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Amyloidosis |
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Definition
Amyloidosis is a progressive, incurable, metabolic
disease characterized by abnormal deposits of
protein in one or more organs or body systems.
Causes
Doctors classify amyloidosis into three major forms:
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Primary amyloidosis. This most
common form of amyloidosis primarily affects your
heart, kidneys, tongue, nerves and intestines.
Primary amyloidosis isn't associated with other
diseases except for multiple myeloma, in a
minority of cases.
The cause of primary amyloidosis is unknown, but
doctors do know that the disease begins in your
bone marrow. In addition to producing red and
white blood cells and platelets, your bone marrow
makes antibodies — proteins that protect you
against infection and disease. After antibodies
serve their function, your body breaks them down
and recycles them. Amyloidosis occurs when cells
in the bone marrow produce antibodies that can't
be broken down. These antibodies then build up in
your bloodstream. Ultimately, they leave your
bloodstream and can deposit in your tissues as
amyloid, interfering with normal function.
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Secondary amyloidosis. This form
occurs in association with chronic infectious or
inflammatory diseases, such as tuberculosis,
rheumatoid arthritis or osteomyelitis, a bone
infection. It primarily affects your kidneys,
spleen, liver and lymph nodes, though other organs
may be involved. Treatment of the underlying
disease may help stop this form of amyloidosis.
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Hereditary amyloidosis. As the
name implies, this form of amyloidosis is
inherited. This type often affects the nerves,
heart and kidneys.
Symptoms
Signs and symptoms of amyloidosis depend on the
organs affected. The wide range of signs and
symptoms often makes amyloidosis difficult to
diagnose. You may even have no symptoms. Signs and
symptoms may include:
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Swelling of your ankles and legs
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Weakness
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Weight loss
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Shortness of breath
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Numbness or tingling in your hands or feet
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Diarrhea
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Severe fatigue
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An enlarged tongue (macroglossia)
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Skin changes
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An irregular heartbeat
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Difficulty swallowing
Screening and Diagnostics
Blood and urine tests can reveal the presence of
amyloid protein, but tissue or bone-marrow biopsy is
necessary to positively diagnose amyloidosis. Once
the diagnosis has been confirmed, additional
laboratory tests and imaging procedures are
performed to determine:
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which type of amyloid protein is involved
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which organ(s) or system(s) have been affected
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how far the disease has progressed
Treatment
Some patients with primary amyloidosis respond to
chemotherapy directed at the abnormal plasma cells.
Autologous stem cell transplantation may be used, as
in multiple myeloma.
In secondary amyloidosis, aggressive treatment of
the underlying disease can improve symptoms and/or
slow progression of disease. Complications such as
heart failure, kidney failure, and other problems
can sometimes be treated as necessary. |
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