Carpal Tunnel Syndrome

Aka: Carpal Tunnel Syndrome, Median Neuropathy, Carpal Tunnel

1. See Also
   1. Overuse Syndromes of the Hand and Wrist
   2. Peripheral Nerve Injury
2. Epidemiology
   1. Bilateral in 50% of cases
   2. Associated with workplace repetitive hand activities
   3. Hand Paresthesias occur in 30% of computer users
      1. Only 10% of these meet criteria for Carpal Tunnel
      2. Only 3.5% of these have abnormal EMGs
      3. Stevens (2001) Neurology 56:1568-70
3. Pathophysiology: Compression of Median Nerve
   1. Occurs between transverse carpal ligament
   2. Inflamed and enlarged synovial lining of flexor tendons
4. Risk Factors
   1. Repetitive motion of hand and wrist
      1. Most common cause, and typically work related
   2. Local wrist or hand trauma
   3. Obesity
5. Associated Conditions
   1. Hypothyroidism
   2. Diabetes Mellitus
   3. Acromegaly
   4. Rheumatoid Arthritis
   5. Gouty Arthritis
   6. Lyme Disease
   7. Amyloidosis
   8. Multiple Myeloma
   9. Edematous condition
      1. Third trimester of Pregnancy
         1. Symptoms subside after delivery
      2. Congestive Heart Failure
      3. Renal Failure
   10. Aberrant or Anomalous muscles in wrist
       1. Proximal lumbrical insertion
       2. Distal extension of flexor superficialis muscle
       3. Persistent thrombosed median artery
       4. Abnormal palmaris longus tendon
       5. Ganglion Cyst
       6. Lipoma
   11. Double-Crush Syndrome
6. Symptoms
   1. Image: Median Nerve Sensory Innervation
      1. 
   2. Paresthesias along Median Nerve course (palmar surface)
      1. Electrical Sensation or Dysesthesias
      2. Commonly involves only Index and Middle fingers
         1. May affect all median innervated 3.5 fingers
   3. Pain in distal, palmar surface of wrist or arm
      1. Distal radiation into thumb, index and middle finger
      2. Proximal radiation into arm, Shoulder and neck
   4. Gradually increasing night pain (95% of patients)
      1. Increase in wrist swelling with inactivity
      2. Wrist flexion at night (may awaken patient)
   5. Numbness
      1. Describes "poor circulation" and "Stiffness"
      2. Despite which hand feels warm
   6. Weakness and Clumsiness of hand
      1. Decreased grip strength
   7. Timing
      1. Spontaneous onset
   8. Provocative of Sensory and Motor Symptoms
      1. Precipitated by Typing, Painting, and wrist motion
   9. Palliative
      1. Shaking or moving hand
      2. Allow hand to hang down
      3. Flick Sign
         1. Flicking wrist as if shaking down thermometer
7. Signs
   1. Classic exam findings have poor predictive value and are falling out of favor
      1. Tinel's sign (44-70% sensitive, 94% specific)
      2. Phalen's Maneuver (70-80% sensitive, 80% specific)
   2. Flick Test (93% Sensitive, 96% Specific)
   3. Sensory deficit over Median Nerve
      1. Hypalgesia in Median Nerve distribution has highest Likelihood Ratio
      2. Two Point Discrimination <6 mm with caliper (33% Sensitive, 100% Specific)
   4. Carpal Compression Test (90% sensitive, 90% specific)
   5. Thenar muscle atrophy
      1. Associated with decreased grip strength
      2. Only present in severe, long-standing disease
      3. Other hand and wrist neuropathies will cause this as well
   6. Tourniquet Test (Not sensitive, not specific)
      1. Inflate Blood Pressure Cuff on upper arm above SBP
      2. Positive Test
         1. Paresthesias and Numbness after inflation <1 minute
   7. Abductor pollicis brevis weakness
      1. Abduct thumb perpendicular to palm against examiner's resistance
   8. Pain not worse with resisted motion
   9. Full range of motion intact
8. Diagnosis
   1. Findings with highest predictive value
      1. Classic hand symptoms in median distribution
      2. Decreased Pain Sensation at index palmar surface
      3. Weak thumb abduction
   2. References
      1. D&#39;Arcy (2000) JAMA 283:3110-7
9. Differential Diagnosis
   1. Flexor carpi radialis Tenosynovitis
      1. Extends from proximal 1st Metacarpal to medial epicondyle
   2. Raynaud Syndrome
   3. Other Neuropathy
      1. Cervical Radiculopathy (C6 nerve)
      2. Median Nerve compression at elbow
      3. Ulnar Tunnel (or Cubital Tunnel)
   4. Degenerative Joint Disease
      1. Wrist Osteoarthritis
      2. Thumb carpometacarpal Osteoarthritis
10. Radiology: Wrist XRay
    1. Evaluate for local bony abnormality
11. Diagnostics
    1. Nerve Conduction Studies (Electromyography, EMG)
       1. Indicated in unclear cases or in pre-surgical assessment of severity
       2. Delayed electrical conduction across wrist at the Median Nerve
       3. Efficacy: 56-85% sensitive, 94% specific
    2. Other diagnostic studies (CT, MRI, Ultrasound) are not typically indicated
12. Management: General Measures (Conservative)
    1. Efficacy
       1. Spontaneous resolution with Placebo: 50%
          1. Goodyear-Smith (2004) Ann Fam Med 2:267-73
       2. Short-term: 80% respond
       3. Long-term: 80% of responders recur after one year
    2. Eliminate cause and modify work conditions
       1. Avoid repetitive trauma
       2. Avoid the extremes of wrist flexion or extension
       3. Avoid vibratory tool use
       4. Employ ergonomics (wrist rest, adjust chair/desk, voice recognition software)
    3. Wrist Splint or Wrist brace (neutral position)
       1. Polypropylene occupational wrist splint
       2. Maintains wrist in neutral position
          1. Avoid cock-up (hyperextension) brace
       3. Most effective if started early (within 3 months)
       4. Wear during both day and night (best results)
          1. Burke (1994) Arch Phys Med Rehabil 75:1241-4
          2. Sevim (2004) Neurol Sci 25:48-52
    4. Wrist and Hand Exercises
       1. Brief (1 minute)
       2. Intermittently done during or after work
    5. Local or Systemic Corticosteroid
       1. Carpal Tunnel Steroid Injection
          1. As effective as surgery
          2. Ly-Pen (2005) Arthritis Rheum 52:612-9
       2. Consider Systemic Corticosteroids
          1. First: Prednisone 20 mg PO qd for 14 days
          2. Next: Prednisone 10 mg PO qd for 14 days
          3. Chang (1998) Neurology 51:390-3
    6. Local Ultrasound
       1. Six weeks of therapy provides up to 6 months relief
       2. Reference
          1. Ebenbickler (1998) BMJ 316:731-5
    7. NSAIDs (e.g. Ibuprofen)
    8. Pyridoxine may be indicated in pregnancy
       1. Dose: Pyridoxine 25-50 mg PO tid
       2. Unproven benefit
       3. Reference
          1. (1993) Can Fam Physician, 39:2122-7
13. Management: Surgical release transverse carpal ligament
    1. Indications
       1. Persistent symptoms refractory to above
       2. Progressive motor weakness
    2. Efficacy
       1. Results in prompt, permanent pain relief
       2. Very effective in 66% of patients
       3. May be effective even if EMG normal
       4. References
          1. Katz (2001) Arthritis Rheum 44:1184-93
          2. Gerritsen (2001) Br J Surg 88:1285-95
    3. Course
       1. Sensory, Motor function improvement may take months
    4. Adverse affects
       1. No Disability from sectioning transverse ligament
       2. Residual discomfort may continue from Tenosynovitis
    5. Complications
       1. Median Nerve branch injury
       2. Hypertrophic Scar
       3. Superficial Palmar ArchLaceration
14. References
    1. D&#39;Arcy (2000) JAMA 283(23): 3110-7
    2. Katz (1994) Am Fam Physician 49(6):1371-9
    3. Keith (2009) J Am Acad Orthop Surg 17(6): 389-96
    4. Keith (2009) J Am Acad Orthop Surg 17(6): 397-405
    5. LeBlanc (2011) Am Fam Physician 83(8): 952-8
    6. Viera (2003) Am Fam Physician 68(2):265-72