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Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy and one of the most commonly reported occupational diseases. Sandra Ghiasse and Anne Harriss examine the impact of CTS on the performance of an employee during a fitness for work assessment.
The carpal tunnel, a narrow, rigid passageway of ligament and bones in the wrist, houses the median nerve and tendons. Swelling of structures within this tunnel causes median nerve compression and carpal tunnel syndrome (CTS) results. It is characterised by pain, weakness and numbness in the wrist and hand.
Symptom onset is usually gradual, starting with discomfort, tingling, or numbness in the hand, thumb, index, middle and ring fingers, subsequently limiting manual dexterity causing difficulty in grasping small objects. If left untreated, chronicity develops, which includes muscle wastage at the base of the thumb.
Anatomical factors can be key, as the carpal tunnel may be smaller in some people, particularly women, who are therefore more likely to develop CTS than men. Other factors contributing to symptom development include metabolic disorders such as: hypothyroidism and diabetes; obesity; trauma; rheumatoid arthritis and using vibrating tools (National Institute of Neurological Disorders and Stroke (NINDS), 2015).
Early diagnosis and treatment is vital in avoiding irreversible median nerve damage. Assessment of the hands and arms involves noting discoloration, swelling, warmth and tenderness as these may indicate CTS. Sensation and finger strength is assessed, as is the presence/absence of atrophy of the muscle at the base of the thumb.
Two standard tests in the diagnosis of CTS include Tinel and Phalen's. The Tinel test involves the clinician percussing the median nerve in the patient’s wrist. Tingling in the fingers or the occurrence of shock-like sensations indicate a positive result. Phalen’s test invo-lves the patient pressing the back of the hands together, with the fingers pointing downwards for 60 seconds. Tingling or numbness suggests CTS, and this can be confirmed by nerve conduction studies. Abnormal median nerve size may be identified using an ultrasound (NINDS, 2015).
Carpal tunnel syndrome case study
Mrs Brown, a 55-year-old cleaner, was seen by an OH adviser as a management referral following her repeated short-term absences associated with a three-month history of wrist pain. She had been in her employment full-time for 10 years and