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- Amyloidosis is a condition in which
amyloids, i.e., protein fibrils (minute fibers) not normally
present in the body, become deposited in one or more sites,
damaging the organs where they collect. Virtually any organ
in the body may be affected. Symptoms are determined by the
location of the buildup, and vary from mild to severe and
life threatening.
- There are two forms of this
condition: primary and secondary. In primary amyloidosis
(called AL) the protein fibrils are made up of the light
chain portions of antibodies. Typical sites of fibril
pooling are the heart, lungs, skin, tongue, blood vessels,
kidney, liver, and thyroid gland. The cause of this form is
not known.
- In secondary amyloidosis (called
AA) fibrils are derived from acute phase reactant
apolipoprotein precursors (i.e., molecules that are signs of
infection in the body). Typical sites of collection are the
adrenals, lymph nodes, liver, spleen, and kidneys. In this
form of the disease, amyloidosis is secondary to another
disease.
- Still other protein fibril forms
exist, such as those associated with aging, heart disease,
and Alzheimer's.
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Directly
related to the organ affected. Examples below:
- Heart -- congestive Heart Failure (shortness of breath, leg swelling, crackles on lung exam, Heart Failure on chest X-Ray)
- Respiratory system -- cough,
shortness of breath, sinus problems
- Kidney -- protein in the urine, water retention (edema), elevated BUN and Creatinine
- Liver -- enlarged liver, mild
elevation in liver function tests
- Gastrointestinal tract -- obstructive symptoms (nausea, vomiting, abdominal distention, Constipation), blood in bowel movements, weight loss, malabsorption (greasy stools), and Malnutrition
- Nervous system -- peripheral Neuropathy (pain, numbness, weakness, or loss of sensation, especially in legs and feet), hoarseness, postural Hypotension (blood pressure drops on standing, causing lightheadedness or fainting), inability to sweat, inability to control bladder or bowels. Carpal Tunnel Syndrome may also occur. Senile plaques and
neurofibrillary tangles in the brain may occur. The
cranial nerves are usually not affected.
- Endocrine -- may infiltrate
endocrine glands such as the thyroid, but rarely causes a
problem in function
- Joints -- can infiltrate joints
and cause pain and stiffness (i.e., symptoms of
arthritis)
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- Abdominal subcutaneous fat pad
biopsy and rectal biopsies are good first places to test
(with appropriate staining techniques) if the diagnosis is
suspected. Other areas of high yield are the gingiva (gums)
and bone marrow.
- If the above techniques fail or
cannot be performed, tissue from the affected organ must be
biopsied and examined using the specified
stains.
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- None specifically for amyloidosis
- Treat the underlying disease (e.g., Multiple Myeloma) or
specific manifestations (e.g., hemodialysis for renal
amyloid)
- Surgical excision of amyloid tumors
- Unfortunately, systemic forms (i.e., affecting many
organs in the body) slowly progress and death often occurs
in 1-3 years.
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Classification System
(Protein fibril type is in
parenthesis.)
- Primary (AL) -- no other
condition present
- Amyloidosis associated with Multiple Myeloma
(AL)
- Secondary or reactive amyloidosis associated with chronic infections (e.g., Tuberculosis) or chronic diseases (e.g., Rheumatoid Arthritis)
(AA)
- Heredofamilial amyloidosis --
neuropathic, cardiovascular, renal, and others, plus those
associated with Mediterranean fever (AA). This is a
genetically transmitted form of amyloidosis.
- Local amyloidosis -- tumorlike
deposits in isolated organs
- Amyloidosis associated with
aging
- Amyloidosis associated with hemodialysis (kidney dialysis)
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