PATH - Amyloidosis Flashcards
Amyloidosis
Abnormal aggregation of proteins(or their fragments) into β-pleated linear sheets–>damage and apoptosis
Amyloid deposits visualized by Congo red stain, polarized light (apple green
birefringence), and H&E stain (shows deposits in glomerular mesangial areas,
tubular basement membranes)
AL (primary) amyloidosis
Due to deposition of proteins from Ig *Light chains
Can occur as a *plasma cell disorder or associated with *multiple myeloma.
Often affects *multiple organ systems, including renal
(nephrotic syndrome), cardiac (restrictive cardiomyopathy, arrhythmia), hematologic (easy bruising, splenomegaly), GI (hepatomegaly), and neurologic (neuropathy).
AA (secondary) amyloidosis
Seen with chronic inflammatory conditions such as *rheumatoid arthritis, IBD,
spondyloarthropathy, familial Mediterranean fever, protracted infection.
Fibrils composed of
serum *Amyloid *A.
Often multisystem like AL amyloidosis.
Dialysis-related amyloidosis
Fibrils composed of *β2-microglobulin in patients with *ESRD and/or on long-term dialysis
May present as *carpal tunnel syndrome
Heritable amyloidosis
Heterogeneous group of disorders, including *familial amyloid polyneuropathies due to *transthyretin gene mutation.
Age-related (senile) systemic amyloidosis
Due to deposition of normal (wild-type) *transthyretin (TTR) predominantly in *cardiac ventricles
Slower progression of cardiac dysfunction relative to AL amyloidosis.
Organ-specific amyloidosis
Amyloid deposition localized to a single organ
Most important form is amyloidosis in *Alzheimer
disease due to deposition of *β-amyloid protein cleaved from *amyloid precursor protein (APP)
*Islet amyloid polypeptide (IAPP) is commonly seen in *diabetes mellitus type 2 and is caused by deposition of amylin in pancreatic islets.
Isolated *atrial amyloidosis due to *atrial natriuretic peptide is common in normal aging.
