You Make Me All Tingly
Author: Derek Hatfield, MD
Peer-Reviewer: Vincent Giron, DO
Final Editor: Brandon Godfrey, MD, Alex Tomesch, MD, CAQ-SM
A 31 year old obese female presents to the clinic with complaints of numbness and tingling in her hand that has been waking her up at night. Her numbness and tingling is limited to the palmar side of her hands over the first 3 digits. She works as a computer programmer. Her wrist ultrasound is shown below.
Image 1. Case courtesy of Maulik S Patel, Radiopaedia.org, rID: 21715
What physical exam findings are expected?
On exam patients will complain of decreased sensation or paresthesias over the palmar aspect of the thumb, second, third, and radial half of the fourth digit. Motor testing can show weakness with grip strength, pinch, and thumb abduction. You may also notice thenar atrophy in severe cases [1].
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Pearls: Special tests for carpal tunnel syndrome include Tinel Sign, Phalen Test, Reverse Phalen Test, and carpal compression test. Any test is positive for carpal tunnel syndrome if there is a reproduction of symptoms
Image 2: Image from StatPearls courtesy of Rian Kabir, MD. Shared under the creative commons license.
Which imaging modalities can be used?
This is typically a clinical diagnosis but EMG and US can be helpful in establishing a diagnosis if there is diagnostic uncertainty. If there is concern for a space-occupying lesion, MRI can also be performed.
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Pearl: While there is still debate as to the absolute value, an increased cross sectional area of the median nerve can be indicative of carpal tunnel syndrome. <10 mm is considered normal [3].
Image 3. Previous ultrasound showing diameter of median nerve being 19 mm. Case courtesy of Maulik S Patel, Radiopaedia.org, rID: 21715
References
[1] Genova A, Dix O, Saefan A, Thakur M, Hassan A. Carpal Tunnel Syndrome: A Review of Literature. Cureus. 2020 Mar 19;12(3):e7333. doi: 10.7759/cureus.7333. PMID: 32313774; PMCID: PMC7164699.
[2] Luchetti R, Amadio P. Carpal tunnel syndrome. Berlin: Springer-Verlag; 2007. pp. 32–59.
[3] Karadağ YS, Karadağ O, Ciçekli E, et al. Severity of Carpal tunnel syndrome assessed with high frequency ultrasonography. Rheumatol Int. 2010;30(6):761-765. doi:10.1007/s00296-009-1061-x
[4] American Academy of Orthopaedic Surgeons. Management of carpal tunnel syndrome evidence-based clinical practice guideline. [ Apr; 2022 ];https://www.aaos.org/
[5] Wright AR, Atkinson RE. Carpal Tunnel Syndrome: An Update for the Primary Care Physician. Hawaii J Health Soc Welf. 2019 Nov;78(11 Suppl 2):6-10. PMID: 31773104; PMCID: PMC6874691.