Amyloidosis

DESCRIPTION
* 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.

SYMPTOMS
* Directly related to the organ affected. Examples below:

1. Heart -- congestive Heart Failure (shortness of breath, leg swelling, crackles on lung exam, Heart Failure on chest X-Ray)
2. Respiratory system -- cough, shortness of breath, sinus problems
3. Kidney -- protein in the urine, water retention (edema), elevated BUN and Creatinine
4. Liver -- enlarged liver, mild elevation in liver function tests
5. Gastrointestinal tract -- obstructive symptoms (nausea, vomiting, abdominal distention, Constipation), blood in bowel movements, weight loss, malabsorption (greasy stools), and Malnutrition
6. 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.
7. Endocrine -- may infiltrate endocrine glands such as the thyroid, but rarely causes a problem in function
8. Joints -- can infiltrate joints and cause pain and stiffness (i.e., symptoms of arthritis)

HOW THE DIAGNOSIS IS MADE
* 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.

TREATMENT
* 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.

MISCELLANEOUS
* Classification System
(Protein fibril type is in parenthesis.)

1. Primary (AL) -- no other condition present
2. Amyloidosis associated with Multiple Myeloma (AL)
3. Secondary or reactive amyloidosis associated with chronic infections (e.g., Tuberculosis) or chronic diseases (e.g., Rheumatoid Arthritis) (AA)
4. Heredofamilial amyloidosis -- neuropathic, cardiovascular, renal, and others, plus those associated with Mediterranean fever (AA). This is a genetically transmitted form of amyloidosis.
5. Local amyloidosis -- tumorlike deposits in isolated organs
6. Amyloidosis associated with aging
7. Amyloidosis associated with hemodialysis (kidney dialysis)