CARPAL TUNNEL SYNDROME


I. Definition and pathophysiology

  1. A neuropathy of the median nerve, caused by entrapment in the carpal tunnel
  2. Etiologic factors:
    1. Overuse (most common)
    2. Hypothyroidism
    3. Diabetes mellitus
    4. Arthritis
    5. Pregnancy

I. Diagnosis:

  1. Primarily clinical.  Typical symptoms:
    1. Paresthesias and decreased sensation in territory of the median nerve (thumb, index, and middle fingers and lateral aspect of ring finger)
    2. Weakness in affected hand and thenar muscule wasting (usually only if severe)
    3. Pain can occur proximal to wrist
    4. Pain in the hand is not common, particularly not on the ulnar side of the hand or the dorsal aspect
  2. Provocative tests
    1. Tinel's test (reproduction of symptoms with tapping over median nerve at the wrist): Sensitivity 28-73%, specificity 44-95%
    2. Phalen's test (reproduction of symptoms by pressing dorsal aspects of hands together in bilateral wrist flexion): Sensitivity 46-80%, specificity 24-92%
    3. "Wrist flexion/nerve compression" test (patient flexes wrist to 60' and examiner provides constant digital pressure w/one thumb over the median nerve at the carpal tunnel for up to 30 seconds)-Had sig. higher sensitivity & specificity in identifying nerve conduction study-proven CTS compared with Phalen's and Tinel's tests (J. Bone Joint Surg. Br. 80-B:493, 1998--JW)
  3. Electrodiagnostic studies can demonstrate abnormalities (severity of findings predicts likelihood of relief of symptoms with surgery)

II. Treatment:

  1. Wrist splinting for up to 1 month-Proven benefit in controlled trials
    1. Full-time bracing is associated with better relief than nighttime-only use
  2. Corticosteroids
    1. Injected corticosteroids
      1. Injection just proximal to the carpal tunnel of methylprednisolone (vs. injection of placebo) associated with significantly lower symptom scores at 12mos in a randomized trial of 30 pts with CTS (BMJ 319:884, 1999--JW)
      2. No clinical trials on benefit of repeated steroid injections as of 2012
    2. Oral corticosteroids
      1. Only prednisolone (20mg/d x 2wks then 10mg/d x 2 wks) resulted in sig. improved sx scores c/w placebo in a trial 73 pts with CTS confirmed with electrodiagnostic studies w/o obvious underlying causes, e.g. hypothyroidism, pregnancy, or DM. Other comparison tx's were trichlormethiazide, a diuretic, or tenoxicam, an NSAID) (Neurol. 51:390, 1998--JW)
    3. Comparison of oral vs. injected corticosteroids
      1. 60 pts with CTS randomized to 15mg methylprednisolone injected into carpal tunnel vs. oral methylprednisolone 25mg/d x 10d; both groups had sig. improvement in sx scores at 2wks but only injection group had sig. improvement at 3mos (Neurol. 56:1565, 2001--JW)
  3. Ultrasound QD x 10d then BIW x 5wks in mild-mod CTS was sig. better than a "sham" placebo tx (satisfactory improvement in 68% vs. 38% of cases at end of tx) (BMJ 316:731, 1998--AFP)
  4. Carpal tunnel release surgery
    1. In a randomized trial of 176 pts with severe CTS (confirmed by electrodiagnostic testing), surgery vs. nightly wrist splinting symptom scores at 18mos were sig. better in surgery group (JAMA 288:1245, 2002--JW)
    2. In a study in 101 pts with CTS (163 wrists total) unresponsive to NSAIDs and splinting randomized to surgery vs. local corticosteroid injection, the surgery wrists had sig. greater improvement in sx but there were no sig. diffs. at 6mos or 12mos (Arth. Rheum. 52:612, 2005--JW)
    3. Surgery found to provide better symptom relief than splinting after 1y in a 2008 Cochrane review
  5. Yoga
    1. 42 pts w/CTS randomized to upper-body yoga x 8wks vs. wrist splinting. At 8wks, yoga group had sig. > improvement in grip strength and pain c/w controls; no diff. in median n. conduction time (JAMA 280:1601, 1998)
  6. No known benefit from NSAIDs
(Sources include Core Content Review of Family Medicine, 2012)