AA amyloidosis is a systemic disease, meaning that any organs and tissues of the body can be affected by the amyloid deposition.
The most common organs involved in AA Amyloidosis are:
- Kidneys Nephrotic syndrome are the most common organs involved.
- Gastrointestinal tract.
The heart and the peripheral and autonomic nervous systems are rarely involved in AA amyloidosis.
Symptoms may be non-specific at first and are often complicated by the symptoms from the underlying inflammatory disease.
The most common symptoms and signs are:
- Protein in the urine.
- Swollen ankles and legs
- Weight loss.
- A feeling of bloating.
- Kidney failure.
If a patient presents with protein in the urine and a long standing chronic disease AA amyloidosis may be thought of before any tests are run. However, AA amyloidosis can only be definitively diagnosed through a tissue or organ biopsy, usually the kidney.
- A tissue biopsy involves taking a small piece of tissue which, if AA amyloidosis is suspected, may be taken from the kidney.
- This biopsy is stained with a dye called Congo red in the laboratory.
- If amyloid is present, the biopsy will appear red under normal light and green (apple-green birefringence) under special polarized light
2nd procedure in the laboratory
- Further testing is done on the biopsy to identify the type of amyloidosis by identifying the protein composition of the amyloid fibrils.
- It is imperative to identify the “type” as treatment is different for each type of amyloid.
A number of tests will be run in conjunction with the biopsy to help with the diagnosis, to assess organ damage and plan treatment.
- Blood tests, particularly kidney tests, albumin and cardiac biomarkers.
- Urine test to measure protein.
- Blood proteins to measure Serum Amyloid A (SAA) and CRP (C-reactive protein).
- ECG and Echocardiogram.
- History of any previous inflammatory diseases or infections.