Amyloidosis is a term for disorder by which the various organs start to accumulate a protein called amyloid, a compound that our body is not able to degrade. There are large number of types of these amyloid proteins. Amyloidosis can be a hereditary condition which is a very rare situation but this article is focused on acquired amyloidosis (not-inherited but developed during person’s life because of another disease).
Congenital amyloidosis is caused by a genetic mutation that results in a molecular change in any of human organism's own proteins which looses the ability to be degraded and begins to accumulate in the body.
Acquired amyloidosis can be divided into two basic groups according to its cause:
Primary amyloidosis (AL amyloidosis)
Although the term "primary" could give a false impression that this form of amyloidosis occurs somehow by itself, it is not true. AL amyloidosis is a complication of cancer disease of blood cells, which is known as multiple meyloma. The essence of this disease is development of cancer white blood cells that create a large number of defective and poorly functional antibodies. Antibodies are protein compounds and their fragments become the basis of amyloid substance.
Secondary amyloidosis (AA amyloidosis)
Secondary Amyloidosis may accompany any chronic inflammatory disease. Every inflammation process in our body produces a wide spectrum of proteins that are known as acute phase proteins. In chronic inflammatory conditions the levels of these proteins increase steadily and some of them may begin to accumulate and store as amyloid compounds. AA amyloidosis may accompany autoimmune diseases such as rheumatoid arthritis, Crohn's disease, Bechterew's disease, ulcerative colitis and many others.
Note: There is a disease that is associated with only local production of amyloid. It is the Alzheimer's disease where amyloid forms in affected person’s brain and destroys its nerve cells.
Manifestation of the disease can be very variable and it depends on location of amyloid deposits. The symptoms are associated with impaired function of such tissues or organs. Heart amyloidosis is quite often that can be associated with cardiac arrhythmias and symptoms of heart failure. By accumulation of amyloid in the shortness of breath and coughing up blood may occur. The digestive tract may also be involved and in such case there emerge conditions like nausea, vomiting, diarrhea and blood in stool that may be accompanied by impaired absorption of nutrients. Damage to the nerves is associated with amyloid polyneuropathy symptoms. Hepatic or renal failure may be a serious complication. By amyloid deposition in the tongue it can become enlarged (macroglossia), it is the same in case of spleen or liver.
In case of amyloidosis suspicion it is necessary to obtain a sample of tissue and histologically confirm amyloid presence. Typically a sample rectal mucosa is obtained. This sample is histologically processed and examined under a microscope. Amyloid deposit is well seen when dyed using Congo red stain. After confiriming amyloid presence it is necessary to look for the certain amyloid protein type and for its underlying cause.
There is no curative therapy of amyloidosis alone; already formed and deposited amyloid can not be removed from human body). Therefore our primary target is the causative disease that we try to cure (chemotherapy for multiple myeloma, anti-inflammatory drugs against chronic inflammatory diseases etc.). Especially the prognosis of patients with AL amyloidosis is relatively poor and often leads to death within few years.