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As the most common cause of clinic visits due to nerve entrapment, carpal tunnel syndrome affects a significant portion of the population. Often, history and physical exam may be inadequate to evaluate the severity fully or to confirm the diagnosis. This activity describes the invaluable electrodiagnostic findings of nerve conduction tests and needle electromyography studies and highlights the role of the interprofessional team in evaluating patients with carpal tunnel syndrome. Objectives: Identify the indications for electrodiagnostic testing in patients suspected of carpal tunnel syndrome. Describe the nerve conduction study findings in a patient with carpal tunnel syndrome. Review the electromyographic findings in a patient with carpal tunnel syndrome. Outline the importance of communication among the interprofessional team to enhance the delivery of care for patients with carpal tunnel syndrome. Access free multiple choice questions on this topic.

Carpal tunnel syndrome (CTS) accounts for approximately 90% of all focal entrapment neuropathy, making it a frequent electrodiagnostic consultation. It is present in about 3.8% of the general population. It is more common in women than in men, and while it occurs in all age groups, incidence generally reaches a peak within the age of 40 to 60 years.[1] Hypothyroidism, diabetes mellitus, rheumatoid arthritis, gout, peripheral edema, acromegaly, tumors, trauma, and pregnancy are risk factors that predispose patients to develop CTS. Furthermore, patients whose occupations rely on the hands' repetitive movements and those with forceful hand movements are also prone to developing CTS.[2] The clinical presentation typically reveals numbness, weakness, and paresthesias within the thumb, index, middle, and radial side of the ring finger.[3] The thenar area has normal sensation as the palmar cutaneous sensory branch innervates it, which does not pass through the carpal tunnel. However, the recurrent thenar motor branch does pass through the carpal tunnel and gives innervation to the opponens pollicis, abductor pollicis brevis, and superficial head of the flexor pollicis brevis. Patients' symptoms tend to worsen at night or during the hand's repetitive movements, especially those requiring prolonged wrist flexion.[2] Depending on the severity of the patient's symptoms, they can categorize into three stages. Stage 1 presents with frequent awakenings at night due to tingling in their hands and fingers, which may last through the morning with associated stiffness. Stage 2 shows symptoms that are also present during the day. Motor deficits may also be apparent with patients reporting dropping objects from their hands. Stage 3, the final stage, demonstrates atrophy of the thenar muscles and may respond poorly to surgical decompression.[1]

As with all electrodiagnostic studies in any setting and for any indication, the risk of complications is low. There is always a small risk of bleeding or introducing infection with needle studies.[8] Mild procedural pain and discomfort also require explanation, especially when performing needle EMG on muscles such as the abductor pollicis brevis.[4][8]

CTS is a condition often seen in the outpatient setting. Patients frequently come with complaints of pain and paresthesias in the hands. Imaging studies, in addition to electrodiagnostic studies, can be routinely ordered. Physicians must be cautious, however, as imaging findings may not correlate with the patient's symptoms. Interprofessional care must use an evidence-based approach for evaluation and management. When CTS is left untreated, mild symptoms may subsequently lead to weakness and atrophy.[7] Treatment of CTS generally involves the use of conservative management such as wrist splints and non-steroidal anti-inflammatory drugs. Should these fail, other more invasive options may include local corticosteroid injections and surgery involving carpal tunnel release.[3][7] It is essential to take an interprofessional team including physiatrists, orthopedists, hand surgeons, neurosurgeons, physical/occupational therapists, and social workers who can work together to coordinate outpatient therapy, aggressive multifaceted rehabilitation, and ultimately, surgery to improve a patient's functional status.