Editing Carpal tunnel syndrome (section)

== Diagnosis ==
There is no consensus reference standard for the diagnosis of carpal tunnel syndrome. A combination of characteristic symptoms (how it feels) and signs (what the clinician finds on exam) are associated with a high probability of CTS without [[electrophysiological]] testing.

[[Electrodiagnostic testing]] including [[electromyography]], and [[nerve conduction studies]]  can objectively measure and verify median neuropathy.<ref>{{Citation | vauthors = Rosario NB, De Jesus O |title=Electrodiagnostic Evaluation Of Carpal Tunnel Syndrome |date=2022 |url=http://www.ncbi.nlm.nih.gov/books/NBK562235/ |work=StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=32965906 |access-date=2022-07-28 }}</ref>

Ultrasound can image and measure the cross sectional diameter of the median nerve, which has some correlation with CTS. The role of ultrasound in diagnosis—just as for electrodiagnostic testing—is a matter of debate. EDX cannot fully exclude the diagnosis of CTS due to the lack of sensitivity.{{citation needed|date=July 2024}}

The role of confirmatory electrodiagnostic testing is debated.<ref name="Padua2016" /> The goal of electrodiagnostic testing is to compare the speed of conduction in the median nerve with conduction in other nerves supplying the hand. When the median nerve is compressed, it will conduct more slowly than normal and more slowly than other nerves. [[Nerve compression syndrome|Nerve compression]] results in damage to the myelin sheath and manifests as delayed latencies and slowed conduction velocities.<ref name="uptodate.com" /> Electrodiagnosis rests upon demonstrating impaired median nerve conduction across the carpal tunnel in context of normal conduction elsewhere.

It is often stated that normal electrodiagnostic studies do not preclude the diagnosis of carpal tunnel syndrome. The rationale for this is that a threshold of neuropathy must be reached before study results become abnormal and also that threshold values for abnormality vary.<ref name="Graham consensus">{{cite journal | vauthors = Graham B, Regehr G, Naglie G, Wright JG | title = Development and validation of diagnostic criteria for carpal tunnel syndrome | journal = The Journal of Hand Surgery | volume = 31 | issue = 6 | pages = 919–924 | year = 2006 | doi = 10.1016/j.jhsa.2006.03.005 | pmid = 16886290 }}</ref> Others contend that idiopathic median neuropathy at the carpal tunnel with normal electrodiagnostic tests would represent very, very mild neuropathy that would be best managed as a normal median nerve. Even more important, notable symptoms with mild disease is strongly associated with unhelpful thoughts and symptoms of worry and despair. Notable CTS should remind clinicians to always consider the whole person, including their mindset and circumstances, in strategies to help people get and stay healthy.<ref>{{cite journal | doi=10.1001/jama.2017.4545 | title=Changing Mindsets to Enhance Treatment Effectiveness | date=2017 | last1=Crum | first1=Alia | last2=Zuckerman | first2=Barry | journal=JAMA | volume=317 | issue=20 | pages=2063–2064 | pmid=28418538 | pmc=7608684 }}</ref>

A joint report published by the [[American Association of Neuromuscular & Electrodiagnostic Medicine]] (AANEM), the American Academy of Physical Medicine and Rehabilitation (AAPM&R), and the American Academy of Neurology defines practice parameters, standards, and guidelines for EDX studies of CTS based on an extensive critical literature review. This joint review concluded median and sensory nerve conduction studies are valid and reproducible in a clinical laboratory setting and a clinical diagnosis of CTS can be made with a sensitivity greater than 85% and specificity greater than 95%. The AANEM has issued evidence-based practice guidelines for the diagnosis of carpal tunnel syndrome, both by electrodiagnostic studies and by neuromuscular ultrasound.<ref>{{cite web |url=https://www.aanem.org/docs/default-source/documents/nmus-for-dx-of-cts_reaffirmed.pdf |title=Evidence-Based Guideline [reaffirmed]: Neuromuscular Ultrasound for the Diagnosis of Carpal Tunnel Syndrome |vauthors=Cartwright M, et al |publisher=American Association of Neuromuscular and Electrodiagnostic Medicine |date=September 2017}}</ref>

=== Imaging ===
The role of [[magnetic resonance imaging|MRI]] or [[medical ultrasonography|ultrasound imaging]] in the diagnosis of CTS is unclear.<ref name="Wilder-Smith_2006">{{cite journal | vauthors = Wilder-Smith EP, Seet RC, Lim EC | title = Diagnosing carpal tunnel syndrome--clinical criteria and ancillary tests | journal = Nature Clinical Practice. Neurology | volume = 2 | issue = 7 | pages = 366–374 | date = July 2006 | pmid = 16932587 | doi = 10.1038/ncpneuro0216 | s2cid = 22566215 }}</ref><ref name=Bland_2005>{{cite journal | vauthors = Bland JD | title = Carpal tunnel syndrome | journal = Current Opinion in Neurology | volume = 18 | issue = 5 | pages = 581–585 | date = October 2005 | pmid = 16155444 | doi = 10.1097/01.wco.0000173142.58068.5a | s2cid = 945614 }}</ref><ref name=Jarvik_2004>{{cite journal | vauthors = Jarvik JG, Yuen E, Kliot M | title = Diagnosis of carpal tunnel syndrome: electrodiagnostic and MR imaging evaluation | journal = Neuroimaging Clinics of North America | volume = 14 | issue = 1 | pages = 93–102, viii | date = February 2004 | pmid = 15177259 | doi = 10.1016/j.nic.2004.02.002 }}</ref> Their routine use is not recommended.<ref name=AAOS2016 /> Morphological MRI has high sensitivity but low specificity for CTS. High signal intensity may suggest accumulation of axonal transportation, myelin sheath degeneration or oedema.<ref name="Carpal Tunnel Syndrome: Symptoms, C"/> However, more recent quantitative MRI techniques which derive repeatable, reliable and objective biomarkers from nerves and skeletal muscle may have utility, including diffusion-weighted (typically diffusion tensor) MRI which has demonstrable normal values and aberrations in carpal tunnel syndrome.<ref>{{cite journal | vauthors = Rojoa D, Raheman F, Rassam J, Wade RG | title = Meta-analysis of the normal diffusion tensor imaging values of the median nerve and how they change in carpal tunnel syndrome | journal = Scientific Reports | volume = 11 | issue = 1 | pages = 20935 | date = October 2021 | pmid = 34686721 | pmc = 8536657 | doi = 10.1038/s41598-021-00353-z | bibcode = 2021NatSR..1120935R }}</ref>

=== Differential diagnosis ===
[[Cervical radiculopathy]] can also cause paresthesia abnormal sensibility in the hands and wrist.<ref name="Padua2016" /> The distribution usually follows the nerve root, and the paresthesia may be provoked by neck movement.<ref name="Padua2016" /> Electromyography and imaging of the cervical spine can help to differentiate cervical radiculopathy from carpal tunnel syndrome if the diagnosis is unclear.<ref name="Padua2016" /> Carpal tunnel syndrome is sometimes applied as a label to anyone with pain, numbness, swelling, or burning in the radial side of the hands or wrists. When pain is the primary symptom, carpal tunnel syndrome is unlikely to be the source of the symptoms.<ref name="Graham 2587–2593">{{cite journal | vauthors = Graham B | title = The value added by electrodiagnostic testing in the diagnosis of carpal tunnel syndrome | journal = The Journal of Bone and Joint Surgery. American Volume | volume = 90 | issue = 12 | pages = 2587–2593 | date = December 2008 | pmid = 19047703 | doi = 10.2106/JBJS.G.01362 }}</ref>

When the symptoms and signs point to atrophy and muscle weakness more than numbness, consider neurodegenerative disorders such as [[Amyotrophic lateral sclerosis|Amyotrophic Lateral Sclerosis]] or [[Charcot–Marie–Tooth disease|Charcot-Marie Tooth]].<ref>{{cite journal | vauthors = Genova A, Dix O, Saefan A, Thakur M, Hassan A | title = Carpal Tunnel Syndrome: A Review of Literature | journal = Cureus | volume = 12 | issue = 3 | pages = e7333 | date = March 2020 | pmid = 32313774 | pmc = 7164699 | doi = 10.7759/cureus.7333 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Masrori P, Van Damme P | title = Amyotrophic lateral sclerosis: a clinical review | journal = European Journal of Neurology | volume = 27 | issue = 10 | pages = 1918–1929 | date = October 2020 | pmid = 32526057 | pmc = 7540334 | doi = 10.1111/ene.14393 }}</ref><ref>{{cite book | vauthors = Nagappa M, Sharma S, Taly AB | chapter = Charcot Marie Tooth |date=2022 | chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK562163/ | title = StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=32965834 |access-date=2022-09-06 }}</ref>