that require repetitive wrist the most important factor in the development flexion or hand elevation, such as driving or of CTS in workers.3 Additional risk factors holding a telephone for extended periods. include family history and a personal history Because sensory fibers are more suscep- of diabetes mellitus, obesity, hypothyroidism, tible to compression than motor fibers, par- pregnancy, and rheumatoid arthritis. esthesias and pain usually predominate early The carpal tunnel is bordered superiorly in the course of CTS. In more severe cases, by the transverse carpal ligament and inferi- motor fibers are affected, leading to weak- orly by the carpal bones, through which the ness of thumb abduction and opposition. median nerve and nine flexor tendons of the Patients may describe difficulty holding forearm pass. Increased pressure in the car- objects, opening jars, or buttoning a shirt. pal tunnel leads to compression and damage Disappearance of pain is a late finding that of the median nerve.4 implies permanent sensory loss. DecemberDownloaded 15, from 2016 the American◆ Volume Family 94, Number Physician 12website at www.aafp.org/afp.www.aafp.org/afp Copyright © 2016 American Academy of FamilyAmerican Physicians. Family For the Physician private, noncom 993- mercial use of one individual user of the website. All other rights reserved. Contact [email protected] for copyright questions and/or permission requests. Carpal Tunnel Syndrome SORT: KEY RECOMMENDATIONS FOR PRACTICE Evidence Clinical recommendation rating References Ultrasound measurement of a cross-sectional area C 14, 15 In more severe disease, permanent sensory of the median nerve by an experienced clinician and motor deficits occur. Patients may have may be used as a diagnostic test for carpal tunnel syndrome. decreased sensation to pain (hypalgesia) on Local corticosteroid injection is effective for more A 20-24 the palmar aspect of the index finger com- than one month in patients with mild to moderate pared with the ipsilateral little finger on the carpal tunnel syndrome and delays the need for affected hand. Lack of two-point discrimina- surgery at one year. tion manifests as the inability to distinguish Splinting, therapeutic ultrasound, carpal bone B 25-27 8,9 mobilization, and nerve glide exercises are effective between points less than 6 mm apart. Sen- short-term treatments for carpal tunnel syndrome. sation over the thenar eminence should be Endoscopic and open carpal tunnel release are A 30 normal in patients with CTS because it is sup- equally effective, long-lasting treatments for plied by the palmar cutaneous branch of the carpal tunnel syndrome. median nerve, which branches off proximal to the carpal tunnel. Therefore, decreased A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited- quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual sensation over the thenar eminence indicates practice, expert opinion, or case series. For information about the SORT evidence a median nerve lesion proximal to the carpal rating system, go to http://www.aafp.org/afpsort. tunnel. Weakness of thumb abduction and opposition and atrophy of the thenar emi- nence may occur in advanced CTS. The diagnostic accuracy of provoca- tive maneuvers for CTS varies widely (Table 2).5,6,8,9 However, these tests are simple to perform, and a combination of positive findings increases the likelihood of CTS.9 The hand elevation test has similar sensitivity and specificity as the Phalen maneuver and the Tinel sign.10 To perform the hand eleva- tion test, the patient raises his or her hands above the head for one minute; the onset of symptoms is a positive result. One systematic review found that a classic or probable pat- tern on a hand symptom diagram (Figure 2 11) has a higher diagnostic accuracy than any single maneuver.8 Figure 1. Median nerve palmar distribution. Adjunctive Tests Reprinted with permission from LeBlanc KE, Cestia W. Carpal tunnel syndrome. Am Fam Physician. 2011;83(8):953. The diagnosis of CTS is clinical in a patient with characteristic symptoms and physical Physical Examination examination findings. However, electrodi- A complete examination of the entire upper agnostic studies aid in confirming the diag- extremity, including neck, shoulder, elbow, nosis in atypical cases, determining severity, and wrist, should be conducted to exclude and planning for surgery. Evidence suggests other causes (Table 15). Most patients with that ultrasonography may also be useful in early, mild to moderate CTS will not have diagnosing CTS. physical examination findings. However, initial inspection of the hand and wrist can ELECTRODIAGNOSTIC STUDIES provide clues to precipitating factors, such Electrodiagnostic studies include nerve as signs of injury or arthritic changes. A conduction studies and electromyography. square-shaped wrist (increased depth-to- Nerve conduction studies confirm CTS by width ratio) has an odds ratio of 4.56 (95% detecting impaired median nerve conduc- confidence interval, 2.97 to 6.99) for CTS, tion across the carpal tunnel, with normal likely related to obesity.7 conduction elsewhere. Electromyography 994 American Family Physician www.aafp.org/afp Volume 94, Number 12 ◆ December 15, 2016 Carpal Tunnel Syndrome Table 1. Differential Diagnosis of Carpal Tunnel Syndrome Condition Characteristics assesses pathologic changes in the muscles Carpometacarpal arthritis Painful thumb motion, positive grind test, of the thumb radiographic findings innervated by the median nerve, typically Cervical radiculopathy (C6) Neck pain, numbness of the thumb and index the abductor pollicis brevis muscle. finger only, positive Spurling test Electrodiagnostic studies can exclude other de Quervain tendinopathy Tenderness at the distal radial styloid conditions, such as polyneuropathy and Peripheral neuropathy History of diabetes mellitus; bilateral, lower radiculopathy, and gauge the severity of CTS. extremity involvement Electrodiagnostic studies have a sensitivity of Pronator syndrome (median Forearm pain; sensory loss over the thenar 56% to 85% and specificity of 94% to 99% for nerve compression at the eminence; weakness with thumb