- The amyloid deposits most commonly affect the heart. This causes the heart wall to slowly stiffen and therefore not function properly (restrictive cardiomyopathy), leading to heart failure and heart rhythm problems.
- Heart involvement in patients with ATTRwt is often less severe at diagnosis than in AL cardiac patients and it usually progresses at a slower pace.
- Small deposits can occur in the soft tissue of the wrist causing the painful condition known as carpel tunnel syndrome. This condition is often experienced many years before the diagnosis of ATTRwt is made.
- Amyloid deposits are sometimes found in the lumbar spine and various ligaments and tendons and in the bladder
Click to the section organ involvement for more information on the heart.
Symptoms vary from patient to patient and can often be vague especially in early disease and mimic other diseases.
- Shortness of breath on exertion.
- Intolerance to exercise
- Oedema, swelling of feet and legs.
- Slow heart rate leading to dizziness or blackouts when moving from sitting to standing or exercising
- Chest pain (angina)
- Disrupted sleep
- Weight loss
- Carpel tunnel syndrome (numbness, tingling in the fingers and hands)
- Nerve pain in a very small number of patients related to Lumbar spinal stenosis.
- Blood in the urine
Diagnosing Wild type ATTR (ATTRwt)
A cardiologist may suspect amyloidosis when symptoms of heart failure are being investigated.
- A diagnosis may still be made through a tissue or organ biopsy
- The biopsy is stained with the dye Congo red in the laboratory.
- If amyloid is present, the biopsy will appear red under normal light and green (apple-green birefringence) under special polarized light.
- Now a days a less intrusive method of diagnosis s often used. A DPD or PYP bone scan can diagnose heart involvement in ATTR amyloidosis, enabling the diagnosis to be reliably made without the need for a tissue biopsy.
- This procedure is not reliable in patients with a monoclonal gammopathy.
2nd procedure in the laboratory
- If a biopsy has been taken further testing may be done to classify the type of amyloidosis by identifying the protein composition of the amyloid fibrils.
- It is imperative to identify the “type” as treatment is different for each type of amyloidosis.
- This is particularly important as it is easy for ATTRwt amyloidosis to be mistaken for AL amyloidosis. These two types of amyloidosis have very different outcomes and have very different therapies.
Over the decade new diagnostic tools have improved the ability to diagnose cardiac amyloidosis.
These advances, which include echocardiography with strain imaging, cardiac magnetic resonance imaging (MRI) and bone scintigraphy (DPD or PYP scans) are giving cardiologists the option to diagnose ATTRwt amyloidosis earlier, with more confidence, and in some cases without an organ biopsy.
The following tests may be performed to help with diagnosis, assess organ involvement and damage and monitor organ function.
- Genetic testing to exclude the hereditary type of ATTR
- Tissue biopsy
- MRI of the heart
- Cardiac biomarkers (troponin and BNP or NT-ProBNP)
- DPD or PYP scan. (Traditionally used for imaging bones, these scans involve special molecules which are injected into the body and become trapped in the heart when it is full of transthyretin amyloidosis thus helping with the diagnosis and identification of this type of amyloid.)
Once the diagnosis is made the primary care specialist will usually be a cardiologist.