The cause for amyloid to be produced and to collect in the tissues is not known. The risk of getting amyloidosis is not known to be connected to what a person eats (including how much protein) or does for a living. The risk of developing amyloidosis is greater in people who:
- Are older than 50
- Have a chronic infection or inflammatory disease
- Have a family history of amyloidosis
- Have multiple myeloma. Between 10 and 15% of people who have multiple myeloma develop amyloidosis.
- Have a kidney disease that has required dialysis for more than five years
Symptoms vary widely from person to person and depending on which organs are affected. Some people do not even have symptoms, which makes the condition difficult to diagnose. When amyloidosis is associated with another disease, symptoms may be masked.
Symptoms can include:
- General - Fatigue, loss of weight, weakness
- Cardiac - Shortness of breath, dizziness or feeling faint, exercise intolerance, irregular heart rate, palpitations
- Neurologic - Numbness or tingling in the hands or feet, painful feet/legs; carpal tunnel syndrome, which causes pain, numbness or tingling in the fingers. Approximately four out of 10 people with amyloidosis develop this syndrome.
- Gastrointestinal - Diarrhea alternating with constipation, abdominal cramps, early satiety, nausea and vomiting
- Kidney - Foam in urine, swelling of the ankles and legs
- Mouth and throat - Macroglossia (enlarged tongue), difficulty swallowing, hoarse voice
- Skin – Bruises easily particularly around the eyes
The severity of amyloidosis depends on which organs it affects. It can be life threatening if it causes kidney or heart failure.
If the amyloidosis affects the kidneys, their ability to filter the blood becomes impaired. Protein leaks from the blood into the urine. The loss of protein from the blood can cause fluid to leak out of the blood vessels, resulting in swelling in the feet, ankles and calves. Eventually, there is so much damage to the kidneys that they are not able to remove waste products from the body and they fail.
If amyloidosis affects the heart, the first symptom typically is shortness of breath even with only light activity. Climbing a flight of stairs or walking long distances may be difficult without having to stop. The buildup of amyloid in the heart lessens its ability to fill up with blood between heartbeats. As a result, less blood is pumped with each beat, and the heart is not able to keep up with the body's needs. The buildup of amyloid can also cause problems with the electrical system of the heart, resulting in irregular heartbeats (arrhythmia).