Carpal Tunnel Syndrome

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Aetiology

• Pregnancy
• Obesity
• Diabetes Mellitus
• Hypothyroidism
• Acute fluid retention
• Connective tissue diseases
• Rheumatoid arthritis
• Local abnormalities/lesions involving the wrist, including previous fractures

Differential Diagnosis

• Cervical radicular pain (C6 or C7): Neck pain, positive Spurlings test
• First Carpometacarpal Joint Osteoarthritis : Painful thumb motion, positive grind test, radiographic findings
• De Quervain Tendinopathy: Tenderness distal radial styloid
• Polyneuropathy: History of diabetes mellitus, bilateral, lower extremity involvement.
• Thoracic Outlet Syndrome: ulnar sided symptoms, positive EAST and ULTT.
• Pronator teres syndrome (median nerve compression at the elbow): Forearm pain; sensory loss over the thenar eminence; weakness with thumb flexion, wrist extension, and forearm pronation
• Ulnar neuropathy: Paresthesias of the ring and little fingers, positive Tinel sign and compression tests at the elbow or wrist (Guyon canal)
• Radial neuropathy
• Raynaud syndrome:Symptoms related to cold exposure, typical color changes
• Vibration white finger:Use of vibratory hand power tools, symptoms of Raynaud phenomenon
• Wrist osteoarthritis: painful wrist motion, radiographic findings
• Inflammatory arthropathy
• Peripheral nerve tumour
• Multiple sclerosis
• Amyotrophic lateral sclerosis
• Acute compression syndromes (eg, Saturday night palsy)

Assessment

• Symptoms are often variable but classically include pain or paraesthesia in the median nerve distribution.
• Neurological examination
• Provocative tests

The value of history and physical examination features with EMG as the reference standard.

Test Name	LR+	LR-	Sens	Spec	Kappa
Flick sign	21	0.1	93%	96%
Closed fist sign	7.3	0.4	61%	92%
Hypalgesia	3.1	0.7	39%	88%
Square wrist sign	2.7	0.6	53%	80%
Classic or probable Katz hand diagram	2.4	0.5	64%	73%
Weak thumb adduction	1.8	0.5	65%	65%
Thenar atrophy	1.6	0.9	16%	90%
Abnormal vibration	1.6	0.8	36%	77%
Abnormal monofilament findings	1.5	0.7	59%	59%
Bilateral symptoms	1.4	0.7	61%	58%
Tinel sign	1.4	0.8	36%	75%
Phalen sign	1.3	0.7	57%	58%
Age > 40 years	1.3	0.5	80%	41%
Nocturnal paresthesias	1.2	0.7	70%	43%
2-point discrimination	1.2	1.0	20%	83%

Investigations

Not normally required, but can include nerve conduction studies or diagnostic ultrasound. These modalities cannot exclude the condition.

Treatment

Conservative treatment for mild and intermittent symptoms, or symptoms that are likely to resolve soon such as during pregnancy.

Activity Modification

Corticosteroid injection

See Carpal Tunnel Injection article.

Splinting and Hand Therapy

Hand therapists can teach graded exercises and provide custom thermoplastic or off the shelf splints.

Surgery (Carpal tunnel release or decompression)

Consider conservative therapy first until severe pain or marked neurological signs. Access to surgery is variable across New Zealand. Surgery may not result in complete recovery of any neurological deficit but may prevent progression.