What’s amyloidosis and why is it often diagnosed late?
Fred Hutch Cancer Center’s Andrew Cowan, MD, who treats the disease, said delayed diagnosis is unfortunately quite common.
“It’s an uncommon condition, so physicians often don’t consider the diagnosis,” he said. “It’s often diagnosed at a more advanced stage. Although survival has improved, some patients, especially those with advanced cardiac involvement, still don’t benefit as much from therapy.”
In light chain amyloidosis, abnormal plasma cells, which normally make protective immune proteins called antibodies, instead produce amyloidogenic light chains (a component of antibodies). These light chains misfold, depositing in various tissues and organs throughout the body.
Depending on where they land, the symptoms can be subtle or sudden, as in the pulmonary edema that Cox experienced while snorkeling in Hawaii.
That was her first indication that anything was wrong.
“I almost drowned due to massive pulmonary edema, but I was very physically fit and didn’t have the typical indications for someone with cardiomyopathy, which would have caused that,” she said. “Also, I didn’t have diabetes. So they went down the rabbit hole of rare diseases.”
Cowan said the deposits can cause issues with multiple organs over the years, although some people have few symptoms until the condition is prevalent.
“When they’re in the tissues, the amyloid fibrils are like concrete, they’re stiff,” he said. “Over time, the deposits affect the organs and then they can’t function properly. And it can happen to almost any organ.”
There are also different forms of the disease, including one that’s hereditary (transthyretin or TTR amyloidosis). Most people, like Cox, are diagnosed with AL amyloidosis, also known as primary amyloidosis. There are no known ways to prevent it.
What are the symptoms?
The main reason for late diagnoses is that warning signs and symptoms can be nebulous and are often mistaken for other conditions.
People with amyloidosis deposits in their heart, for instance, may have shortness of breath, abnormal heart rhythm, chest pain, fainting or difficulty with physical activity.
“With cardiac amyloidosis, your heart hardens and loses its ability to pump blood efficiently,” Cox said. “It doesn’t feed blood to the left ventricle adequately. It’s cardiomyopathy to the extreme. When I was diagnosed, the doctor said my heart would never get better. They’re not saying that now, though. A recent CT scan showed my heart is healing.”
Kidney-related symptoms include decreased urine output, foamy urine and swelling in the lower legs, belly, arms and lungs. Nerve-related symptoms of amyloidosis include pain, numbness or tingling (also known as peripheral neuropathy) in the hands or feet; dizziness when standing quickly; bowel problems or erectile dysfunction and carpal tunnel syndrome. An enlarged tongue — known as macroglossia — can also be a symptom. Read more about the signs and symptoms of this condition here.
“Over time, folks with renal amyloidosis can develop end-stage renal disease and require dialysis,” Cowan said. “If it lands in the heart, patients can develop heart failure. We can consider heart transplants for a few patients, but in general if the damage is done, it can often be challenging to reverse. I’ve lost too many patients in the first six to 12 months after diagnosis because it took them forever to get a diagnosis.”
As with cancer, the earlier the diagnosis, the likelier the patient can be treated successfully.
“There were few treatments really when I was diagnosed,” Cox said. “But that was back in the day, five years ago.”