Trigger thumb is a common repetitive strain injury that locks the thumb in a bent position making it difficult to perform everyday tasks, according to the MayoClinic.com. Trigger thumb occurs when the tendon that runs through the thumb deteriorates causing inflammation, irritation, swelling and a painful “catching” or clicking in the thumb. Although there are many causes of trigger thumb, various medical conditions along with certain environmental factors can play a significant role in its development.
Repetitive Strain
Trigger thumb occurs when repetitive hand movements put a strain on the tendons in the thumb, according to California’s Mairs Chiropractic Clinic. Repetitive strain on the hands through heavy lifting, typing or long hours at a steering wheel can cause the tendons in the thumb to become inflamed and irritated. Repeated motion can predispose someone to a variety of injuries such as trigger thumb. Overused thumb tendons can initiate the condition or cause it to worsen. Strained tendons can occur when muscles continuously contract from holding a cell phone while texting, typing, or holding something still for long periods of time while making small repetitive movements such as keeping the car steady while turning the steering wheel in different directions.
Diabetes
Diabetes can contribute to the onset of trigger thumb when the tendons in the hand become inflamed. Diabetes is an autoimmune disease in which the body attacks the cells in the pancreas that produce insulin, according to the website Science Daily. This disease can cause inflammation in people who have an imbalance in cytokines, proteins that regulate various inflammatory responses. Various parts of the body can become inflamed when the immune system attacks insulin cells. People with diabetes may experience limited range of mobility or the inability to fully flex or extend the fingers as a result of inflamed tendons in the hand, according to the website Diabetic Lifestyle. In addition, people with diabetes have a low immune system, so when they injure their hands, they tend to heal from the injury at a slower rate than those without the condition, resulting in additional inflammation and strain on the tendons connected to the thumb.
Rheumatoid Arthritis
Trigger finger or thumb is sometimes associated with an underlying illness that can cause inflammation of tissues of the hand such as rheumatoid arthritis (RA). RA affects the cells that lubricate the joint and make up the lining also called the synovial tissue, according to the website L.A Hand Surgeon. This condition can affect the whole body or many of its joints. When RA is present the joint lining gets inflamed and swells, resulting in cartilage and bone erosion. Joints may become unstable and distorted when swollen tissue stretches the ligaments that tie the bones that surround the joint together. Rheumatic inflammation can cause the tendons, which are rope-like structures that bind the bones to the muscle to expand and rupture. Although this type of arthritis can show up anywhere, with respect to the hand, it usually appears in multiple fingers such as the wrist, middle finger, knuckles or thumb. In addition, many people with RA have inflammation around the tendons of the palm of the hand that can cause stiffness and pain in the fingers or thumb.
