Osteoporosis: Risk Factors, DEXA Scan Interpretation & Best Drug Therapy 2025

Carpal Tunnel Syndrome: Symptoms, Nerve Conduction Study & Treatment Algorithm

# **Carpal Tunnel Syndrome (CTS): Symptoms, Nerve Conduction Study & Treatment Algorithm** ## **Definition** Carpal Tunnel Syndrome is **median nerve compression** at the level of the wrist within the **carpal tunnel**, leading to sensory and motor dysfunction in the **median nerve distribution**. --- # **Pathophysiology** * The **carpal tunnel** is a rigid space bordered by carpal bones and the **transverse carpal ligament**. * Conditions causing tunnel **volume increase** or **nerve vulnerability** → median nerve ischemia + demyelination. * Chronic compression → **axonal loss** → persistent weakness and atrophy. --- # **Causes / Risk Factors** ### **Local / Mechanical** * Repetitive wrist flexion/extension * Vibrating tool use * Wrist fractures/dislocations * Ganglion cysts, synovitis ### **Systemic** * Diabetes mellitus * Hypothyroidism * Pregnancy (fluid retention) * Rheumatoid arthritis * Obesity * Amyloidosis --- # **Clinical Features** ### **Symptoms** **Sensory:** * Numbness/tingling in **thumb, index, middle, radial half of ring finger** * Symptoms worse at **night** * **Shaking hand provides relief** (flick sign) **Motor:** * Weak grip, clumsiness * Difficulty holding objects * **Thenar muscle weakness** (abductor pollicis brevis) **Autonomic signs (less common):** * Dryness of skin over lateral 3½ fingers --- ### **Physical Examination** * **Tinel’s sign:** Tapping over carpal tunnel → tingling in median nerve area * **Phalen’s test:** Forced wrist flexion for 60 sec → reproduces symptoms * **Durkan’s test (carpal compression test):** Direct pressure over the tunnel → most sensitive * Thenar muscle **atrophy** in advanced disease --- # **Nerve Conduction Study (NCS) — Key Findings** NCS is the **gold standard**. ### **Motor conduction** * Prolonged **distal motor latency** (> 4.2 ms) of median nerve * Reduced CMAP amplitude if axonal loss ### **Sensory conduction** * Slowed sensory velocity * Prolonged **sensory latency** (> 3.5 ms) * Reduced SNAP amplitude ### **Comparison tests** * Median vs ulnar sensory latency to ring finger * Median–radial latency difference to thumb * Very sensitive in early disease ### **Grading** * **Mild:** Sensory slowing only * **Moderate:** Sensory + motor latency prolongation * **Severe:** Absent sensory response + low CMAP + thenar atrophy --- # **Diagnosis** * Clinical examination + NCS * Ultrasound: Median nerve cross-sectional area > **9–10 mm²** at carpal tunnel inlet * X-ray only if trauma suspected * Rule out differentials: cervical radiculopathy (C6), pronator syndrome, diabetic polyneuropathy --- # **Treatment Algorithm (Stepwise)** ## **1. Initial Conservative Management (Mild–Moderate CTS)** ### **a. Wrist Splinting** * **Night splint** in neutral position * Best first-line for nocturnal symptoms ### **b. Activity Modification** * Reduce repetitive wrist flexion * Ergonomic adjustments ### **c. NSAIDs** * Provides symptom relief, but **does not alter nerve pathology** ### **d. Corticosteroid Injection** * Local steroid injection gives **weeks–months of relief** * Useful in pregnancy * Avoid frequent injections (>3/year) --- ## **2. Consider Further Evaluation** * Failure of conservative therapy in **6–12 weeks** * Progression of weakness * Severe findings on NCS --- ## **3. Definitive Treatment — Surgery** ### **Surgical Indication** * Persistent symptoms despite conservative therapy * Severe CTS (thenar atrophy or axonal loss on NCS) * Recurrent symptoms significantly affecting function ### **Procedure** **Carpal Tunnel Release (CTR)** * Cut the transverse carpal ligament to decompress the median nerve * Approaches: **open** or **endoscopic** ### **Outcomes** * Excellent symptom improvement in majority * Thenar strength recovery depends on duration of compression * Recurrence is uncommon --- # **Prognosis** * Early-stage CTS responds well to conservative therapy * Long-standing compression with axonal damage → incomplete recovery * Diabetes: slower improvement * Pregnancy: symptoms often resolve postpartum --- # **Red Flags (Suggest Alternative Diagnosis)** * Whole-hand numbness (not median distribution) * Neck pain + hand paresthesia → cervical radiculopathy * Symptoms not affected by wrist position * Marked weakness without sensory loss → motor neuron or peripheral nerve disorder ---