Evaluation of Left Wrist for Carpal Tunnel Syndrome
Begin with clinical assessment combined with electrophysiologic studies (nerve conduction studies/EMG), as this is the primary diagnostic approach recommended by the American College of Radiology for carpal tunnel syndrome. 1, 2
Initial Clinical Evaluation
Key Clinical Features to Assess
- Pain and paresthesias in the median nerve distribution (palmar aspect of thumb, index and middle fingers, and radial half of ring finger) 3
- Flick sign (patient shakes hand to relieve symptoms) 3
- Phalen maneuver (wrist flexion for 60 seconds reproducing symptoms) 3
- Median nerve compression test (direct pressure over carpal tunnel) 3
- Hypalgesia and weak thumb abduction are more predictive of abnormal nerve conduction studies than Tinel's sign or Phalen's maneuver 4
Critical Pitfall to Avoid
If bilateral symptoms are present, consider systemic conditions or cardiac amyloidosis, particularly if there is no history of rheumatoid arthritis or trauma 1, 5
Diagnostic Testing Algorithm
Step 1: Electrophysiologic Studies
- Obtain nerve conduction studies/EMG to confirm diagnosis and determine severity 1, 2, 3
- This is essential if surgical decompression is being considered, as it determines surgical prognosis 3
- Electrodiagnostic testing helps differentiate carpal tunnel syndrome from cervical radiculopathy when clinical presentation is unclear 6
Step 2: Imaging (Selected Circumstances Only)
Ultrasound is the first-line imaging modality when imaging is needed, as it is more cost-effective and widely available than MRI 1
Indications for Ultrasound:
- Clinical symptoms with unclear diagnosis after electrophysiologic studies 2
- To identify anatomic variants (bifid median nerve, persistent median artery) 1
- To detect space-occupying lesions or tenosynovitis 1
- Primary diagnostic criterion: median nerve cross-sectional area ≥10 mm² at the carpal tunnel inlet 1
Ultrasound Technique:
- Patient sitting with hand resting on thigh or examination table 1
- High-frequency transducers (≥10 MHz) 1
- Volar transverse and longitudinal scans at carpal tunnel 1
- Dynamic examination with active finger flexion/extension 1
When to Consider MRI:
- MRI is typically NOT indicated for routine evaluation 1, 2
- Reserve for selected circumstances when ultrasound is inconclusive or detailed soft-tissue characterization is required 1
- MRI can detect carpal tunnel syndrome with high accuracy and identify associated tendon pathology 1
Imaging NOT Appropriate:
- Plain radiographs (unless bony abnormality or arthritis suspected) 1
- CT, CT arthrography, bone scan (not appropriate for routine carpal tunnel syndrome evaluation) 1
Treatment Decision Algorithm
Mild to Moderate Carpal Tunnel Syndrome (Conservative Management First):
- Nighttime wrist splinting in neutral position 2, 4, 3
- Local corticosteroid injection can provide relief for more than one month and delay surgery at one year 3
- Oral corticosteroids effective for short-term management (2-4 weeks) 4
- Physical therapy, therapeutic ultrasound, and yoga are options 3
Avoid Ineffective Treatments:
- NSAIDs, pyridoxine (vitamin B6), and diuretics are no more effective than placebo 4, 3
- Discontinue acetaminophen and ibuprofen as they do not address nerve compression 2
Indications for Surgical Decompression:
- Severe carpal tunnel syndrome on electrodiagnostic studies 2, 3
- Symptoms refractory to conservative measures after 4-6 months 2, 3
- Surgical decompression is the most effective treatment for moderate to severe cases 2
- Open and endoscopic techniques are equally effective, but endoscopic allows return to work approximately one week earlier 2, 3
Special Consideration:
In pregnant women, treat conservatively as spontaneous postpartum resolution is common 4