Transthyretin amyloid cardiomyopathy (ATTR-CM) is most often associated with symptoms similar to those of other types of heart failure: fatigue; shortness of breath; coughing or wheezing; swelling of feet, legs and ankles; and bloating of the stomach.
But other conditions can occur when amyloid deposits of the faulty transthyretin protein accumulate in other parts of the body; they include carpal tunnel syndrome (CTS) and spinal stenosis.
What is ATTR-CM?
Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is a rare progressive disease of the heart muscle that leads to congestive heart failure. It occurs when the transthyretin protein produced by the liver is unstable. Symptoms include fatigue; shortness of breath; irregular heart rate or palpitations; swelling of the legs, ankles and stomach; brain fog; wheezing; and dizziness. It often goes underdiagnosed because of a lack of awareness and knowledge of the disease. There is currently no cure for ATTR-CM.
CTS has been shown to occur in patients with ATTR-CM before any cardiac symptoms, so it can be predictive of a diagnosis of ATTR-CM. With diagnosis of ATTR-CM often taking up to six years, the presence of CTS could help facilitate earlier detection of ATTR-CM.
What is carpal tunnel syndrome?
CTS is a common hand condition caused by pressure on the median nerve in the wrist. It often occurs in both wrists and may result from repetitive movements or arthritis.
Symptoms of CTS include pain, tingling, numbness and weakness in the hand and wrist. It is more common in women over 50 years old, and treatment may include anti-inflammatories, a splint to reduce movement, stretching and specific exercises and surgery to relieve the pressure on the nerve.
Carpal tunnel syndrome and ATTR-CM
In ATTR-CM, amyloid deposits build up in the heart, nerves and other organs of the body. In the heart, the left ventricle thickens and stiffens, making it difficult to pump blood to the rest of the body. If left untreated, the disease progresses and eventually leads to heart failure.
In CTS, amyloid deposits accumulate in the carpal tunnel tissue of the wrist, causing the ligaments and tendons to thicken and press on the median nerve. A link between CTS and ATTR-CM has been established through the detection of amyloid deposits in the carpal tunnel tissue by a tissue biopsy.
About 50% of people living with ATTR-CM have a history of CTS. This means that CTS could be an early disease marker for the development of ATTR-CM, more commonly the wild-type subtype or wATTR-CM.
Treatment of CTS in ATTR-CM
Medication to slow disease progression in ATTR-CM can help slow or stop amyloid deposits.
In people with ATTR-CM, the symptoms of CTS often affect both wrists, and surgery is the best option. The procedure called carpal tunnel release (CTR) is effective and low risk, with the patient able to make a quick recovery. It is worth noting that there is a high recurrence rate, and the procedure sometimes needs to be repeated.