Amyloidosis (Deposition of amyloid fibrils): Symptoms, Causes, Diagnosis & Treatment

Amyloidosis is a clinical disorder caused by extracellular and/or intracellular deposition of insoluble abnormal amyloid fibrils that alter the normal function of tissues. Symptoms depend on which organs are affected. They may include swelling, fatigue and weakness, shortness of breath, numbness, tingling, or pain in the hands or feet. Depending on the type of amyloidosis, medication, chemotherapy or a stem-cell transplant may be pursued.

There are different types of amyloidosis, depending on the tissue being affected:

  • Light chain (AL) amyloidosis – This is the most common type of amyloidosis. The amyloid proteins that build up in the tissues in this condition are known as light chains. They can either be kappa or lambda light chains. AL amyloidosis is a disorder of the plasma cells. Plasma cells are a type of white blood cells responsible for the production of immunoglobulins or antibodies, which are a type of protein that fight infection. In AL amyloidosis, the light chain proteins are misshapen and produced in excess. They deposit in tissues and can damage one or more organs. The heart, kidneys, nerves, and gastrointestinal system are the most common organs affected. Because AL amyloidosis is associated with the overproduction of plasma cell proteins, it is linked to multiple myeloma.
  • Autoimmune (AA) amyloidosis – AA amyloidosis is also called “secondary amyloidosis” or “inflammatory amyloidosis.” In this condition, the amyloid protein that builds up in the tissues is called the A protein. AA amyloidosis is associated with some chronic diseases, such as diabetes, tuberculosis, rheumatoid arthritis, and inflammatory bowel disease. It may also be linked to aging. AA amyloidosis can affect the spleen, liver, kidneys, adrenal glands, and lymph n0odes. Lymph nodes are tiny, bean-shaped organs that fight infection.
  • Hereditary or familial amyloidosis – Hereditary amyloidosis is rare. It can be passed from generation to generation within a family. The proteins produced in hereditary amyloidosis may cause heart problems, carpal tunnel syndrome, and eye abnormalities.

Around 4,000 people develop AL amyloidosis each year in the United States. The disease is typically diagnosed between the ages of 55 to 65 years, although people as young as 20 years of age have also been diagnosed with AL amyloidosis. Hereditary and AA amyloidosis are less common than is AL amyloidosis.

Because amyloidosis is rare, the diagnosis is either delayed often or the condition is not diagnosed. The survival rate for AL amyloidosis depends on different factors, including how early it is diagnosed, if and how the heart is affected, and how well the treatment works.

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How Does Amyloidosis Affect Your Body?

Amyloid fibrils are protein polymers comprising identical monomer units (homopolymers). Functional amyloids play a beneficial role in a variety of physiologic processes (like long-term memory formation and gradual release of stored peptide hormones). Amyloidosis results from the accumulation of pathogenic amyloids, most of which are aggregates of misfolded proteins, in a variety of tissues.

What Are The Causes of Amyloidosis?

Amyloidosis arises due to protein misfolding. Hereditary amyloidosis results from genetic changes that cause the body to make abnormal proteins. Abnormal or misfolded protein depositions affect the functioning of the organs. Once amyloid deposits start, they seem to continue building up in the same locations. The heart, kidneys, nervous system, and GI tract are the most affected.

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What Are The Risk Factors of Amyloidosis?

Anyone can develop amyloidosis. Factors that increase its risk include:

  • Age – Most people diagnosed with AL amyloidosis are between 60 and 70 years of age, although earlier onset occurs.
  • Sex – Nearly 70 percent of people with AL amyloidosis are men.
  • Other diseases – Having a chronic infectious or inflammatory disease increases the risk of AA amyloidosis.
  • Family history – Some types of amyloidosis are hereditary.
  • Kidney dialysis – Dialysis can’t always remove large proteins from the blood. When on dialysis, abnormal proteins can build up in the blood and eventually be deposited in the tissue. This condition is less common with modern dialysis techniques.
  • Race – People of the African descent appear to be at higher risk of carrying a genetic mutation associated with the type of amyloidosis that can harm the heart.
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What Are The Symptoms of Amyloidosis?

Symptoms of amyloidosis are usually determined by the organ or function that is affected by the protein buildup.

  • Kidneys – Amyloidosis in the kidneys will reduce the kidneys’ ability to filter waste and break down proteins. As a result, large amounts of protein may be found in the urine, causing “foamy” urine. The kidneys may even stop working. Decreased urine output and changes in creatinine clearance tests, a blood test to measure kidney function, may be present.
  • Liver – Amyloidosis may cause the liver to grow larger and affect its ability to function normally. This may cause pain in the upper abdomen, swelling in the abdomen, and changes in liver enzymes that can be found using blood tests.
  • Heart – Amyloidosis of the heart may cause an irregular heartbeat (called an arrhythmia), enlargen the heart, and cause poor heart function. This will result in fluid buildup, an irregular heartbeat, shortness of breath, or chest pain.
  • Gastrointestinal tract – Amyloidosis of the gastrointestinal tract may cause problems with the digestion and absorption of food nutrients, diarrhea or constipation, bleeding, blockages, and a thickened tongue called macroglossia. It may also cause problems with the esophagus, including the gastroesophageal reflux disease (GERD).
  • Thyroid gland – Amyloidosis of the thyroid gland may cause goiter, a non-cancerous swelling of the thyroid gland.
  • Lungs – Amyloidosis of the lungs may cause problems with breathing, including shortness of breath.
  • Nervous system – Disorders of peripheral nerves are the most common neurological complications of amyloidosis. Patients may experience painful paresthesias (unusual sensations), numbness and balance difficulties, vomiting, diarrhea, constipation, sweating, or sexual problems. Numbness, tingling, or weakness in the arms or legs may develop. This condition is known as peripheral neuropathy. Carpal tunnel syndrome may also occur.

Other general symptoms of amyloidosis include:

  • Fatigue, which is extreme exhaustion or tiredness. It is a common problem for people with amyloidosis. Patients who feel fatigue often say that even a small effort, such as walking across a room, can seem like too much.
  • Unexplained weight loss
  • Anemia, which is a low level of red blood cells
  • Weak hand grip, which may arise from carpal tunnel syndrome
  • Skin changes, such as a rash around the eyes
  • Clay-colored stools
  • Joint pain
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How is Amyloidosis Diagnosed?

Amyloidosis can be diagnosed via the following methods :

  • Laboratory tests – Doctors may take samples of the patient’s blood and urine to run tests to learn more about the patient’s disease and general health.
  • Bone marrow aspiration and biopsy – Both these procedures are similar and often done at the same time to examine the bone marrow. A common site for bone marrow biopsy and aspiration is the posterior iliac crest i.e. a part of the pelvic bone located in the lower back. Bone marrow is the spongy tissue inside the bones. It has both a solid and a liquid part. A bone marrow aspiration removes a sample of the fluid with a needle. A bone marrow biopsy is the removal of a small amount of solid tissue using a needle. A pathologist then analyzes the sample(s).
  • Biopsy – A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that amyloid proteins are present, but only a biopsy can make a definite diagnosis. A pathologist then analyzes the sample(s). A pathologist is a doctor who specializes in interpreting laboratory tests and evaluating cells, tissues, and organs to diagnose disease. When amyloidosis is suspected, tissue samples are most often taken from abdominal fat or bone marrow (see below). A sample may also be taken from the liver, nerves, heart, kidneys, or rectum. However, these are more invasive procedures, and a patient may need to stay in the hospital for these tests.
  • Ultrasound – An ultrasound uses sound waves to create a picture of the internal organs. Areas affected by amyloid protein make different echoes of the sound waves than healthy tissue. When the sound waves bounce back to the computer and are changed into images, the doctor can find these areas inside the body. An ultrasound of the abdominal area may be used to look for enlarged organs.
  • Heart evaluation – A heart evaluation, including an electrocardiogram (EKG or ECG) and an echocardiogram (echo), will look for structural abnormalities in the heart and examine the motion of the walls of the heart.
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How to Prevent And Control Amyloidosis?

There is no known way of preventing Amyloidosis. It is an incurable disease, though treatment helps in managing symptoms of the disease.

Treatment of Amyloidosis

Several treatment methods are available for Amyloidosis.

  • Medications used to treat amyloidosis: Medication may be used to control the problems associated with amyloidosis. Steroids have been shown to work well, and they are typically combined with other drugs.
  • Patisiran (Onpattro)- This is the drug used for the treatment of polyneuropathy caused by hereditary transthyretin-mediated amyloidosis (hATTR) in adults. Patisiran acts by using RNA to interfere with the production of mutant transthyretin (TTR) protein, thereby reducing serum TTR protein levels and TTR protein deposits in tissues. It is administered by intravenous infusion every 3 weeks.
  • Immunomodulatory drugs – Drugs in this class include lenalidomide (Revlimid), pomalidomide (Pomalyst), and thalidomide (Synovir, Thalomid).
  • Monoclonal antibodies – A monoclonal antibody is a type of targeted therapy. It recognizes and attaches to a specific protein in the abnormal cells, and it does not affect cells that don’t have that protein. Drugs in this class include daratumumab (Darzalex) and elotuzumab (Empliciti). The second type of monoclonal antibody directly targets the amyloid itself. There are currently several of these antibodies in clinical trials.
  • Proteasome inhibitors – Proteasome inhibition is a type of targeted therapy. The drugs in this class target specific enzymes called proteasomes that digest proteins in the cells. This class includes bortezomib (Velcade), ixazomib (Ninlaro), and carfilzomib (Kyprolis).
  • Chemotherapy – Chemotherapy is the use of drugs to destroy abnormal cells, usually by stopping the cells’ ability to grow and divide. It is most commonly used to treat cancer. However, chemotherapy is also useful for other conditions, including amyloidosis. Chemotherapy may be given by a hematologist or a medical oncologist, a doctor who specializes in giving chemotherapy to treat cancer. During treatment for amyloidosis, chemotherapy is used to destroy abnormal cells in the blood. Common ways to give chemotherapy include an intravenous (IV) tube placed into a vein using a needle, a shot under the skin, or a pill or capsule that is swallowed (orally). A chemotherapy regimen (schedule) usually consists of a specific number of cycles given over a set period of time. A patient may receive 1 drug at a time or combinations of different drugs at the same time. Some of the common types of chemotherapy used to treat amyloidosis are cyclophosphamide (Cytoxan, Neosar) and melphalan (Alkeran) combined with dexamethasone (multiple brand names) and prednisone (multiple brand names).
  • Targeted therapy – Targeted therapy is a treatment that targets specific genes, proteins, or the tissue environment that contributes to the development of amyloidosis. This type of treatment blocks the growth and spread of abnormal cells while limiting damage to healthy cells. Recent studies show that not all abnormalities have the same targets. To find the most effective treatment, the doctor may run tests to identify genes, proteins, and other factors. This helps doctors match each patient better with the most effective treatment whenever possible. In addition, many research studies are taking place now to find out more about specific molecular targets and new treatments directed at them. For amyloidosis, targeted therapies include anti-angiogenesis therapy, monoclonal antibodies, and proteasome inhibitors.
  • Surgery – Surgery used to treat amyloidosis may include organ transplantation. Liver transplantation has been effective in treating certain types of hereditary amyloidosis. Kidney and heart transplantation may also work well. However, organ transplantation may not be appropriate for all patients, especially those who have large amounts of amyloid proteins that have been deposited in their organs.
  • Stem cell transplantation/bone marrow transplantation – A bone marrow/stem cell transplant is a medical procedure in which the plasma cells in the bone marrow that produce amyloid protein are first destroyed by high doses of chemotherapy and then replaced by highly specialized cells, called hematopoietic stem cells, that develop into the healthy bone marrow. Hematopoietic stem cells are blood-forming cells found both in the bloodstream and in the bone marrow. Today, this procedure is more commonly called a peripheral blood stem cell transplant, rather than bone marrow transplant, because it is the stem cells collected from the bloodstream that are typically being transplanted, not the actual bone marrow tissue.
  • β2-m–adsorbing columns – These columns have demonstrated some benefit in dialysis-related amyloidosis. This addition to long-term dialysis may reduce inflammation and accumulation of fibrils without major adverse effects.
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Amyloidosis – Lifestyle Tips

People treated for amyloidosis are encouraged to follow these guidelines for good health:

  • Maintaining a healthy weight
  • No smoking
  • Eating a balanced diet
  • Getting recommended screening tests from time to time
  • Moderate physical activity to help rebuild strength and energy levels

What Are The Recommended Exercises For a Person With Amyloidosis?

Amyloidosis can cause fatigue and weakness, so exercising may be difficult. Also, cardiac issues can make intense workouts out of the question. Running and other high-intensity exercises can be challenging with amyloidosis, but this doesn’t mean that one should stop moving completely. It’s best to stick with light or moderate-intensity exercises, such as:

  • Taichi
  • Yoga
  • Weight training
  • Walking programs

Amyloidosis And Pregnancy – Things to know

Pregnancy with amyloidosis is not common. Nevertheless, amyloidosis will complicate pregnancies with the underlying disease and may cause terrible perinatal morbidities and mortalities.

Common Complications Related to Amyloidosis

Complications of amyloidosis depend on the organs affected due to amyloid deposition:

  • Kidneys – Amyloid can harm the kidneys’ filtering system, causing the protein to leak from the blood into the urine. The kidneys’ ability to remove waste products from the body is lowered, which may eventually lead to kidney failure.
  • Heart – Amyloid reduces the heart’s ability to fill with blood between heartbeats. Less blood is pumped with each beat and shortness of breath may be experienced. If amyloidosis affects the heart’s electrical system, the heart’s rhythm may be disturbed.
  • Nervous system – Pain, numbness, tingling of the fingers, lack of feeling, or a burning sensation in the toes or the soles of the feet are experienced. Amyloid affects the nerves that control the bowel function. Periods of alternating constipation and diarrhea might be experienced too.
  • If the condition affects the nerves that control blood pressure, dizziness or near fainting when standing too quickly may be observed.

Other FAQs About Amyloidosis

Q. What is the life expectancy of patients with amyloidosis?

A. Recent years have seen important strides forward in the treatment and the outlook for patients diagnosed with amyloidosis today. In some types of amyloidosis, currently available treatments may even lead to a complete cure, while in others, there may be extended symptom-free survival. Twenty years ago the life expectancy of patients diagnosed with amyloidosis was usually only a few months or years, whereas now it is often 10 years or more.

Q. Is amyloidosis a form of cancer?

A. No. AL amyloidosis is related to a type of bone marrow cancer called multiple myeloma, and it is treated in a similar fashion with chemotherapy drugs and sometimes with stem cell transplantation. However, amyloidosis is not cancer.

Q. What are the side effects of chemotherapy for AL amyloidosis?

Intermediate and high dose chemotherapy is inevitably associated with at least some nausea, poor appetite, and tiredness. Temporary hair loss may occur. Vomiting during the chemotherapy can now largely be prevented.

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