SEARCH RESULTS FOR: Carpal-Tunnel-Syndrome

Carpal Tunnel Syndrome

Carpal Tunnel Syndrome: Pathogenesis and clinical findings Diabetes Mellitus (See Pathogenesis Slide) ↑ Blood sugar: deposition of advanced glycation end (AGE) products (proteins or lipids glycated when exposed to sugar) AGE attaches to and prevents tendons from moving properly Authors: Amanda Eslinger Yvette Ysabel Yao Reviewers: Matthew Harding Owen Stechishin Mao Ding, Cory Toth* * MD at time of publication Wrist trauma (distal radius fractures, carpal/metacarpal fractures, tendon ruptures) Repetitive Strain Injury (repetitive hand & wrist movements) Irritation, swelling & thickening of tendons in carpal tunnel Calcium deposits Calcifica tion Deposition Amyloidosis Amyloid (protein aggregates) deposition Gout (See Gout Slide) Uric acid crystal deposition Pregnancy ↑ Concentration of hormones & uterine pressure on inferior vena cava Backup of blood into systemic circulation Autoimmune (i.e. Rheumatoid arthritis, scleroderma, lupus, Sjogren’s syndrome) ↑ Inflammatory cytokines causing inflammation Hypo- thyroidism Myxedema (swelling of skin and underlying tissues) in carpal tunnel Idiopathic or Congenital Edema Narrowed carpal tunnel leads to ↑ internal pressure Carpal Tunnel Syndrome Vascular: median artery thrombosis in carpal tunnel Median nerve compression inside the carpal tunnel Mechanical disruption of median nerve Compression exacerbated with flexed wrists (i.e. sleep, driving, holding phone/cup) Disruption of daily activities and sleep Ischemia (↓ blood supply) to median nerve Hypoxia (↓ oxygenated blood flow) Metabolic conduction block (impaired axonal transport due to ischemia) Nerve conduction study (show sensory nerve impulses slowing across the wrist, followed by mild / moderate / severe loss of sensory nerve amplitude Damage to the myelin sheath ↓ Saltatory conduction (action potential propagation along myelinated axons) Neuropraxia (nerve compression blocks conduction) Interruption in axonal continuity Axonotmesis (endoneural tube stays intact but myelin & distal axon degenerates) Recovery possible Full disruption of myelin, axon & nerve sheath Neurotmesis (axons no longer have an endoneural tube to guide regrowth) Recovery impossible ↓ Ability to contract and use abductor pollicis brevis muscle ↓ Signals through median nerve Interference with signals to the brain causes unusual sensations Hypoalgesia (↓ pain Dysesthesia (tingling, burning, or sensitivity at 1st 3 1⁄2 digits) painful sensation at 1st 3 1⁄2 digits) Thenar muscle wasting Reduced hand dexterity Weak thumb abduction Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published December 2nd, 2013, updated March 22, 2023 on www.thecalgaryguide.com