History

Fact Explanation
Numbness and tingling The carpal tunnel is formed by the flexor retinaculum that stretches over the carpal bones. The Median Nerve and the flexor tendons traverse the carpal tunnel. [1] Compression of the Median Nerve within the carpal tunnel disrupts nerve transmission causing a sensation of numbness.Pins and needles of the index and middle fingers is by far the most common presenting symptom. [2] The little finger is almost never involved as it is innervated by the Ulnar Nerve.
Pain in the forearm [2] Usually radiates upwards from the wrist along the medial border of the forearm, this is described as an aching pain and not associated with pins and needles. [2] Neurological features are never found proximal to the wrist, and it present should raise the possibility of a different diagnosis. [3]
Weakness of grip As the compression of the Median Nerve increases there is damage to the axons and signs of nerve damage begin to appear. [2] There is often a weakness of fine dexterity of the hand due to weakness of the abductor policis brevis muscle, therefore actions such as picking up a needle, sewing and knitting become difficult. [3,4] Evidence of symptoms is seen more prominently in the dominant hand though fifty percent of patients will exhibit bilateral symptoms. [3]
Exacerbation of symptoms at night [1] Characteristically, attacks of symptoms are nocturnal. [2,3] Though the reason for this remains unexplained, the presentation is so typical that it may even be considered pathognomonic. [2]
Loss of motor function [1] This will occur at a late stage in the disease with continued severe compression of the Median Nerve. Presents as weakness and paralysis of the muscles of the thenar eminence and the lateral two lumbricals. [2]
Improvement of symptoms with shaking (Flick Sign) [6] Patients often say that symptoms improve when the hand is shaken vigorously or when held in a downward facing position. [6] Patients may also complain that they feel as if their hands are swollen but on examination there is no objective swelling. [7]
History of diabetes [8] Carpal tunnel syndrome is common among patients with type I or II diabetes, especially among those with diabetic poly neuropathy. [8]
Associated conditions Diabetes, hypothyroidism, rheumatoid arthritis, osteoarthritis, amyloidosis, obesity, and pregnancy are all associated with an increased risk of carpal tunnel syndrome. [9]
References
  1. SINNATAMBY CHUMMY S ed. Last's Anatomy Regional and Applied. Eleventh Edition. Churchill Livingstone. 2006.
  2. BROWSE Norman L, BLACK John, BURNAND Kevin G, THOMAS William EG. Browse's Introduction to the Symptoms and Signs of Surgical Disease. Fourth Edition. Hodder and Arnold. 2005.
  3. MCCLAIN Alan ed. Hamilton Bailey's Demonstrations of Physical Signs in Clinical Surgery. Sixteenth Edition. John Wright and Sons Ltd. 1984.
  4. RUSSELL RCG, WILLIAMS Norman S, BULSTRODE Christopher JK ed. Bailey and Love's Short Practice of Surgery. Twenty third edition. Arnold. 2000.
  5. Clinical Practice Guidelines on Diagnosis of Carpal Tunnel Syndrome. American Association of Orthopedic Surgeons. May 2007. [viewed 11 April 2014] Available from: http://www.aaos.org/Research/guidelines/CTS_guideline.pdf
  6. LeBLANC Kim Edward, CESTIA Wayne. Carpal Tunnel Syndrome. Am Fam Physician. 2011 Apr 15;83(8):952-958. [viewed 11 April 2014]. Available from: http://www.aafp.org/afp/2011/0415/p952.html
  7. PERKINS Bruce A et al. Carpal Tunnel Syndrome in Patients With Diabetic Polyneuropathy. Diabetes Care March 2002 vol. 25 no. 3 565-569. [viewed 11 April 2014]. Available from: doi: 10.2337/diacare.25.3.565
  8. BURKE F D. Primary care management of carpal tunnel syndrome. Postgraduate Medical Journal [online] 2003 August, 79(934):433-437 [viewed 11 April 2014] Available from: doi:10.1136/pmj.79.934.433

Examination

Fact Explanation
Hypalgesia There is diminished perception of painful stimuli along the palmar aspect of the index finger when compared to the little finger. [1] This is because the sensory innervation of the palmar aspect of the thumb, index, middle and ring finger is by the Median Nerve. [2]
Two point discrimination test The lack of two point discrimination can be noted along the sensory distribution of the Median Nerve on the palmar aspect of the affected hand. [1]
Wrist flexion test (Phalen's Sign) The patient is asked to keep both wrists flexed for a period of sixty seconds. In more than fifty percent of those with Carpal tunnel syndrome there will be exacerbation of parasthesia of the affected hand. [3]
Tinnel's percussion test Upon percussion of the Median Nerve over the flexor retinaculum there is hyperasthesia over the distribution of the Median Nerve. [4] Despite having high specificity (75%) it has a relatively low sensitivity (36%) [1]
Wasting of the thenar eminence Often seen in advanced cases. [3,4] In longstanding cases of carpal tunnel syndrome there is atrophy of the thenar eminence, as these muscles are supplied by the Median Nerve. [2] It is often easier to appreciate the loss of muscle bulk if palpation is performed during contraction of the muscles.
Weakness of thumb movements There is weakness of thumb abduction, adduction and opposition as the thenar muscles become progressively weaker. [4]
Evidence of secondary causes of carpal tunnel syndrome [4] Look for features of secondary causes of carpal tunnel syndrome in the general examination. [4] Possible features noted maybe hypothyroidism, rheumatoid arthritis, osteoarthritis, previous Colles fracture and acromegaly.
References
  1. LeBLANC Kim Edward, CESTIA Wayne. Carpal Tunnel Syndrome. Am Fam Physician. 2011 Apr 15;83(8):952-958. [viewed 11 April 2014]. Available from: http://www.aafp.org/afp/2011/0415/p952.html
  2. SINNATAMBY CHUMMY S ed. Last's Anatomy Regional and Applied. Eleventh Edition. Churchill Livingstone. 2006.
  3. MCCLAIN Alan ed. Hamilton Bailey's Demonstrations of Physical Signs in Clinical Surgery. Sixteenth Edition. John Wright and Sons Ltd. 1984.
  4. RUSSELL RCG, WILLIAMS Norman S, BULSTRODE Christopher JK ed. Bailey and Love's Short Practice of Surgery. Twenty third edition. Arnold. 2000.

Differential Diagnoses

Fact Explanation
Cervical spondylosis Spondylosis refers to the degenerative changes that may occur in the spine. Osteophytic overgrowth ventrally and, in some cases, buckling of the ligamentum flavum dorsally can cause direct compression of the spinal cord resulting in myelopathy. Common complaints are neck stiffness, neck, arm and shoulder pain and possibly stiffness or clumsiness while walking. [1]
Compartment syndrome Occurs when the pressure within the fascial compartments of the arm increases and causes disturbance to the blood flow. Acute compartment syndrome may be caused by a fracture, a large bruise to the muscle, re-establishment of blood flow after occlusion or constricting POP cast/plaster. [2]
Diabetic neuropathy Is a complication of long standing diabetes. Can occur in both type I and type II diabetes. The commonest presentation is of a distal symmetrical sensory polyneuropathy. [3]
Thoracic outlet syndrome Thoracic outlet syndrome (TOS) refers to abnormal compression of nerve, arterial and less frequently venous structures at the base of the neck or thoracic outlet. Majority of patients present with neurological symptoms such as pain, parasthesia, weakness and wasting of hand and arm. There maybe associated vascular symptoms such as coldness, cyanosis and swelling of the hands. [4]
Multiple sclerosis Is an autoimmune neurodegenerative disease that affects people between the ages of 20 and 40. Common symptoms are weakness and spasticity of limbs and visual defects due to optic neuritis. [5]
Medial epicondylitis Patients complain of aching pain over the medial aspect of the elbow. Weakness of grip is seen in more long standing cases. [2]
Lateral epicondylitis Usually presents with pain over the lateral elbow which worsens with activity and improves with rest. Aggravation of pain is felt when a backhand is played in tennis or the overuse of a screwdriver. [2]
Syringomyelia Syringomyelia often causes bilateral symptoms with wasting of the small muscles of the hand. There may be sensory dissociation of the affected region with loss of temperature sensation preceding the loss of pain sensation. [6]
Leprosy Presentation may be with anesthetic hypopigmented skin patches, wasting and muscle weakness, wrist drop and palpable thickened peripheral nerves.
References
  1. YOUNG William F. Cervical Spondylotic Myelopathy: A Common Cause of Spinal Cord Dysfunction in Older Persons. Am Fam Physician. 2000 Sep 1;62(5):1064-1070. [viewed 12 April 2014] Available from: http://www.aafp.org/afp/2000/0901/p1064.html
  2. RUSSELL RCG, WILLIAMS Norman S, BULSTRODE Christopher JK ed. Bailey and Love's Short Practice of Surgery. Twenty third edition. Arnold. 2000.
  3. THOMAS PK. Diabetic neuropathy: mechanisms and future treatment options. J Neurol Neurosurg Psychiatry 1999;67:277-279 [Viewed 12 April 2014] Available from: doi:10.1136/jnnp.67.3.277
  4. COOKE RA. Thoracic outlet syndrome—aspects of diagnosis in the differential diagnosis of hand–arm vibration syndrome. Occup Med (Lond) (2003) 53 (5): 331-336. [viewed 12 April 2014] Available from: doi: 10.1093/occmed/kqg097
  5. GOLDMAN Myla D, COHEN Jeffrey A, FOX Robert J and BETHOUX Francois A. Multiple sclerosis: treating symptoms, and other general medical issues. Cleveland Clinic Journal of Medicine February 2006 vol. 73 2 177-186 [viewed 12 April 2014] Available from: doi: 10.3949/ccjm.73.2.177
  6. NIEDERMAIER N. Cervical syringomyelia at the C7-C8 level presenting with bilateral scapular winging. J Neurol Neurosurg Psychiatry 2000;68:394-395 [viewed 12 April 2014] Available from: doi:10.1136/jnnp.68.3.394

Investigations - for Diagnosis

Fact Explanation
Magnetic Resonance Imaging (MRI) MRI features of carpal tunnel syndrome are: enlargement of the median nerve, this is often observed within the proximal carpal tunnel. More distally over the carpal tunnel the nerve becomes flattened with bowing of the flexor retinaculum. [1] In addition it is also useful to exclude a possible space occupying lesion of the carpal tunnel that can cause similar symptoms.
High resolution Ultrasound (HRUS) High resolution ultrasound (HRUS) has emerged as a simple, low-cost, rapid, accurate, and noninvasive imaging method for evaluating the Median Nerve. In addition to the detection of increased cross sectional area of the Median Nerve. Ultrasound is also useful for identifying ganglia, fibromata, neural tumors, and tenosynovitis that can cause similar symptoms. [2] Ultrasound can also be used to guide steroid injections into the tunnel.
Nerve conduction study Abnormalities of electrophysiologic testing, in addition to specific symptoms and signs, are needed in the diagnosis of carpal tunnel syndrome. Nerve conduction study (NCS) is more valuable than needle electromyography (EMG) study in general because of the underlying pathology of focal demyelination. [3] Electrophysiological assessment also provides a an idea of the severity of the damage inflicted on the Median Nerve and thereby guides subsequent therapeutic interventions.
References
  1. DONG Qian et al. Entrapment Neuropathies in the Upper and Lower Limbs: Anatomy and MRI Features. Radiology Research and Practice, vol. 2012 [viewed 12 April 2014] Available from: doi:10.1155/2012/230679
  2. AJEENA Ihsan M et al. Ultrasonic Assessment of Females with Carpal Tunnel Syndrome Proved by Nerve Conduction Study. Neural Plasticity, vol. 2013, [viewed 12 April 2014] Available from: doi:10.1155/2013/754564
  3. WANG Leilei. Electrodiagnosis of Carpal Tunnel Syndrome. Phys Med Rehabil Clin N Am 24 (2013) 67–77 [viewed 12 April 2014]. Available from: http://dx.doi.org/10.1016/j.pmr.2012.09.001

Investigations - Screening/Staging

Fact Explanation
Electrophysiological investigations [1] Staging is based on clinical and electrophysiologic criteria. Staging is as follows: Early - symptoms for less than one year, no permanent weakness and nerve conduction velocity increased by 1-2 ms. Intermediate- permanent weakness, prolonged latency. Advanced- permanent loss of sensory and motor function. [1] This system of staging is useful in guiding the therapeutic interventions.
References
  1. KLEINDIENST A., HAMM B., HILDEBRANDT G., KLUG N.. Diagnosis and staging of carpal tunnel syndrome: Comparison of magnetic resonance imaging and intra-operative findings. Acta neurochir [online] 1996 February, 138(2):228-233 [viewed 11 April 2014] Available from: doi:10.1007/BF01411366

Management - General Measures

Fact Explanation
Avoid repetitive hand movements [1] Repetitive movements may exacerbate symptoms and make symptom relief difficult. Should also avoid the use of vibratory tools. Ergonomic measures such as improved wrist positioning when using a keyboard maybe useful.
Wrist splints [1] Splinting the wrist at a neutral angle may help relieve symptoms. This works by reducing repetitive rotation and flexion and reducing the soft tissue swelling and tenosynovitis. Recommended for a period of four weeks. [1]
NSAIDS [1] Recommended as an adjunct to ergonomic measures and wrist splinting. [1]
Nerve and tendon gliding exercises [2] Useful in patients with mild to moderate symptoms.
References
  1. VIERA Anthony J. Management of Carpal Tunnel Syndrome. Am Fam Physician. 2003 Jul 15;68(2):265-272. [viewed 12 April 2014] Available from: http://www.aafp.org/afp/2003/0715/p265.html
  2. AKALIN E et al. Treatment of carpal tunnel syndrome with nerve and tendon gliding exercises. Am J Phys Med Rehabil. 2002 Feb;81(2):108-13. (viewed on 12 April 2014). Available from: http://www.ncbi.nlm.nih.gov/pubmed/11807347

Management - Specific Treatments

Fact Explanation
Corticosteroid injection [1] Steroid injections are very effective in resolving symptoms of carpal tunnel syndrome in the short term, particularly if symptoms are mild and intermittent. [2] Those with mild symptoms of short duration have more benefit than those with more protracted or severe symptoms.
Ultrasound [2] Limited benefit in providing relief from symptoms.
Supraretinacular endoscopic carpal tunnel release [3] Reduced pain and early return to work following surgery when compared to the conventional technique. Should be considered if non surgical treatment fails to alleviate symptoms. [3]
Carpal tunnel release and Median Nerve decompression [3] Traditional surgery is an out patient procedure that utilizes regional anesthesia. Surgery is indicated if symptoms do not respond to non surgical therapy and nerve conduction reveals severe entrapment neuropathy. [3] Possible complications are injury to the palmar cutaneous or recurrent motor branch of the median nerve, hypertrophic scarring, laceration of the superficial palmar arch, and tendon adhesion.
References
  1. O' GRADIAGH D. Corticosteroid injection for the treatment of carpal tunnel syndrome. Ann Rheum Dis 2000;59:918-919 [viewed 12 April 2014] doi:10.1136/ard.59.11.918
  2. BURKE FD et al. Primary care management of carpal tunnel syndrome. Postgrad Med J 2003;79:433-437 (viewed 12 April 2014) doi:10.1136/pmj.79.934.433
  3. VIERA Anthony J. Management of Carpal Tunnel Syndrome. Am Fam Physician. 2003 Jul 15;68(2):265-272. [viewed 12 April 2014] Available from: http://www.aafp.org/afp/2003/0715/p265.html