Lippincott Nursing Pocket Card

Carpal Tunnel Syndrome

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Carpal Tunnel Syndrome

Carpal tunnel syndrome (CTS) is caused by compression of the median nerve along the carpal tunnel and is characterized by symptoms such as numbness, tingling, hand and arm pain, and muscle dysfunction (Kothari, 2017). CTS is a common disorder affecting approximately 3.8% of the population and results in a significant number of lost days of work and productivity (Durham & VanRavenstein, 2017). Nurses with knowledge of CTS, including risk factors, diagnosis, treatment and education, can improve patient outcomes.

Pathophysiology (Durham & VanRavenstein, 2017)

The median nerve provides sensation to the thumb, index finger, middle finger, and in some people, the ring finger. The median nerve travels down the forearm and enters the hand through a narrow tunnel formed by the bones of the wrist and the transverse carpal ligament. Injury, inflammation, or swelling in this area may cause compression of the median nerve which can result in symptoms of carpal tunnel syndrome.

Causes (Kothari, 2017)

  • Inflammation or thickening of the flexor tendons surrounding the median nerves
  • Fibrosis surrounding the flexor tendons
  • Congenitally small anatomic space within the carpal tunnel
  • Lesions, cysts, or neoplasms that compress the median nerve
  • Systemic illnesses that cause edema or inflammation, such as rheumatoid arthritis

Risk Factors (Kothari, 2017; Graham et al., 2016)

Risk Factors for Carpal Tunnel Syndrome*
Obesity Rheumatoid Arthritis Genetic predisposition
Female gender Hypothyroidism Aromatase inhibitor use
Peri-menopause Tendonitis Trauma
Pregnancy – symptoms often resolve after delivery Preexisting median mononeuropathy Workplace factors (repetition, forceful exertion, vibration)
Diabetes mellitus Connective tissue diseases High hand/wrist repetition rate

*Assess patients for risk factors but note that the presence of only one does not rule-in CTS. Studies support that physical activity is associated with a decreased risk of developing CTS.

Symptoms (Durham & VanRavenstein, 2017)

  • Paresthesia: numbness or tingling of the fingers, particularly the thumb, index finger, middle finger, and half of the ring finger; symptoms often worsen at night due to relaxation of the wrist into a flexed position
  • Pain: dull ache in the hand, forearm, or upper arm (pain may or may not be present)
  • Weakness or clumsiness of the hand
  • Swelling
  • Symptoms may affect entire hand, and less frequently radiate into the forearm, above the elbow and into the shoulder
  • Patient may shake the hand or flick the wrist to alleviate symptoms
  • Symptoms may be brought on by movements of the hand that cause flexion or extension of the wrist or raising the arms such as driving, reading, typing, and holding a telephone (Kothari, 2018)

Physical Examination

  • Assess the patient for (Durham & VanRavenstein, 2017):
    • Edema
    • Signs of trauma or injury such as abrasions or ecchymosis
    • Bony deformities suggesting rheumatoid arthritis such as ulnar deviation of the wrist and swan neck deformity
    • Wrist deformities suggesting osteoarthritis
  • Test sensation in all areas of the hand, forearm, and upper arm (Kothari, 2018)
  • Evaluate weakness of the thumb both abduction and opposition; thenar atrophy (atrophy of the palm muscles at the base of the thumb) may help rule-in CTS, but should not be used to rule-out CTS (Graham et al., 2016)

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Common Diagnostic Tests (Durham & VanRavenstein, 2017)

No test should be used alone to diagnose CTS. A combination of physical exam, diagnostic questionnaires and electrodiagnostic studies provide better accuracy to rule-in or rule-out CTS.

Tests Used to Aid in the Diagnosis of Carpal Tunnel Syndrome
Test Maneuver Positive Test
Phalen’s Hold wrist in a fixed flexion position for 1 minute Development of or increase in paresthesia along median nerve
Tinel’s test Tapping over the median nerve, proximal to or on top of the carpal tunnel Tingling feeling or electrical shocks along the median nerve
Two-point discrimination Ability to distinguish between two sharp objects at different points >5 mm sensation between points considered abnormal
Manual carpal compression test Apply pressure over the transverse carpal ligament Paresthesia occurs within 30 seconds of applying pressure
Flick Patient reported Waking at night and shaking (flicking) hands to relieve numbness and/or pain
Hand diagram Patient reported Patient draws on diagram of hand where symptoms are located; score based on location relative to median nerve
Thenar atrophy Assess for atrophy of the palm muscles at the base of the thumb on physical exam Loss of bulk to the abductor pollicis brevis muscle (located in the hand between the wrist and the base of the thumb)
Nerve Conduction Studies (NCS) Motor conduction studies of the median nerve; quantifies disease severity and differentiates muscle conditions from neurological disorders Slowed conduction velocities indicates CTS; more severe compression may result in motor or sensory nerve action potential amplitude; mild CTS may not show any conduction abnormalities
Electromyography (EMG) Assess for changes in the muscles innervated by the median nerve; most useful to exclude other conditions such as polyneuropathy, plexopathy, and radiculopathy (pinched nerve) Active denervation (fibrillation potentials, positive sharp waves) or chronic changes that may indicate denervation and reinnervation (changes in motor unit action potential amplitudes, durations, and recruitment)
Magnetic Resonance Imaging (MRI) Use only in rare cases to rule out a mass or lesion; MRI should not be used routinely for CTS diagnosis. Detects abnormalities of the median nerve, flexor tendons, vascular structures, and transverse carpal ligament

Differential Diagnosis (Kothari, 2018a)

Several neurologic, musculoskeletal, and vascular conditions can mimic CTS such as:

  • Cervical spine disorders
  • Brachial plexopathy
  • Proximal lesions of the median nerve
  • Various types of polyneuropathy

Less frequently, the following may present with symptoms similar to CTS:

  • Central nervous system lesions
  • Motor neuron disease
  • Compartment syndrome in the forearm or hand
  • Fibromyalgia
  • Osteoarthritis
  • Inflammatory arthropathy of the small hand joints
  • Raynaud phenomenon

Grading

Patient management is based on severity of CTS symptoms and degree of injury as found on electrodiagnostic studies.

Grading Severity of CTS (Kothari, 2018b)
  Clinical Grading Electrodiagnostic Grading
Mild
  • Numbness, tingling, or discomfort in the median nerve.
  • No sensory loss or weakness, no sleep disruption, no difficulty with hand function or interference with activities of daily living (ADLs).
  • Prolonged (relative or absolute) sensory latencies with normal motor studies.
  • No evidence of axon loss.
Moderate
  • Sensory loss in the median distribution or symptoms at night that disrupt sleep.
  • Symptoms may interfere slightly with hand function, but the patient is able to perform all ADLs.
  • Abnormal median sensory latencies, and relative or absolute prolongation of median motor distal latency.
  • No evidence of axon loss.
Severe
  • Weakness in the median distribution or if symptoms are disabling and prevent the patient from one or two ADLs, or if nocturnal symptoms routinely disrupt sleep.
  • Evidence of axon loss defined by one of the following:
    • Absent or low-amplitude sensory nerve action potential (SNAP) or mixed nerve action potential
    • Low amplitude or absent thenar compound muscle action potential (CMAP)
    • Needle electromyography with fibrillation potentials or motor unit potential changes (large amplitude, long-duration motor unit potentials, or excessive polyphasics)

Nonsurgical Management (Durham & VanRavenstein, 2017; Graham et al., 2016)

Nonsurgical treatment should be used for patients with mild CTS who have not had electrodiagnostic studies. A combination of therapies (splinting along with glucocorticoid injections, oral glucocorticoids, or other nonsurgical interventions) may be more effective than any single treatment. Improvement may take up to 6 months.

  • Lifestyle modifications
    • Avoid repetitive motions
    • Take frequent breaks
    • Use ergonomic equipment
    • Alternate job functions
  • Wrist splinting
    • Wrist splinting in neutral position and 0° extension with custom-fit wrist splints for night-time use and as needed for daytime symptoms
    • Minimum of 6 to 8 weeks; if symptoms persist after one month, continue splinting for another 1 to 2 months and add another therapy (oral or injection corticosteroid)
  • Corticosteroid injections – should be the next option (before oral corticosteroids) if splinting is unsuccessful 
    • Reduces tissue inflammation
    • May provide relief for up to a year
    • Single injection of methylprednisolone, with 40 mg as the recommended dose
    • Contraindicated with Thenar muscle weakness and/or atrophy or advanced sensory loss
    • Multiple injections are not recommended; limit frequency of injections for CTS to no more than once every six months per wrist; for recurrent symptoms after two injections, consider other nonsurgical treatments or surgical evaluation
    • Risks include: worsening of median nerve compression, accidental injection into the median or ulnar nerve, and digital flexor tendon rupture
  • Oral corticosteroids
    • Provide short-term relief
    • Use in patients who decline injection therapy
    • Prednisone 20 mg daily for 10 to 14 days (Kothari, 2018b)
    • Do not use for more than 4 weeks due to side effects
  • Exercises
    • Refer to physical and occupational therapists with certification in hand therapy
      • Nerve and tendon gliding – may restore normal movement of the median nerve
      • Carpal bone mobilization – movement of the bones and joints in the wrist
    • Yoga – limited studies show yoga may be beneficial
  • Ultrasound therapy and electrical stimulation
    • Ultrasound promotes soft tissue healing and transdermal absorption of medications; however, evidence is limited
    • Deep, pulsed ultrasound may decrease pain and improve sensory loss, nerve conduction, and strength
    • Effectiveness may depend on duration of therapy
    • Ketoprofen phonophoresis (ultrasound enhanced application of topical drug) may reduce CTS pain
  • Ineffective therapies: nonsteroidal anti-inflammatory drugs (NSAIDs), diuretics, gabapentin, astaxanthin capsules, pyridoxine, and electrical, magnetic, and laser therapy have not proven beneficial for the treatment of CTS.

Factors associated with failure of nonsurgical therapy:

  • Long duration of symptoms
  • Age > 50 years
  • Constant paresthesia
  • Impaired two-point discrimination (>6 mm)
  • Positive Phalen sign < 30 seconds
  • Prolonged motor and sensory latencies on electrodiagnostic testing

Surgical Management (Kothari, 2017; Graham et al., 2016)

  • Surgical Decompression
    • For patients with CTS whose electrodiagnostic tests show severe and ongoing median nerve injury, characterized by significant axonal degeneration on nerve conduction studies, or active and chronic denervation on needle electromyography, surgical decompression is recommended, unless the cause is temporary such as pregnancy.
    • Surgical release of the transverse carpal ligament is typically performed.
      • Simultaneous bilateral release may be performed.
      • Staged endoscopic carpal tunnel release may be performed based on patient and surgeon preference.
    • Studies support there is a greater treatment benefit of surgery over nonsurgical treatment at 6 and 12 months.
    • Performed in outpatient setting under local anesthesia by a specialist
      • Local anesthesia is recommended over intravenous regional anesthesia as it may offer longer pain relief.
      • Buffered lidocaine is recommended over plain lidocaine for local anesthesia as it could result in less injection pain.
    • Prophylactic antibiotics given prior to carpal tunnel release are not recommended as there is no evidence of a reduction in postoperative surgical site infections.
    • Studies support there is no benefit to routine postoperative immobilization following carpal tunnel release.

References:

Durham, C.O. & VanRavenstein, K. (2017). It’s all in the wrist: diagnosis and management of carpal tunnel syndrome. Orthopaedic Nursing. 36(5): 323 – 327. doi: 10.1097/NOR.0000000000000390.

Graham, B., Peljovich, A.E., Afra, R., Cho, M.S., Gray, R., Stephenson, J. … Sevarino, K. (2016). The American Academy of Orthopaedic Surgeons Evidence-Based Clinical Practice Guideline on: Management of Carpal Tunnel Syndrome. The Journal of Bone & Joint Surgery. 98(20): 1750 – 1754. doi: 10.2106/JBJS.16.00719

Kothari, M.J. (2017). Carpal tunnel syndrome: Etiology and epidemiology. UpToDate. Retrieved from https://www.uptodate.com/contents/carpal-tunnel-syndrome-etiology-and-epidemiology

Kothari, M.J. (2018a). Carpal tunnel syndrome: Clinical manifestations and diagnosis. UpToDate. Retrieved from https://www.uptodate.com/contents/carpal-tunnel-syndrome-clinical-manifestations-and-diagnosis Kothari,

M.J. (2018b). Carpal tunnel syndrome: Treatment and prognosis. UpToDate. Retrieved from https://www.uptodate.com/contents/carpal-tunnel-syndrome-treatment-and-prognosis