Carpal tunnel syndrome - clinical fact sheet and MCQ

Overview 

Carpal tunnel syndrome (CTS) is the most common compressive neuropathy of the upper limb, affecting up to 14% of the adult population. It results from compression of the median nerve as it traverses the carpal tunnel, a confined fibro-osseous space at the wrist bordered by the carpal bones dorsally and the transverse carpal ligament volarly. The syndrome predominantly affects women aged over 40 and is a leading cause of workplace disability. Up to 70% of people can have bilateral symptoms.

The primary impact of CTS stems from nocturnal paraesthesia and sensory disruption in the digits on the radial side of the hand, often associated with functional limitations in grip strength, manual dexterity, and sleep disturbance. If untreated, CTS may progress to persistent numbness, thenar atrophy, and irreversible nerve dysfunction.

Aetiology and risk factors

While CTS is idiopathic in most cases, several contributing factors are recognised:

• anatomical: congenitally small carpal tunnel, ganglion cysts, tumours, trauma (eg distal radius fracture), or anomalous musculature

• systemic: diabetes, hypothyroidism, obesity, rheumatoid arthritis, renal failure, and amyloidosis

• physiological: pregnancy-related oedema, particularly in the third trimester

• occupational: high repetition, forceful grip, and exposure to vibratory tools. Despite common concerns, high keyboard use has not been definitively linked to increased risk​

Diagnosis of carpal tunnel syndrome

1. Clinical diagnosis

CTS diagnosis is primarily clinical, supported by history, physical examination, and where necessary, confirmatory tests. 

Symptoms:

• numbness and tingling (paresthesia) in thumb, index, middle finger and radial border of ring finger

• clumsiness/loss of dexterity

• grip and pinch weakness (chronic compression)

• pain and paresthesia awaken patient at night

• daytime paresthesia can be provoked by activities involving prolonged wrist flexion or extension

• may describe shaking hand to alleviate symptoms

Signs:

• thenar muscle wasting

• positive provocative tests (see below)

The CTS-6 clinical diagnostic tool may be used as a first-line approach, given its high diagnostic accuracy. 

A score of ≥12 points is typically used as a diagnostic threshold indicating a high probability of CTS.

Provocative tests include:

• Phalen’s test: reproduction of symptoms with wrist flexion for 60 seconds

(image credit: Wikipedia, https://en.wikipedia.org/wiki/Phalen_maneuver)

• Tinel’s sign: tingling upon percussion over the carpal tunnel

(image credit: Stanford Medicine, https://stanfordmedicine25.stanford.edu/the25/carpaltunnel.html)

• Durkan’s compression test: manual pressure over the carpal tunnel for 30 seconds

(image credit: Stanford Medicine, https://stanfordmedicine25.stanford.edu/the25/carpaltunnel.html)

The Durkan test has the highest sensitivity (up to 89%) and specificity (up to 96%) among bedside tests​.

2. Additional diagnostic testing

Electrodiagnostic studies (nerve conduction studies with or without electromyography) are not routinely necessary but are useful:

• when the diagnosis is unclear

• when symptoms are atypical

• prior to surgery

A distal motor latency >4.5 ms and sensory latency >3.5 ms are diagnostic indicators. However, early CTS can yield normal results, and asymptomatic individuals may have abnormal findings.

Imaging (MRI, ultrasonography) and upper limb neurodynamic testing are not recommended for routine diagnosis due to limited evidence of clinical benefit​.

3. Differential diagnoses include:

• cervical radiculopathy, especially C6 (neck pain, dermatomal distribution, weakness across multiple myotomes)

• pronator teres syndrome (forearm pain, no nocturnal symptoms, normal Tinel’s at wrist)

• thoracic outlet syndrome (symptoms worsened by arm elevation, affects whole hand)

• ulnar nerve entrapment at the elbow or wrist (numbness in ring/little fingers, hypothenar muscle involvement)

• complex regional pain syndrome (disproportionate pain, skin changes, allodynia, often post-injury)

4. Red flags for carpal tunnel syndrome

• Constant pain (unusual in CTS; consider complex regional pain syndrome)

• Proximal radiation (possible cervical radiculopathy, not isolated median neuropathy)

• Rapid progression (suggests aggressive pathology like mass, tumour, or infection)

• Motor-only symptoms (may indicate proximal nerve lesion or anterior interosseous syndrome)

• Symptoms inconsistent with the median nerve distribution (may indicate double crush (compression at two or more locations along the course of a peripheral nerve) or ulnar neuropathy if symptoms along ulnar nerve distribution)

Management of carpal tunnel syndrome

Management should be tailored to symptom severity, chronicity, functional impairment, and patient preference.

1. Non-operative management

• Wrist splinting: night-time splinting in a neutral position is first-line therapy for mild-to-moderate CTS

• Corticosteroid injection: provides short-term relief (typically <10 weeks) but lacks long-term benefit and should not be relied upon for sustained symptom control​

• Platelet-rich plasma (PRP): strong evidence advises against PRP (leukocyte-rich or -poor) due to lack of efficacy​

• Other modalities: acupressure, ultrasound, diuretics, anticonvulsants, magnet therapy, laser therapy, exercise, and nutritional supplements have not shown long-term benefit and are not recommended for routine use​

2. Referral for surgical management

Referral to a hand surgeon is indicated for moderate-to-severe symptoms refractory to non-operative treatment, motor weakness, or persistent numbness.

• Both open and endoscopic carpal tunnel release (CTR) yield comparable outcomes; choice depends on surgeon expertise and patient preference​

• Local anaesthetic alone is strongly supported for CTR procedures and reduces postoperative morbidity​

If CTS is pregnancy-related, avoid surgery if possible as symptoms are likely to self-resolve after birth. 

3. Postoperative care

• Immobilisation is not recommended. Avoid slings, splints, or braces following CTR, as these delay functional recovery​

• Routine referral for therapy is not advised unless specific functional concerns persist​

• Encourage finger and wrist range of motion

• Pain management with NSAIDs and/or paracetamol are first-line. Tramadol may be used judiciously in selected patients, with avoidance of stronger opioids where possible​

• Prophylactic perioperative antibiotics are not routinely indicated​.

• GPs may be asked to perform a post-operative wound review at 5-7 days post surgery. Sutures can usually be removed at that time.

4. Prognosis and follow-up

Most patients experience substantial symptom relief following surgical decompression. Sensory recovery may take weeks to months; motor deficits and thenar atrophy may be only partially reversible. Delays in treatment may result in permanent nerve dysfunction. Recurrence is rare but may occur due to incomplete release or scar tissue formation.

References

American Academy of Orthopaedic Surgeons. Management of Carpal Tunnel Syndrome: Evidence-Based Clinical Practice Guideline. 2024.

Cranford CS, Ho JY, Kalainov DM, Hartigan BJ. Carpal Tunnel Syndrome. J Am Acad Orthop Surg. 2007;15(9):537-548.

Therapeutic Guidelines. Carpal tunnel syndrome. 2024. (last accessed April 2025).

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