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Carpal tunnel syndrome: Clinical manifestations and diagnosis

Carpal tunnel syndrome: Clinical manifestations and diagnosis
Literature review current through: Jan 2024.
This topic last updated: Oct 13, 2023.

INTRODUCTION — Carpal tunnel syndrome (CTS) refers to the complex of symptoms and signs brought on by compression of the median nerve as it travels through the carpal tunnel. Patients commonly experience pain and paresthesia, and less commonly weakness, in the median nerve distribution. CTS is the most frequent compressive focal mononeuropathy seen in clinical practice.

This topic will review the clinical manifestations and diagnosis of CTS. Other aspects of CTS are discussed separately.

(See "Carpal tunnel syndrome: Pathophysiology and risk factors".)

(See "Carpal tunnel syndrome: Treatment and prognosis".)

(See "Surgery for carpal tunnel syndrome".)

Other disorders involving nerves of the upper extremity are discussed separately. (See "Overview of upper extremity peripheral nerve syndromes".)

EPIDEMIOLOGY — CTS is a common disorder. The estimated prevalence of CTS in the general population is between 1 and 5 percent. CTS is more frequent in females, with a female-to-male ratio of approximately 3 to 1. The epidemiology of CTS is discussed in additional detail separately. (See "Carpal tunnel syndrome: Pathophysiology and risk factors", section on 'Epidemiology'.)

CLINICAL FEATURES — The hallmark of classic CTS is pain or paresthesia (numbness and tingling) in a distribution that includes the median nerve territory, with involvement of the first three digits and the lateral half of the fourth digit (figure 1).

Signs and symptoms – Although the sensory symptoms of CTS are usually limited to the median-innervated fingers, there can be significant variability. The pain and paresthesia may be localized to the wrist or it may involve the entire hand. It is not uncommon for sensory symptoms to radiate proximally into the forearm and, less frequently, to radiate above the elbow to the shoulder, but the neck is not affected [1].

In more severe cases of CTS, motor involvement leads to complaints of weakness or clumsiness when using the hands, such as difficulty holding objects, turning keys or doorknobs, buttoning clothing, or opening jar lids [1]. Clinical signs may include weakness of thumb abduction and opposition and atrophy of the thenar eminence.

Bilateral CTS is common, reported as affecting up to 65 percent of patients [2], though clinical experience suggests that a unilateral initial presentation of CTS is encountered more frequently. In some cases, involvement is subclinical on one side and symptomatic on the other.

Physical maneuvers – CTS symptoms are often provoked by activities that involve sustained flexing or extending the wrist or raising the arms, such as driving, reading, typing, and holding a telephone [1,3].

Some patients report temporary improvement in symptoms by shaking or wringing their hands or by placing them under warm running water [1].

Clinical course – The symptoms of CTS may be noted initially at night and the pain or paresthesias may awaken patients from sleep. As they progress, symptoms may also be noted during waking hours, especially during activities that require sustained arm positions or repetitive movements. In some cases, there is progression from intermittent to persistent sensory complaints and from paresthesias to sensory loss in the hand. Fixed sensory loss is usually a late finding characterized by a distinctive clinical pattern that involves the median-innervated fingers and spares the thenar eminence. This pattern occurs because the palmar sensory cutaneous nerve arises proximal to the wrist and passes over, rather than through, the carpal tunnel. (See "Carpal tunnel syndrome: Pathophysiology and risk factors", section on 'Anatomy'.)

Motor symptoms, including weakness, typically develop late and in patients with a more severe course. However, some patients with acute CTS, such as those with symptoms due to a bone fracture or other trauma, may report early weakness due to axonal injury.

For patients with mild symptoms, the clinical course of CTS may follow an alternating pattern with periods of remission and exacerbation [4]. (See "Carpal tunnel syndrome: Treatment and prognosis", section on 'Prognosis'.)

DIAGNOSIS AND EVALUATION — CTS should be suspected in patients with symptoms such as pain or paresthesia in the hand or examination findings of sensory loss or weakness in the distribution of the median nerve (figure 1) [3]. (See 'Clinical features' above.)

The diagnosis of CTS is clinical for patients with characteristic symptoms and signs. Electrodiagnostic and other diagnostic testing can be helpful to confirm or exclude CTS when the clinical diagnosis is uncertain [5]. Diagnostic testing is also useful for patients with moderate or severe symptoms (table 1) to gauge the severity of nerve compression and to aid in decisions regarding surgical intervention (algorithm 1). Stable patients with symptoms that are mild and classic for CTS may be followed clinically because up to two-thirds improve with nonsurgical treatment [6]. (See 'Electrodiagnostic testing' below and "Carpal tunnel syndrome: Treatment and prognosis", section on 'Initial nonsurgical treatment for most patients'.)

The combination of characteristic symptoms and signs and confirmatory electrodiagnostic testing appears to be most accurate for the diagnosis of CTS [7,8].

Clinical diagnosis — The likelihood of an accurate clinical diagnosis of CTS corresponds with the number of characteristic symptoms and provocative or mitigating factors listed as criteria for the diagnosis of CTS [3]. These include:

Characteristic symptoms

Dull, aching discomfort in the hand, forearm, or upper arm

Paresthesia in the hand

Weakness or clumsiness of the hand

Occurrence of any of these symptoms in the median distribution

Provocative factors

Sleep

Sustained hand or arm positions

Repetitive actions of the hand or wrist

Mitigating factors

Changes in hand posture

Shaking the hand

For patients with additional features suggestive of an alternative diagnosis and those with moderate to severe symptoms including sensory loss or weakness, we obtain additional diagnostic testing. (See 'Differential diagnosis' below and 'Diagnostic testing for patients with moderate to severe or atypical symptoms' below.)

Examination — Objective sensory and motor deficits corresponding to the median nerve–innervated regions of the hand may be present, but their absence does not rule out the diagnosis of CTS.

Sensation should be tested in all regions of both hands, forearms, and upper arms (figure 2). Objective sensory deficits on testing usually occur late in the course of CTS; they involve the median-innervated fingers but spare the thenar eminence [3]. This is a critical finding, as sensory loss over the thenar eminence suggests a median nerve lesion proximal to the carpal tunnel. (See "Carpal tunnel syndrome: Pathophysiology and risk factors", section on 'Anatomy'.)

Objective weakness can occur in severe or advanced CTS and is typically limited to muscles of the thenar eminence [3]. This manifests principally as weakness of thumb abduction and thumb opposition. Atrophy of the thenar eminence may be present. Weakness in other hand muscles may suggest a median or other nerve lesion proximal to the carpal tunnel.

Provocative maneuvers — Bedside tests performed as part of a clinical examination to elicit symptoms of CTS may improve the diagnostic yield of a clinical evaluation. Provocative maneuvers include the Phalen, Tinel, manual carpal compression, and hand elevation tests. These can be helpful when interpreted in the proper clinical context. However, the sensitivity and specificity of these provocative tests in isolation is moderate at best [9,10].

The Phalen maneuver is performed by having the patient bring the dorsal surfaces of the hands against each other to provide hyperflexion of the wrist while the elbows remain flexed (picture 1). Alternatively, the patient fully may flex the hands at the wrist with the elbow in full extension to provide traction on the median nerve. The flexed position is held for one minute. A positive Phalen sign is defined as pain and/or paresthesia in the median-innervated fingers. Meta-analyses have shown an average sensitivity of 68 percent and specificity of 73 percent for a positive Phalen test [10]. One prospective study found that Phalen test correlated with CTS severity [11].

The Tinel test (picture 2) involves firm percussion performed over the course of the median nerve just proximal to or on top of the carpal tunnel. A positive Tinel test is defined as pain and/or paresthesia of the median-innervated fingers that occurs with percussion over the median nerve. A positive Tinel sign may be less sensitive (50 percent) than the Phalen sign but has similar specificity (77 percent) [10].

The manual carpal compression, or Durkan test is performed by applying pressure over the transverse carpal ligament for 30 seconds (picture 3). Pain or paresthesia indicates a positive result. The average sensitivity and specificity of the manual carpal compression test are 64 and 83 percent, respectively [10].

The hand elevation test involves having the patient raise the hands above the head for one minute [12]. The test is positive if it reproduces the symptoms of CTS. The sensitivity and specificity may be similar to or slightly better than those reported for Tinel test and Phalen maneuvers, but few reports have compared these tests directly [12,13].

The upper limb neurodynamic test assesses for peripheral nerve mobility and can be used to identify patients with CTS [14,15]. Patients are instructed to abduct and externally rotate the shoulder, and flex the elbow, each at 90 degrees. Next, the patient supinates the forearm, extends the wrist and fingers, and abducts the thumb. A positive upper limb neurodynamic test suggests restriction of nerve mobility when CTS symptoms occur or worsen with elbow extension.

In a 2022 meta-analysis of 37 observational studies that assessed the diagnostic accuracy of provocative tests that included more than 2600 wrists of patients with CTS, the diagnostic performance of the hand elevation test was better than other provocative tests [16]. The diagnostic accuracies were:

Hand elevation test – odds ratio (OR) 128.6, 95% CI 40.6-407.1

Manual carpal compression – OR 15.8, 95% CI 3.8-66.4

Phalen test – OR 7.2, 95% CI 4.1-12.9

Tinel test – OR 5.3, 95% CI 3.5-8.1

Upper limb neurodynamic test – OR 1.8, 95% CI 0.6-5.2

However, the certainty of these findings is limited by the observational nature of the data, variable protocols used for individual tests, and the small number of studies assessing the upper limb neurodynamic test.

Diagnostic testing for patients with moderate to severe or atypical symptoms — We perform electrodiagnostic testing for CTS for all patients with atypical symptoms to confirm the diagnosis and for patients with symptoms that are moderate to severe (table 1) or that progress despite conservative treatment to aid in decisions regarding surgical intervention (algorithm 1).

Imaging of the median nerve with ultrasound or magnetic resonance imaging (MRI) is typically performed for patients with suspected mass lesions or those with atypical symptoms not explained by electrodiagnostic testing.

Electrodiagnostic testing — Electrodiagnostic testing with nerve conduction studies (NCS), often supplemented with needle electromyography (EMG), has a high sensitivity and specificity for confirming the diagnosis of CTS and for excluding other conditions in the differential diagnosis [5,17]. Electrodiagnostic testing is also useful for gauging the severity of median nerve injury because the extent of clinical symptoms may not always correlate with the severity of the injury to the median nerve.

The diagnosis of CTS may be confirmed by results from the NCS. Needle EMG is also performed to identify the integrity of motor units to help select patients for surgical treatment whenever symptoms or NCS findings are moderate to severe (table 1) [18-25]. As examples, EMG can provide objective evidence of persisting neuronal integrity in some severe cases when sensory and motor responses are absent on NCS; similarly, in some cases where NCS abnormalities are modest, EMG can show evidence of more severe active denervation.

In addition, EMG is warranted in patients with atypical symptoms to exclude other conditions such as polyneuropathy, plexopathy, and radiculopathy [18]. (See 'Differential diagnosis' below.)

Nerve conduction studies — The electrodiagnosis of CTS is made by the demonstration of impaired median nerve conduction across the carpal tunnel in the context of normal conduction elsewhere [1,26].

The NCS evaluation for CTS involves measurement of conduction velocity across the carpal tunnel as well as determination of the amplitude of sensory and motor responses to determine the severity of injury to the median nerve.

Impaired nerve conduction – Nerve compression results in damage to the myelin sheath and manifests as delayed distal latencies and slowed conduction velocities. Mild CTS may not produce any nerve conduction abnormalities. With increased compression of the median nerve, focal demyelination can occur. This may result in local conduction block and/or slowing of motor and sensory conduction across the wrist.

Axon loss – With sustained or more severe compression, axon loss may also occur, resulting in a reduction of the median nerve compound motor or sensory nerve action potential amplitude. Sensory fibers seem to be more sensitive to compression than motor fibers. As a result, sensory fibers typically demonstrate changes on NCS earlier than do motor fibers.

Specific components of NCS to evaluate CTS include:

Sensory conduction studies involve stimulating branches of the median nerve at the wrist and recording sensory response from digit two or three, depending on clinical symptoms. Results are compared with sensory responses of other nerves including the ulnar (stimulating the wrist and recording at digit five) and radial (stimulating at the lateral radius and recording at the snuffbox) [1].

Motor conduction studies most often record from the abductor pollicis brevis muscle, although other muscles can also provide diagnostic information. Results obtained are compared with age-dependent normal values as well as with other nerves of the same hand or the contralateral hand. Comparative motor testing typically includes the ulnar nerve (recording from the abductor digiti minimi while stimulating at the wrist and at the elbow above and below the ulnar groove) [1].

Additional comparison studies should be used for patients who have normal routine NCS in the setting of clinical findings suggestive of CTS [1]. These may include testing the second lumbrical (median) versus interossei (ulnar) distal motor latencies, evaluating sensory latencies at digit four by stimulating the median and ulnar nerves at the wrist individually at identical distances, and comparing palm-to-wrist peak latencies of median and ulnar nerves, each recorded 8 cm from the stimulating electrodes.

In a 2002 systematic review of prospective studies, the sensitivity of various NCS for CTS ranged from 56 to 85 percent, and the specificity ranged from 94 to 99 percent [5,17]. In a later study of 99 patients without confounding neurologic disorders who met clinical criteria for CTS, NCS (including median and ulnar palmar mixed-nerve studies) were normal in 25 percent [27].

Anomalous innervations may result in atypical findings during electrodiagnostic testing. One of the most frequently encountered variations during evaluation of CTS is a median-to-ulnar anastomosis. The Martin–Gruber anastomosis describes a subgroup of motor fibers that split from the median nerve in the forearm and join the ulnar nerve to innervate the intrinsic muscles of the hand. The Riche–Cannieu anastomosis describes a connection between the recurrent branch of the median nerve in the hand and the deep branch of the ulnar nerve and results in ulnar innervation of the thenar hand muscles. (See "Carpal tunnel syndrome: Pathophysiology and risk factors", section on 'Anatomy'.)

With median nerve studies in patients with CTS and median-to-ulnar anastomoses, the amplitude of the compound muscle action potential is higher with stimulation at the proximal elbow site than with stimulation at the wrist [28]. Median nerve conduction velocities may be surprisingly fast in the forearm and typically slow across the wrist [28,29].

Electromyography — EMG is a useful component of electrodiagnostic testing in CTS to exclude other conditions, such as polyneuropathy, plexopathy, and radiculopathy, and to assess severity of CTS if surgical decompression is being considered [1]. EMG is not necessary for patients who have classic signs and symptoms of CTS and confirmatory findings on NCS when there is no suspicion for other etiologies and surgery is not contemplated.

EMG assesses for evidence of pathologic changes in the muscles innervated by the median nerve. When secondary axonal loss is present, EMG may reveal either active denervation (eg, spontaneous activity such as fibrillation potentials, positive sharp waves, and fasciculation potentials) or chronic changes that indicate denervation with subsequent reinnervation (eg, changes in motor unit action potential amplitudes, durations, and recruitment). Such findings are supportive of the diagnosis of CTS in the context of normal findings in both nonmedian-innervated muscles and proximal median nerve-innervated muscles.

Specific components of EMG to evaluate CTS include [1]:

Abductor pollicis brevis

Two or more C6–C7 innervated muscles (eg, pronator teres, triceps brachii, extensor digitorum communis) to look for evidence of cervical radiculopathy

Additional muscles are typically evaluated if the abductor pollicis brevis is abnormal [1]. This includes median-innervated muscles proximal to the carpal tunnel (eg, flexor carpi radialis, pronator teres, flexor pollicis longus) to exclude a proximal median neuropathy and nonmedian-innervated muscles (eg, first dorsal interosseous, extensor indicis proprius) to rule out brachial plexopathy, polyneuropathy, and C8 to T1 radiculopathy.

Imaging — Imaging of the median nerve with ultrasound or MRI is typically performed for patients with a suspected structural abnormality at the carpal tunnel or those with atypical symptoms not explained by electrodiagnostic testing [30-32]. Imaging may help to identify anatomic variants associated with CTS such as a tumor, ganglion cyst, bifid median nerve, persistent median artery, or bone or joint disease and can also show median nerve abnormalities such as edema or alterations in blood flow [33].

Neuromuscular ultrasound (image 1) may approach the diagnostic sensitivity of electrodiagnostic testing for CTS when performed by a skilled practitioner [34]. Ultrasound is typically a quicker test to perform and more comfortable for patients. Ultrasound may show imaging evidence suggestive of CTS such as increased median nerve cross-sectional area compared with controls [35-39]. However, optimal cross-sectional area cut-off for the diagnosis as well as the sensitivity and specificity of this technique have varied in these reports [40,41]. In a systematic review of the literature, the four highest-quality studies used cut-offs of 8.5 to 10 mm2 for the diagnosis [41]. The sensitivities ranged from 65 to 97 percent and the specificities ranged from 73 to 98 percent. Caution is warranted when interpreting ultrasound in older adults, as the sensitivity appears to be significantly lower in patients 80 years and older compared with those younger than 65 years [42,43]. In addition, ultrasound does not provide presurgical physiologic information about the severity of nerve dysfunction at the median nerve or assess for alternative causes of clinical symptoms (eg, radiculopathy).

Ultrasound may be performed to guide treatment with glucocorticoid injections or minimally invasive surgical release. (See "Carpal tunnel syndrome: Treatment and prognosis", section on 'Glucocorticoid injection' and "Surgery for carpal tunnel syndrome", section on 'Ultrasound-guided ultra-minimally invasive techniques'.)

Instructional videos demonstrating proper performance of the ultrasound examination of the wrist and related pathology can be found at the website of the American Medical Society for Sports Medicine. Registration must be completed to access these videos, but no fee is required.

MRI can detect abnormalities of the median nerve, flexor tendons, vascular structures, and transverse carpal ligament in the region of the carpal tunnel [44,45]. MRI can identify soft tissue abnormalities and may be useful for unusual cases to rule out a mass lesion. However, the diagnostic utility of MRI for other cases of CTS remains uncertain.

DIFFERENTIAL DIAGNOSIS — The differential diagnosis of CTS includes neurologic, musculoskeletal, and vascular conditions that can present with pain, paresthesia, sensory loss, or weakness involving the arm or hand [1,30,46,47].

Conditions that may present with symptoms isolated to or predominating in the median nerve include cervical spine disorders, brachial plexopathy, proximal lesions of the median nerve, and various types of polyneuropathy.

Cervical radiculopathy – The most common disorder than can mimic CTS is cervical radiculopathy, particularly with C6 or C7 nerve root involvement [1]. The symptoms may include arm pain and paresthesia that resemble those of CTS. Features that favor cervical radiculopathy include [1,30]:

The presence of neck pain that radiates into the shoulder and arm

Exacerbation of symptoms with neck movement

Reduced reflexes (ie, biceps, brachioradialis, and triceps)

Weakness of proximal arm muscles involving elbow flexion, extension, and arm pronation

Sensory loss in the forearm or medial palm

C8 and T1 root lesions may also mimic the symptoms or signs of CTS, predominantly involving motor dysfunction.

Although clinical sensory loss may be present in cervical radiculopathy, the sensory nerve action potentials remain unaffected in root lesions due to the more distal location of the sensory nerve cell body. This is an important distinguishing feature from peripheral nerve lesions. (See "Overview of nerve conduction studies", section on 'Sensory nerve conduction' and "Clinical features and diagnosis of cervical radiculopathy", section on 'Electrodiagnostic studies'.)

Median neuropathy in the forearm – Median neuropathy proximal to the carpal tunnel may occur in the forearm where the nerve passes through the pronator teres muscle. Patients may present with forearm pain and sensory loss involving the entire lateral palm. Features that favor a forearm localization include the findings of sensory loss over the thenar eminence (typically spared in CTS) and weakness of more proximal median-innervated muscles (thumb flexion, wrist flexion, and arm pronation) [1]. However, electrodiagnostic studies are often required to localize the site of compression appropriately.

Cervical spondylotic myelopathy and cervical polyradiculopathy – Cervical spine myelopathy or polyradiculopathy may present with symptoms similar to CTS but usually involves bilateral sensory loss and motor dysfunction in the hands and may also include dysfunction in nonmedian nerve territories [47]. (See "Cervical spondylotic myelopathy", section on 'Clinical presentation'.)

Brachial plexopathy – Patients with brachial plexopathies may sometimes manifest with predominant symptoms suggestive of dysfunction to an individual nerve, such as the axillary, long thoracic, anterior interosseous, radial, median, or a cutaneous nerve. However, the examination findings more commonly reveal weakness, sensory loss, or diminished reflexes outside the distribution of the median nerve and usually involve more than one spinal segment. (See "Brachial plexus syndromes".)

Other conditions characterized by multifocal or diffuse symptoms may sometimes be included in the differential diagnosis of CTS when presenting early with prominent median nerve symptoms. This includes central nervous system lesions, motor neuron disease, compartment syndrome involving the forearm or hand, fibromyalgia, osteoarthritis and inflammatory arthropathy involving the small joints of the hand, Raynaud phenomenon, and ligamentous injury, which can present in ways similar to CTS, although for the most part these entities are easily distinguished.

Ischemic stroke – Small ischemic strokes restricted to the cortical region of the primary motor cortex responsible for movement of the contralateral hand may mimic the weakness seen in CTS [48,49]. However, patients with stroke in this "hand knob" region typically report sudden onset of symptoms, lack pain, and have weakness of muscles innervated by median and radial and/or ulnar nerves on examination. (See "Clinical diagnosis of stroke subtypes".)

Motor neuron disease – Amyotrophic lateral sclerosis (ALS) or other forms of motor neuron disease can present with asymmetric hand involvement that may predominantly involve the thenar hand intrinsic muscles. The absence of pain argues against CTS. More importantly, ALS essentially never presents with weakness of a single muscle. (See "Clinical features of amyotrophic lateral sclerosis and other forms of motor neuron disease", section on 'Initial presentation'.)

Forearm or hand compartment syndrome – Patients with compartment syndrome can present as pain with passive stretch and a firm compartment palpated over the forearm or hand; it may be confused with CTS or other peripheral nerve injury if pain and sensory deficits involve the median nerve territory. However, the distribution of pain may be more widespread with progression of compartment syndrome when the ulnar and dorsal sensory radial nerves are also compromised [46]. In addition, acute compartment syndrome typically occurs in the setting of trauma, which helps differentiate it from CTS. (See "Acute compartment syndrome of the extremities", section on 'Clinical features'.)

Fibromyalgia – Symptoms in fibromyalgia frequently include numbness and tingling radiating down the arm. However, the sensory symptoms may not be restricted to the median nerve and the chronic widespread musculoskeletal pain and fatigue that is typical of fibromyalgia is unusual in patients with CTS. (See "Clinical manifestations and diagnosis of fibromyalgia in adults" and "Differential diagnosis of fibromyalgia".)

Arthritis – Patients with osteoarthritis and rheumatoid arthritis or other inflammatory arthropathies may present with wrist pain that radiates to or involves the hand. Features suggestive of arthritis over CTS include bilateral involvement, involvement of joints other than the wrist, and joint swelling. (See "Clinical manifestations and diagnosis of osteoarthritis", section on 'Hand' and "Clinical manifestations of rheumatoid arthritis", section on 'Hands'.)

Osteoarthritis and rheumatoid arthritis are also risk factors for CTS. Inflammatory changes from these conditions may cause localized symptoms as well as CTS due to anatomic compression at the carpal tunnel. (See "Carpal tunnel syndrome: Pathophysiology and risk factors", section on 'Arthritis'.)

Raynaud phenomenon – The vasoconstriction that occurs with the Raynaud phenomenon (RP) may produce digital pain and paresthesia. However, RP symptoms occur typically as episodes provoked by cold temperatures or stress and are accompanied by skin pallor or cyanosis. (See "Clinical manifestations and diagnosis of Raynaud phenomenon", section on 'Signs and symptoms of Raynaud phenomenon'.)

Pain from a ligamentous disruption – The pain that accompanies ligamentous injury of the wrist may be similar to pain in CTS but is typically more localized and does not involve the volar surface of the wrist or thenar region seen in CTS. (See "Evaluation of the adult with subacute or chronic wrist pain", section on 'Differential diagnosis by regions of the wrist'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Carpal tunnel syndrome".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or email these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

Basics topics (see "Patient education: Carpal tunnel syndrome (The Basics)" and "Patient education: Hand pain (The Basics)")

SUMMARY

Clinical features – The hallmark of classic carpal tunnel syndrome (CTS) is pain or paresthesia (numbness and tingling) in a distribution that includes the median nerve territory, with involvement of the first three digits and the radial half of the fourth digit (figure 1). (See 'Clinical features' above.)

Diurnal character – The symptoms are typically worse at night and characteristically awaken affected patients from sleep.

Location of pain – The pain and paresthesia may be localized to the wrist, involve the entire hand, or radiate proximally to as high as the shoulder (figure 2).

Provoking features – CTS symptoms are often provoked by activities that involve flexing or extending the wrist or raising the arms.

Severe manifestations – Fixed sensory loss is usually a late finding characterized by a distinctive clinical pattern that involves the median-innervated fingers and spares the thenar eminence. In severe CTS, motor involvement leads to complaints of weakness or clumsiness when using the hands. Clinical signs may include weakness of thumb abduction and opposition and atrophy of the thenar eminence.

Clinical diagnosis – The clinical diagnosis of CTS is made in patients with pain or paresthesia in the hand or examination findings of sensory loss or weakness in the distribution of the median nerve (figure 1). (See 'Diagnosis and evaluation' above.)

Provocative maneuvers for CTS include the Phalen, Tinel, manual carpal compression, hand elevation, and upper limb neurodynamic tests. These can be helpful when interpreted in the proper clinical context. However, the sensitivity and specificity of these tests are moderate at best. (See 'Provocative maneuvers' above.)

Electrodiagnostic confirmation and evaluation – Electrodiagnostic testing is warranted for all patients who have atypical symptoms to confirm the diagnosis and for patients with symptoms that are moderate to severe (table 1) or that progress despite conservative treatment to aid in decisions regarding surgical intervention (algorithm 1). (See 'Diagnostic testing for patients with moderate to severe or atypical symptoms' above.)

The electrodiagnosis of CTS is made by the demonstration of impaired median nerve conduction across the carpal tunnel in the context of normal conduction elsewhere. Electromyography is used along with nerve conduction studies to exclude other conditions, such as polyneuropathy, plexopathy, and radiculopathy, and to assess severity CTS if surgical decompression is being considered. (See 'Electrodiagnostic testing' above.)

Differential diagnosis – The differential diagnosis of CTS includes neurologic, musculoskeletal, and vascular conditions that can present with pain, paresthesia, sensory loss, or weakness involving the arm or hand. The most common disorder than can mimic CTS is cervical radiculopathy, particularly with C6 or C7 nerve root involvement. (See 'Differential diagnosis' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Kevin Scott, MD, who contributed to earlier versions of this topic review.

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Topic 5288 Version 38.0

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