Definition

Carpal tunnel syndrome is a nerve disorder of the hand. It is caused by compression of the median nerve. The median nerve gets squeezed inside a narrow passage in the wrist called the carpal tunnel. This nerve provides feeling to the thumb, index and middle fingers, and half the ring finger.

Causes

Carpal tunnel syndrome is created by pressure on the median nerve. This pressure is caused by the carpal tunnel becoming narrower. The narrowing can be caused by many factors, including:

• Swelling of tissue in the carpal tunnel due to injury or fluid changes in your body
• Hereditary narrow carpal tunnel
• Tumors (rare)

Risk Factors

Women and older adults are at greater risk for carpal tunnel syndrome.

Factors that may increase your risk of carpal tunnel syndrome include:

• Obesity
• Excessive alcohol consumption
• Smoking
• Activities with repetitive hand motions:
  • Certain sports
  • Sewing
  • Playing musical instruments
  • Typing
  • Assembly tasks
• Water retention from:
  • Heart failure
  • Kidney problems
• Wrist injury:
  • Burns
  • Broken bones
  • Compression or crush injuries
• Arthritis
• Diabetes
• Raynaud’s disease and phenomenon, which impairs blood flow in the hands
• Hormone-related conditions:
  • Pregnancy
  • Breastfeeding
  • Menopause
  • Hypothyroidism
  • Cushing’s disease
  • Excess growth hormone
• Medications:
  • Birth control pills
  • Cortisone pills or shots
  • Some high blood pressure medications

Symptoms

Carpal tunnel syndrome causes symptoms in one or both hands or wrists. Symptoms may include:

• Tingling, burning, or numbness, especially in your thumb and index or middle fingers
• Pain or numbness that worsens with:
  • Wrist, hand, or finger movement
  • Sleep—symptoms may wake you
• Hand stiffness or cramping that gets better after:
  • Shaking your hand
  • Waking up in the morning
• Weakness or clumsiness of your hand:
  • Loss of grip strength
  • Difficulty making a fist
  • Frequently dropping things
• Pain that moves up your arm

Diagnosis

You will be asked about your symptoms and medical history. A physical exam of your arms, wrists, and hands will be done. The exam will include tests of strength, sensation, and signs of nerve irritation or damage.

Other tests may include:

• Electrodiagnostic exam —Measures and records the speed of electrical conduction in your median nerve to see if the nerve impulse in the hand is delayed
• MRI scan —A test that uses magnetic waves to make pictures of structures inside your body, in this case the neck
• X-ray —A test that uses radiation to take a picture of structures inside your body, especially bones
• Ultrasound—A test that uses sound waves to measure the width of your median nerve (may be used as a screening test or to guide injections)

Treatment

It is important to correct whatever is causing the carpal tunnel syndrome. Sometimes making simple changes in your workplace or home may help relieve symptoms.

Treatment may also include:

Prevention

You may reduce your chances of getting carpal tunnel syndrome by taking these steps:

• Minimize repetitive hand movements when possible.
• Alternate between activities or tasks to reduce the strain on your body.
• When using your wrists, keep them straight. Let your arms and shoulders share the stress.
• Use your whole hand or both hands to pick up an item.
• Avoid holding an object the same way for a long time.
• If you work in an office, adjust your desk, chair, and keyboard so you are in the best possible position:
  • Back straight
  • Feet flat on the floor or resting on a footrest
  • Knees level with or slightly lower than your hips
  • Shoulders in a neutral position, not forward or back
  • Elbows bent at a 90-degree angle
  • Forearms parallel to the floor and wrists straight
• Take breaks at least every hour to:
  • Rest or shake your hands
  • Massage your palms and backs of your hands
• Get regular aerobic exercise such as walking or swimming.
• Cut down on caffeine and smoking. These activities may reduce blood flow to your hands.

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