patho 3...Q - maryam2009

[ArchivalUser]

48-year-old female presents with a chief complaint of shortness of
breath with exercise. Her past medical history is significant for
rheumatoid arthritis, for which she takes non-steroidal anti-inflammatory
agents. Physical examination is remarkable for slightly muffled heart
sounds and fine bilateral rales in her lungs. A chest x-ray reveals
cardiomegaly and evidence of mild pulmonary edema; an echocardiogram
demonstrates a reduced ejection fraction. Examination of a hematoxylin
and eosin-stained section of biopsy material from her right ventricle
reveals moderate amounts of a homogenous pink material infiltrating the
heart muscle. The pink material is most likely composed of which of the
following proteins?
A. AA amyloid protein
B. AE amyloid protein
C. AF amyloid protein
D. AL amyloid protein
E. Beta amyloid precursor protein

[ArchivalUser]

[ArchivalUser]

aa?? (chronic inflammatory dz).

[ArchivalUser]

A

[ArchivalUser]

The correct answer is A.

The symptoms described in this case are due to amyloidosis associated with rheumatoid arthritis. The amyloid protein has deposited in her heart and is causing symptoms of congestive heart failure. The term amyloid describes a variety of fibrillary proteins deposited in different tissues during pathologic circumstances. It stains pink with routine H and E stains, but shows apple-green birefringence when Congo red-stained material is viewed with polarized light. Type AA amyloid protein is an acute phase protein (MW 18,000) that is produced by the liver during inflammatory reactions such as chronic infections and rheumatoid arthritis.

AE amyloid protein (choice B) is a peptide hormone precursor that is usually associated with medullary carcinoma of the thyroid and pancreatic islet cell adenomas. The amyloid protein is not systemically distributed but instead is found locally within the neoplasm.

AF amyloid protein (choice C) is a pre-albumin protein. It is associated with certain familial amyloidosis syndromes, in which it is distributed within peripheral nerves and kidney. It is also associated with senile cardiac amyloidosis in the elderly, which affects individuals without any significant past medical history. Deposition is usually within a single organ.

AL amyloid (choice D) is a protein composed of immunoglobulin light chains. It is associated with myeloma and B cell malignant lymphomas. The neoplastic cells produce this protein, which deposits in the heart, GI tract, kidney, spleen and tongue.

Beta amyloid precursor protein (choice E), also known as A4 peptide, is a 4000D peptide associated with Alzheimer's disease and Down syndrome. It is derived from a serum protein encoded on chromosome 21. It appears in neurofibrillary tangles, plaques, and in the walls of cerebral vessels.

Remember:
AA, Acute phase reactant
AF, Familial and old fogies
AL, Light chain
AE, Endocrine