Definition

Carpal tunnel syndrome (CTS) is a common condition affecting people in productive age groups who perform hand-intensive tasks such as typing, writing, and sewing. CTS is caused by compression of the median nerve (n. medianus). The carpal tunnel is a passageway in the palm surrounded by bones and ligaments. When the median nerve is compressed or pinched, symptoms such as numbness, weakness, and pain in the hand and arm can occur.

This condition is influenced by the anatomy of the hand, health issues, and repetitive hand movements. Proper treatment can reduce numbness and restore wrist function, allowing you to resume normal activities.

Causes

CTS is caused by pressure on the median nerve. The median nerve innervates the hand, allowing you to feel touch in the thumb and fingers on the palm side of the hand. It also signals muscles to move the thumb. The median nerve originates from the brachial plexus in the upper arm and travels to the hand through the wrist, passing through the carpal tunnel. Any action that compresses, pinches, or irritates this tunnel can irritate the median nerve. Repetitive activities like typing, writing, or sewing can compress the carpal tunnel. Without treatment, the median nerve can become compressed, causing pain, numbness, and weakness in the hand, known as CTS.

In addition to repetitive movements, wrist fractures can narrow the carpal tunnel and irritate the median nerve. Inflammation from rheumatoid arthritis can also cause swelling and irritate the median nerve.

Risk factor

Several risk factors are associated with CTS. While not directly causing CTS, some can increase the risk of median nerve irritation leading to CTS:

• Occupation: Jobs with repetitive movements such as typing, sewing, cashiering, playing musical instruments, and hairdressing can irritate the median nerve, especially if the hand is positioned lower than the wrist. Working with vibrating tools and in cold environments also increases the risk of CTS.
• Anatomical Factors: Injuries leading to wrist fractures, dislocations, or arthritis can alter the carpal tunnel, irritating and compressing the median nerve. Some people naturally have smaller carpal tunnels, increasing their risk of CTS.
• Gender: Women are more likely to experience CTS due to having smaller carpal tunnels than men.
• Nerve-Damaging Conditions: Chronic diseases like diabetes can increase the risk of nerve damage, including to the median nerve.
• Inflammatory Conditions: Conditions like rheumatoid arthritis and others causing chronic inflammation can affect tendon sheaths in the wrist, impacting the carpal tunnel and compressing the median nerve.
• Medications: Some studies link CTS to medications for treating breast cancer.
• Obesity: Being overweight is a risk factor for CTS.
• Pregnancy: Hormonal changes during pregnancy can increase CTS risk.
• Mouse Usage: Some research suggests using a computer mouse may increase CTS risk more than keyboard use, though the evidence is not conclusive.

Symptoms

Symptoms of CTS include:

• Numbness and Tingling: You may feel numbness and tingling in the hand and fingers, usually in the thumb, index, and sometimes middle and ring fingers, but not the little finger. This sensation can extend to the upper arm and often occurs when driving, holding a phone, reading, or during static hand positions. Shaking the hand may relieve discomfort. Symptoms can become constant over time.
• Weakness: CTS can cause hand weakness, making you more prone to dropping objects. This weakness may result from numbness, tingling pain, or muscle weakness innervated by the median nerve.

Diagnosis

Doctors may perform several tests to diagnose CTS, including:

• Medical History: Questions about your symptoms, pain patterns, family history, other medical conditions, and daily activities. Since the median nerve does not innervate the little finger, you may experience pain in all fingers except the little finger.
• Physical Examination: The doctor may perform movements and ask if they cause wrist pain. Common tests include Tinel's sign (tapping the wrist) and Phalen's maneuver (bending the wrists downward for a few minutes). Sensation tests like two-point discrimination may also be conducted.
• X-ray: To rule out other causes of pain such as fractures or arthritis.
• Electromyography: Measures electrical activity in muscles. The doctor inserts a needle electrode to evaluate muscle activity during contraction and rest, identifying median nerve muscle damage.
• Nerve Conduction Study: A variation of electromyography to assess electrical activity in muscles.

Management

CTS treatment should begin as soon as symptoms appear:

• Splinting: Wearing a wrist splint at night can reduce symptoms and improve sleep quality, even if only used at night.
• Pain Relievers: Medications like acetaminophen and ibuprofen can temporarily reduce pain but do not cure CTS.
• Corticosteroids: Injections into the wrist can reduce inflammation and swelling, relieving median nerve compression. Consult your doctor about this option.
• Surgery: If symptoms do not improve with other treatments, endoscopic or open surgery may be recommended. Discuss the benefits and risks with your doctor.

Self-care at home

To reduce CTS pain, consider:

• Yoga: Strengthens upper limbs to reduce pain.
• Periodic Breaks: Take breaks from repetitive hand tasks.
• Weight Control: Maintain a healthy weight.
• Wrist Exercises: Rotate and stretch the wrist.
• Pain Relievers: Use as needed.
• Avoid Hand Pressure During Sleep: Do not sleep on your hands.
• Wrist Splints: Available at pharmacies.

Complications

Complications are rare, but CTS can significantly impair hand function. Immediate treatment improves the quality of life for those affected.

Prevention

While no definitive prevention strategies exist, you can reduce hand and wrist stress with these steps:

• Reduce Pressure and Relax Hand Movements: Type lightly, and use large, soft-grip pens with free-flowing ink to minimize hand pressure.
• Take Breaks: Regularly rest and stretch your hands, especially when using heavy tools.
• Maintain Proper Position: Avoid continuous wrist bending. Keep hands comfortably positioned, with the keyboard at or below elbow level.
• Change Your Mouse: Use a comfortable mouse.
• Keep Hands Warm: Cold environments increase pain and stiffness risk.

When to see a doctor?

Seek medical attention if you experience CTS symptoms affecting productivity and sleep quality. Untreated, CTS can cause permanent nerve and muscle damage.

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