Transthyretin amyloid cardiomyopathy (ATTR-CM) is most often associated with cardiac symptoms but can also include nerve pain and other neurological symptoms.
Amyloid deposits can accumulate in the peripheral nervous system, causing inflammation and nerve dysfunction. This can affect the quality of life in people living ATTR-CM, with pain, discomfort and less mobility disrupting routine daily activities.
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.
What is peripheral neuropathy?
In ATTR-CM, abnormal folded protein transthyretin, called amyloid fibrils, is deposited in the heart, causing the left ventricle to stiffen and thicken, making it more difficult for the heart to pump blood.
Read more about ATTR-CM signs and symptoms
Amyloid fibrils can also accumulate in the peripheral nervous system, causing the degeneration and dysfunction of the nerves. The nerves of the peripheral nervous system include the nerves that run from the spinal cord and brain, and ATTR-CM may cause motor, sensory (pain, weakness) and autonomic (chronic diarrhea, erectile dysfunction) dysfunction.
When amyloid deposits accumulate on nerve cells, they damage the protective covering called myelin and disrupt nerve signaling. This affects balance and sensation and leads to peripheral neuropathy.
Nerve pain in ATTR-CM
The most common symptoms of peripheral neuropathy in ATTR-CM are nerve pain, numbness and tingling in the hands and feet, carpal tunnel syndrome and spinal stenosis.
There are two types of ATTR-CM: wild-type ATTR-CM (wATTR-CM), the most common form, which is due to a gene mutation, and hereditary ATTR-CM (hATTR-CM), which is passed down in the family.
Carpal tunnel syndrome (CTS) has been found to occur in up to 50% of people with wATTR-CM, in which the buildup of amyloid deposits in the wrists compresses the nerves and causes nerve pain, numbness, weakness and tingling in the fingers.
Spinal stenosis is also more common in wATTR-CM and is due to the accumulation of amyloid deposits in the back, resulting in lower back pain, numbness and tingling in the legs or feet or nerve pain down the leg.
Managing nerve pain in ATTR-CM
As soon as you start experiencing nerve pain, numbness or tingling, you should add a neurologist to your health care team.
The regular ATTR-CM medication you use to manage heart-related symptoms works to slow or stop disease progression by preventing the proteins from misfolding. This will also ease nerve pain as amyloid deposits stop accumulating in the nervous system.
In the case of CTS and spinal stenosis, steroid injections or surgical intervention are both options to ease the pressure on the compressed nerves.
Research is also ongoing into the antibody-mediated removal of amyloid deposits.
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