Case Report of Infection Linked with Trigger Finger

A rare case is reported here of a trigger finger linked to an infection from Mycobacterium kansasii. A 38-year old woman in good health cut her finger while cutting vegetables. She washed it off with tap water. It seemed to heal just fine.

Later she noticed tenderness along the palmar side of her middle finger. A trigger finger developed causing her to seek medical attention. A trigger finger occurs when the tendon can't slide smoothly through the tendon sheath (lining around it).

Trigger finger is also known as stenosing tenosynovitis. Tenosynovitis refers to swelling of the tendon sheath. Stenosis means a narrowing of the space for the tendon.

The tendon makes a cracking sound when the finger is moved. It gets stuck in a flexed position and then makes a popping sound when the finger unlocks, as if releasing the trigger on a gun.

A diagnosis of stenosing tenosynovitis was made based on her clinical presentation. She was treated with two steroid injections into the tendon sheath. Triggering, stiffness, and pain persisted.

Surgery was done to release the A1 pulley of the middle finger. The pulley is part of the tendon mechanism that allows for smooth and controlled movement through the sheath. At the time of the operation, the surgeon did not see any sign of scarring, infection, or swelling of the tendon.

Two weeks after the surgery, there was still pain and stiffness with limited motion. A hand therapist treated her. Her motion improved but the pain and tenderness remained. A third steroid injection was tried without success. This was followed by another surgery.

At the time of the second operation, the tendon sheath was thickened and full of synovial fluid. Further testing showed inflammation, dead tissue, and a positive culture for Mycobacterium kansasii.

The problem finally cleared up with antibiotics. The patient had full and pain free motion. The surgeon could not be sure if the infection came from the tap water used to rinse the wound originally or from a contaminated needle during the steroid injection. Once the proper diagnosis and treatment were given, no further treatment was needed.