Anything that causes irritation, inflammation, fluid retention, or an abnormal growth in or around the carpal tunnel can cause carpal tunnel syndrome, including:

• Repetitive movements of the hands, wrists, or fingers—especially overactive use of a computer keyboard, certain musical instruments, or hand tools
• Use of vibrating equipment or tools
• A narrow carpal tunnel (due to heredity or other causes)
• Wrist injury:
  • Burns
  • Broken bones
  • Compression or crush injuries
• Arthritis leading to swelling within the carpal tunnel
• Diabetes
• Raynaud disease, which impairs blood flow in the hands
• Water retention due to:
  • Kidney disease
  • Amyloidosis
  • Coronary artery disease
• Hormone-related conditions, such as:
  • Pregnancy
  • Breastfeeding
  • Menopause
  • Hypothyroidism
  • Cushing disease
  • Excess growth hormone
• Medications, such as:
  • Birth control pills
  • Cortisone pills or shots
  • Some high blood pressure drugs
• Tumors and cysts in the carpal tunnel