Transthyretin amyloid cardiomyopathy (ATTR-CM) doesn’t just mean cardiovascular symptoms. It can also impact the muscles and bones, leading to carpal tunnel syndrome, spinal stenosis, shoulder, hip and knee pain — and trigger finger. Trigger finger (stenosing tenosynovitis) is a consequence of ATTR-CM that occurs when amyloid fibrils collect in the connective tissues.
What are amyloid fibrils?
In ATTR-CM, amyloid fibrils are clumps of faulty, misfolded TTR proteins that are deposited in the heart, nerves and internal organs. In the heart, fibrils affect the left ventricle, causing the heart tissue to thicken and stiffen. This makes it more difficult for the heart to pump blood around the body and can lead to heart failure.
What is trigger finger?
When amyloid deposits accumulate in the connective tissue they cause the tendons to thicken, stiffen and become inflamed. This restricts the movement of a finger’s flexor tendon, stopping it from gliding smoothly back and forth in the sheath around it. As a result, the finger can catch when it is bent, and become locked in this position. Unbending the finger may cause a clicking sound; the finger may straighten with a quick snap, like the pulling of a trigger. Straightening the bent finger is often painful, especially as time goes on.
Trigger finger mostly affects the ring finger or thumb, but can affect other fingers as well.
Recent research has shown that musculoskeletal symptoms such as carpal tunnel, spinal stenosis and trigger finger can be precursors to ATTR-CM. In some cases, a biopsy taken during trigger release surgery has led to a diagnosis of ATTR-CM.
Symptoms of trigger finger
The onset of trigger finger typically begins with pain or discomfort at the base of the affected finger. Symptoms can develop over a period of weeks or months.
Other symptoms may include:
- Thickening or swelling at the base of the finger.
- A popping or clicking sound when bending and straightening the finger.
- Stiffness of the finger in the morning.
- The finger occasionally locking in a bent position.
- Several fingers affected at the same time.
Treating trigger finger in people with ATTR-CM
Following a diagnosis of trigger finger in a person living with ATTR-CM, their healthcare team will review the best treatment options.
Medication prescribed to treat ATTR-CM slows or stops disease progression, which means amyloid deposits no longer accumulate in the body at the same rate, or at all. However, it doesn’t cause existing deposits to break down — meaning ATTR-CM medications won’t help with trigger finger symptoms once they have developed.
Read more about ATTR-CM therapies
A nonsurgical approach to treating trigger finger will be the first step, with gentle exercises to stretch and help improve the flexibility of the finger. A splint may be recommended while sleeping, to prevent the finger from becoming bent overnight. Over-the-counter medication to help alleviate pain and reduce inflammation is also likely to be advised. Steroid injections of cortisone can also be effective in reducing inflammation.
However, if none of these options are successful, surgical intervention known as trigger release surgery will be considered. This surgical treatment opens the tendon sheath to restore movement.
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