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Carpal Tunnel Syndrome

Study guide:

 Definition:

  • ​A peripheral neuropathy resulting from compression of the median nerve as it passes under the flexor retinaculum leading to tingling (parethesia), hypothesia (numbness), or anesthesia along the median nerve distribution.

 

Epidemiology:

  • The most common compressive focal mononeuropathy seen in clinical practice.

 

Causes & Risk Factors:

  •  Repetitive use of the hand:

    • Leading to thickening of the synovial lining of the tendons in the carpal tunnel compression of the median nerve pain, numbness and thenar muscle weakness.

    • ​​ Wrist (Colles) fracture

      • ​​Narrowing the passageway of the median nerves and tendons.

  • Diabetes: which is usually associated with nerve damage as part of the complications. o Female gender.

  • Age most common between 30 to 55.

  • Inflammatory conditions such as rheumatoid arthritis.

  • Pregnancy (especially the third trimester), due to fluid retention è edema formation compression of the median nerve

The median n. supplies the LOAF muscles:

2Lumbricals, Opponens pollicis, Abductor pollicis brevis & Flexor pollicis brevis

 

Pathophysiology:

  • Compression of the median nerve leads to disruption of the venous outflow edema formation local ischemia.

  • Capillaries stop supplying -> the deprived of oxygen -> conduction of signals by the median nerve is stopped.

  • In case this pressure was not relieved:

    • Progressive loss of sensation over the thumb, lateral two fingers and part of the ring finger due to loss of innervation from the digital sensory branches of the median nerve.

    • Atrophy and weakness of the thenar muscles due to loss of innervation from the motor recurrent branch of the median nerve.

Signs & Symptoms:

  • Numbness and tingling:

    • The thumb, index finger, middle finger and the radial side of the ring finger.

  • Pain and paraesthesia on palmer aspect of hands and fingers.

  • Waking up at night (because the pain gets worse).

  • Abductor pollicis brevis weakness

  • Loss of sensation in the lateral palm and thumb, index, middle and lateral half of the 4th finger.

  • Thenar muscles atrophy.

Sensory symptoms happen before motor symptoms!

 

Diagnostic Tests:

  • Physical Examination:

    • Positive Phalen test.

    • Positive Tinel test.

    • Positive manual carpal compression test.

  • Electrodiagnostic testing & nerve conduction studies:

    • Are highly sensitive and specific (the most

      accurate/gold standard).

    • Used to determine the severity of median nerve injury.

    • Mandatory in case of future surgical intervention. ​

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Management:

  • Acute, nonsurgical treatment:

    • The best initial therapy is wrist splint, with NSAIDs.

    • If not controlled Steroid injections is administered.

  • Surgical decompression (under local anesthesia):

    • ​Open technique (open carpal tunnel release):

      • Allows detection of anomalies better than the endoscopy.

    •  Endoscopic technique: Chosen sometimes due to conservation of the palmar fascia, subcutaneous fat, and skin.

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Follow-up:

  • Smooth clothing should be worn with active mobilization of the wrist and fingers.

​

Complications:

  • Incomplete release of the transverse ligament due to surgical error. o Injury to branches of the median nerve.

  •  Injuries to superficial vessels in the region.

  •  Scar formation.

Diagnosis of CTS is mostly based on clinical findings!

References:

  1. ASHWORTH, N. Carpal Tunnel Syndrome: Background, Pathophysiology, Epidemiology. Emedicine.medscape.com. N.p., 2015. Web. 13 Dec. 2015

  2. CURRENT Diagnosis & Treatment in Rheumatology. Imboden, John, David Hellmann, and JohnStone. CURRENT Diagnosis & Treatment In Rheumatology. 2nd ed. McGraw-Hill Education, 2006. Print.

  3. MOORE, K. L., DALLEY, A. F. AND AGUR, A. M. R. Clinically oriented anatomy. 7th ed. Philadelphia: Lippincott Williams & Wilkins, 2013. Print.

  4. WALKER, B. R., COLLEDGE, N. R., RALSTON, S. AND PENMAN, I. D. Davidson's principles and practice of medicine

  5. WERNER, R. A. AND ANDARY, M. Carpal tunnel syndrome: pathophysiology and clinical neurophysiology 113.9 (2002): 1373-1381. Web.

  6. Fischer C. Master the boards.

  7. Longmore J, Longmore J. Oxford handbook of clinical medicine. Oxford: Oxford University Press; 2007.

  8. up to date.

  9. http://www.upngophysiotherapy.com.au/educational-information/carpal-tunnel-syndrome/ (Figure 2)

  10. http://www.eatonhand.com/img/img00015.htm (Figure 3)

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Written By:       Raghad AlSayari

Reviewed By:   Shahad AlDelaijan

                        Halimah AlHifzi

Format Editor: Haifa AlIssa

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