Dr John Quinn, consultant haematologist at Beaumont Hospital, Dublin, recently answered some frequently asked questions about amyloidosis, why it can be confused with multiple myeloma, and how it may affect some people with multiple myeloma
What is amyloidosis?
Amyloidosis is actually the name given to a group of diseases, the most common of which is light chain amyloidosis. This is the most frequently diagnosed type, also known as AL amyloidosis. That accounts for about 60% of diagnosed amyloidosis cases. The other 40% is made up of a mixture of different types of amyloidosis; for example there are rare hereditary forms, a type that complicates chronic infections, and there is a type that we encounter in older people called transthyretin amyloidosis (TTR).
How is amyloidosis linked to multiple myeloma?
The type that overlaps with multiple myeloma is light chain amyloidosis. The reason these conditions are often grouped together and seen as related is because light chain amyloidosis, like myeloma, is also a plasma cell disorder, with the plasma cell at the heart of the problem. The plasma cell makes an abnormal protein which becomes “misfolded” and eventually forms amyloid. Amyloid is an abnormal protein complex that then gets deposited in organs and can cause problems. The other link with myeloma, is because it is a plasma cell disease, we use very similar medications to treat both conditions. They are separate diseases, however, a small minority of myeloma patients can
develop amyloidosis as a complication of myeloma during the course of their illness. If it does occur in the setting of multiple myeloma, it does present treatment challenges.
What are the symptoms of amyloidosis?
The main organs affected in light chain amyloidosis are the heart, kidneys, liver, and nervous system. The symptoms that people develop tend to reflect the organs involved. The most common symptoms we would see would be shortness of breath and fatigue, particularly if the heart is involved, and lower limb swelling if the kidneys and/or heart are involved. Numbness and tingling in the peripheries [arms and legs] can also happen if there is nervous system involvement. Gut upset and diarrhoea can also occur. Patients can also get tongue enlargement and occasionally can experience easy bruising. These are the most common symptoms we tend to see.
How difficult is it to diagnose?
It is a rare illness – we probably see one light chain amyloidosis case for every 10-15 multiple myeloma cases. It can be a difficult diagnosis to make and because the symptoms are non-specific, a patient can see a number of doctors before a diagnosis is made. This means the disease can be at an advanced stage and if the heart is involved, then it becomes more difficult to manage and has a poorer outlook.
When would you suspect amyloidosis in a multiple myeloma patient?
If a patient develops symptoms that are out of line with what we would expect then we would work to rule out amyloidosis. If I see a multiple myeloma patient who heretofore has been pretty stable and all of a sudden is complaining of severe fatigue out proportion to where you’d expect to be, or if the patient has developed heart disease or kidney disease. Or when we know the myeloma doesn’t seem to be active, we know something new has developed. It can be subtle, and difficult to detect, even for experienced doctors. We take it on a case by case basis. And if a patient suspects something has changed with their symptoms, they should discuss this with their doctor.