Ads 468x60px



Friday, August 21, 2009

Carpal Tunnel Syndrome

Carpal Tunnel Syndrome
• The median nerve, flexor digitorum profundus, flexor digitorum superficialis, and flexor pollicis longus are located in the carpal tunnel.
• Area bound by the carpal bones and the transverse carpal ligament
• Compression of the median nerve causes symptoms.
• Occupational/overuse syndromes-high impact, repetitive motion
• Trauma
• Pregnancy, birth control pills
• Granulomatous disease: tuberculosis, sarcoidosis
• Mass lesions with median nerve compression
• Osteophytes
• Amyloid
• Multiple myeloma
• Rheumatoid arthritis
• Endocrine disorders: hypothyroidism, diabetes mellitus, acromegaly
• Chronic hemodialysis
• Idiopathic
Pediatric Considerations
• Idiopathic cause rare in children; most cases have correctable cause including:
o Trauma
o Mucolipidosis
o Hamartoma of the median nerve
o Anomalous flexor digitorum superficialis (FDS)
o Hemophilia with hematoma
Signs and Symptoms
• Numbness/paresthesias in median nerve distribution:
o Thumb, index, middle, and radial aspect of ring finger
• Pain:
o Location: wrist or hand, sometimes radiating to elbow, forearm, or shoulder
o Often worse at night-relieved by shaking out the hand
o Exacerbated by repetitive wrist movement and by activities in which the wrist is flexed (e.g., driving)
Physical Exam
• Weakness of the abductor pollicis brevis and opponens muscles:
o Innervated by the recurrent branch of the median nerve
o Patient may complain of dropping things or having decreased fine motor control.
o Sensitivity of 29%; specificity of 80%, on average
• Loss of two-point discrimination:
o Late finding, highly specific
o Sensitivity of 24%; specificity of 94%
• Atrophy of thenar muscles:
o Late finding, highly specific
o Sensitivity of 18%; specificity of 94%
Essential Workup
• History of characteristic nocturnal pain and paresthesias in the median nerve distribution.
• Muscle weakness and thenar wasting are later findings.
• Provocative testing:
o Phalen test:
 Wrist flexion for 60 seconds produces numbness or tingling in the median nerve distribution.
 Sensitivity of 68%; specificity of 73%
o Tinel sign:
 Gentle tapping over the median nerve at wrist produces tingling in the fingers in the median nerve distribution.
 Sensitivity of 50%; specificity of 77%
o Carpal compression test:
 Thumb pressure applied over the proximal carpal ligament produces tingling in the fingers in the median nerve distribution.
 Sensitivity of 64%; specificity of 83%
o Tourniquet test:
 Blood pressure (BP) cuff inflated to just above the patient's systolic blood pressure for 2 minutes produces paresthesias in the median nerve distribution.
 Sensitivity of 59%; specificity of 61%
• Not indicated in most cases
• Thyroid function studies; rheumatoid factor and immune panel if indicated by history and physical exam
• Wrist radiograph if trauma or degenerative arthritis suspected
• CT in select cases:
o May show encroachment of carpal tunnel
• MRI displays the soft tissues well but may not be justified in ED owing to time and cost:
o Findings: palmar bowing of transcarpal ligament, flattened median nerve, median nerve or synovial swelling, fluid in carpal tunnel, signal abnormality of median nerve
• Ultrasound can be diagnostic:
o Findings: median nerve swelling at proximal canal, median nerve flattening at distal canal, bowing of transcarpal ligament
Diagnostic Procedures/Surgery
Nerve conduction studies and electromyography are criterion standard tests.

Differential Diagnosis
• Cervical nerve root compression:
o Origin of median nerve is at the sixth and seventh cervical roots.
o Symptoms are aggravated by erect posture and neck movement.
• Hand-arm vibration syndrome:
o Characterized by Raynaud, numbness and tingling in ulnar and median nerve distributions when exposed to cold or vibration, weakened grip, and upper extremity myalgias
o Associated with prolonged exposure to vibration
• Thoracic outlet obstruction
• Osteoarthritis of the first carpometacarpal joint
• Brachial plexitis
• Generalized neuropathy
• Syringomyelia
Initial Stabilization
None necessary
ED Treatment
• Splint wrist in neutral position (0 degrees).
• Aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs)
• Avoidance of repetitive wrist movement
• Wrist splint to be worn at night until follow-up
• Apply heat to involved wrists heating pad, hot water bottle, low-level heat wraps
• Referral to occupational medicine for ergometric testing if caused by repetitive motion, and tendon gliding or nerve gliding exercises
• May need referral to a hand surgeon for consideration of surgical release of transverse carpal ligament using either open or endoscopic technique
Medication (Drugs)
• NSAIDs (there are many choices; a few are listed below):
o Ibuprofen: 600 mg (peds: 5-10 mg/kg) PO q6h
o Ketorolac: 30 mg IV or IM q6h or 10 mg PO q4h-q6h
o Diclofenac: 50 mg PO b.i.d. or t.i.d.
o Piroxicam: 20 mg PO daily
• Local corticosteroid injection provides transient relief in two thirds of patients (many different regimens):
o Hydrocortisone: 25-100 mg
o Methylprednisolone: 40 mg
o Prednisolone suspension: 20-40 mg
o Triamcinolone: 20 mg

Discharge Criteria
Discharge to home with appropriate referral to either patient's primary care physician or directly to a specialist in occupational medicine or hand surgery.

1. Al-Qattan MM, Thompson HG, Clarke HM. Carpal tunnel syndrome in children and adolescents with no history of trauma. J Hand Surg. 1996;21B(1):108-111.
2. Kanaan N, Sawaya RA. Carpal tunnel syndrome: modern diagnostic and management techniques. Br J Gen Pract. 2001;51:311-314.
3. MacDermid JC, Wessel J. Clinical diagnosis of carpal tunnel syndrome: a systematic review. J Hand Ther. 2004;17(2):309-319.
4. Michlovitz SL. Conservative interventions for carpal tunnel syndrome. J Orthop Sports Phys Ther. 2004;34(10):589-600.
5. O'Gradaigh D, Merry P. Corticosteroid injection for the treatment of carpal tunnel syndrome. Ann Rheum Dis. 2000;59:918-919.
6. Sternbach G. The carpal tunnel syndrome. J Emerg Med. 1999;17:519-523.
7. Whitley JM, McDonnell DE. Carpal tunnel syndrome. A guide to prompt intervention. Postgrad Med. 1995;97(1):89-96.

No comments: