Carpal Tunnel Syndrome Clinical Presentation

The patient's history often is more important than the physical examination in making the diagnosis of carpal tunnel syndrome (CTS).

• Numbness and tingling

  • Among the most common complaints, patients will reveal that their hands fall asleep or that things slip from their fingers without their noticing (loss of grip, dropping things); numbness and tingling also are commonly described.

  • Symptoms are usually intermittent and are associated with certain activities (eg, driving, reading the newspaper, crocheting, painting). Nighttime symptoms that wake the individual are more specific to CTS, especially if the patient relieves symptoms by shaking the hand/wrist. Bilateral CTS is common, although the dominant hand is usually affected first and more severely than the other hand.

  • Complaints should be localized to the palmar aspect of the first to the fourth fingers and the distal palm (ie, the sensory distribution of the median nerve at the wrist). Numbness existing predominantly in the fifth finger or extending to the thenar eminence or dorsum of the hand should suggest other diagnoses. A surprising number of CTS patients are unable to localize their symptoms further (eg, whole hand/arm feeling dead). This generalized numbness may indicate autonomic fiber involvement and does not exclude CTS from the diagnosis.

• Pain

  • The sensory symptoms above commonly are accompanied by an aching sensation over the ventral aspect of the wrist. This pain can radiate distally to the palm and fingers or, more commonly, extend proximally along the ventral forearm.

  • Pain in the epicondylar region of the elbow, upper arm, shoulder, or neck is more likely to be due to other musculoskeletal diagnoses (eg, epicondylitis) with which CTS commonly is associated. This more proximal pain also should prompt a careful search for other neurologic diagnoses (eg, cervical radiculopathy).

• Autonomic symptoms

  • Not infrequently, patients report symptoms in the whole hand. Many patients with CTS also complain of a tight or swollen feeling in the hands and/or temperature changes (eg, hands being cold/hot all the time).

  • Many patients also report sensitivity to changes in temperature (particularly cold) and a difference in skin color. In rare cases, there are complaints of changes in sweating. In all likelihood, these symptoms are due to autonomic nerve fiber involvement (the median nerve carries most of the autonomic fibers to the hand).

• Weakness/clumsiness - Loss of power in the hand (particularly for precision grips involving the thumb) does occur; in practice, however, loss of sensory feedback and pain is often a more important cause of weakness and clumsiness than is loss of motor power per se.

Clinical examination is important to rule out other neurologic and musculoskeletal diagnoses; however, the examination often contributes little to the confirmation of the diagnosis of carpal tunnel syndrome (CTS).

• Sensory examination

  • Abnormalities in sensory modalities may be present on the palmar aspect of the first 3 digits and radial one half of the fourth digit. Semmes-Weinstein monofilament testing or 2-point discrimination may be more sensitive in picking this up; however, in the author's experience, pinprick sensation is as good as any test.

  • Sensory examination is most useful in confirming that areas outside the distal median nerve territory are normal (eg, thenar eminence, hypothenar eminence, dorsum of first web space).

• Motor examination - Wasting and weakness of the median-innervated hand muscles (LOAF muscles) may be detectable.

  • L - First and second lumbricals

  • O - Opponens pollicis

  • A - Abductor pollicis brevis

  • F - Flexor pollicis brevis

• Special tests - No good clinical test exists to support the diagnosis of CTS.

  • Hoffmann-Tinel sign

    • Gentle tapping over the median nerve in the carpal tunnel region elicits tingling in the nerve's distribution.

    • This sign still is commonly looked for, despite the low sensitivity and specificity.

  • Phalen sign

    • Tingling in the median nerve distribution is induced by full flexion (or full extension for reverse Phalen) of the wrists for up to 60 seconds

    • This test has 80% specificity but lower sensitivity.

  • The carpal compression test ^[25]

    • This test involves applying firm pressure directly over the carpal tunnel, usually with the thumbs, for up to 30 seconds to reproduce symptoms.

    • Reports indicate that this test has a sensitivity of up to 89% and a specificity of 96%.

  • Palpatory diagnosis

    • This test involves examining the soft tissues directly overlying the median nerve at the wrist for mechanical restriction.

    • This palpatory test has been noted to have a sensitivity of over 90% and a specificity of 75% or greater.

  • The square wrist sign

    • The ratio of the wrist thickness to the wrist width is greater than 0.7.

    • This test has a modest sensitivity/specificity of 70%.

• Several other tests have been advocated, but they rarely provide additional information beyond that which the Phalen and square wrist signs provide.

Note that carpal tunnel syndrome (CTS) is associated with many different factors. ^[26] In particular, the more the hand and wrist are used, the greater the symptoms. This observation does not necessarily mean that using the hand and wrist causes the syndrome or that more median nerve damage ensues. Association should not be assumed to signify causation.

• Demographics

  • Increasing age

  • Female sex

  • Increased body mass index (BMI), especially a recent increase

  • Square-shaped wrist

  • Short stature

  • Dominant hand

  • Race (white)

• Genetics

  • A strong family susceptibility exists and is probably related to multiple inherited characteristics (eg, square wrist, thickened transverse ligament, stature).

  • A number of inherited medical conditions also are associated with CTS (eg, diabetes, thyroid disease, hereditary neuropathy with liability to pressure palsies).

• Medical conditions

  • Wrist fracture (Colles)

  • Acute, severe flexion/extension injury of wrist

  • Space-occupying lesions within the carpal tunnel (eg, flexor tenosynovitis, ganglions, hemorrhage, aneurysms, anomalous muscles, various tumors, edema)

  • Diabetes

  • Thyroid disorders (usually myxedema)

  • Rheumatoid arthritis and other inflammatory arthritides of the wrist

  • Recent menopause (including post-oophorectomy) ^[20]

  • Renal dialysis

  • Acromegaly

  • Amyloidosis

• Vocational/avocational ^{[26, 27, 28]} - Activities that may be associated with CTS (particularly in combination) involve the following:

  • Prolonged, severe force through the wrist

  • Prolonged, extreme posture of the wrist

  • High amounts of repetitive movements

  • Exposure to vibration and/or cold

• Other factors

  • Lack of aerobic exercise

  • Pregnancy and breastfeeding

  • Use of wheelchairs and/or walking aids

A study by Fernández-Munoz et al reported that in women with CTS, the following predict the severity of hand pain ^[29] :

• Function

• Thumb-middle finger pinch tip grip force

• Thumb-little finger pinch tip grip force

• Depression

• Pressure pain threshold (radial nerve)

• Pressure pain threshold (carpal tunnel)

• Heat pain threshold (carpal tunnel)

The study, which involved 224 women with CTS, indicated that these factors are responsible for 36.5% of variance in pain intensity.

A study by Yeh et al indicated that in patients who suffer a distal radius fracture, CTS is more likely to develop, within a 9-month postfracture period, in those who undergo open reduction and internal fixation (ORIF). The investigators also reported that the presence of diabetes mellitus was significantly associated with the development of CTS within 9 months following distal radius fracture (adjusted hazard ratio 2.76). ^[30]