The generic term amyloidosis covers various diseases that are associated with deposits of tiny protein threads, known as protein fibrils, throughout the body. The body is unable to dissolve or break down these amyloids, which can lead to severe damage to various organs as the disease progresses. In particularly severe cases, not only individual organs but all organ systems are affected by the disease.
Further information and selected amyloidosis specialists can be found below.
There are three main forms of the disease. Light-chain (AL) amyloidosis is caused by diseases of the bone marrow. This leads to an increase in plasma cells, which are responsible for the production of antibodies. In addition to the intact antibodies, structurally altered free light chains always enter the blood. The body then deposits these in the organ structures. The proliferation of plasma cells is often based on a tumor of the lymphatic tissue. AL amyloidosis is therefore particularly common in multiple myeloma or Waldenström's disease. Both diseases are malignant blood diseases.
AA amyloidosis, on the other hand, is caused by chronic inflammatory diseases. The trigger here is the acute phase protein, which is increasingly formed in chronic infections such as tuberculosis or leprosy. Chronic inflammatory bowel diseases such as Crohn's disease or ulcerative colitis as well as rheumatic diseases can also trigger AA amyloidosis. Changes in the genetic material and mutations can cause hereditary or familial amyloidosis. This often occurs in combination with other inherited diseases such as familial Mediterranean fever.
The protein filaments can also accumulate in the kidneys and lead to functional disorders. The result is nephrotic syndrome with protein loss via the kidneys. This leads to water retention in the body and, with the loss of immunoglobulins, which are responsible for the body's defenses, to an increase in infections. Amyloidosis of the gastrointestinal tract mainly manifests itself through diarrhea, bleeding or intestinal blockages with severe pain. The liver is enlarged and feels as hard as a rock on palpation.
The brain and nerves can also be affected by the disease. This results in functional disorders of all kinds, which are similar in their effects to dementia. The protein filaments can also cause damage to the peripheral nerves, i.e. the nerves that lie outside the spinal cord and brain. Typical symptoms here are sensory and movement disorders. Carpal tunnel syndrome, nodular changes in the skin, hair loss, red circles under the eyes or hoarseness, on the other hand, are more likely to indicate an infestation of the soft tissue. In rare cases, amyloidosis causes disorders in the hormonal system, which manifest themselves as thyroid disorders or hypofunction of the adrenal glands.
The symptoms of amyloidosis are often non-specific and can also occur in other diseases. For this reason, the diagnosis is often only made at an advanced stage of the disease. However, amyloidosis is always suspected when patients suffer from cardiomyopathy, nerve dysfunction or liver enlargement of unknown cause. Likewise, amyloidosis should always be considered as a possible concomitant disease in patients with multiple myeloma .
To make a reliable diagnosis, the doctor must take a tissue sample from an affected organ and examine it in the laboratory. This reveals the exact composition of the protein filaments, which must be known for successful treatment. In the case of generalized amyloidosis, the sample can also be taken gently from the subcutaneous fatty tissue. If amyloidosis is confirmed by these examination procedures, bone marrow puncture is used to search for causative diseases.
The extent of the filamentous deposits is determined by scintigraphy. Patients are given radioactively labeled substances that bind to the protein filaments so that they become visible in the imaging procedure. However, diagnosis is often difficult, so that amyloidosis can often only be diagnosed after death at autopsy.
The majority of amyloidoses can be treated today. The therapy depends on the form of the disease. For example, the uncontrolled proliferation of plasma cells can usually be curbed by high-dose chemotherapy followed by stem cell transplantation .
Patients with Mediterranean fever can counteract the development of amyloidosis by taking the substance colchicine. In addition, the organ damage is treated with various general measures and medication. People with heart disease are given ACE inhibitors and diuretics to lower blood pressure. If the kidneys are involved, a low-salt diet may be useful.
