A/13 Flashcards
Cause of amyloidosis
inherited, inflammatory, neoplastic diseases cause aggregation of misfolded proteins
What is the stain used to see amyloidosis?
congo red staining : birefringence
Where do the amyloids deposit?
in the interstitial spaces
How do the proteins aggregate to form amyloids?
When they misfold they expose more beta-sheets. These sheets easily stack to form crossed beta plates
What are the 4 types of amyloid?
- amyloid light chain (AL) : primary
- amyloid associated (AA) : secondary
- amyloid beta (Ab)
- transthyretin (ATTR)
Which amyloid type is localized and not systemic?
amyloid beta
What is AL made of?
Misfolded proteins made of Ig light chains or fragments of it, produced by neoplastic plasma cells
What an be the cause of AL?
Myeloma (cancer)
What is AA made of?
Aggregate of SAA proteins (serum amyloid A)
When is SAA produced and where?
In the liver in increased inflammatory states
What is SAA associated with usually?
long standing inflammation (TB, autoimmune disorders)
When can we see Ab?
In cerebral lesion of alzheimer’s disease
What is Ab made of?
from APP (amyloid precursor protein)
What is ATTR made of?
TTR protein : transthyretin
When do we see ATTR?
In senile systemic amyloidosis
Morphology of amyloidosis?
- organomegaly
- pressure atrophy of cells
- brown color on surface using iodine and sulphuric acid
Organs most affected by amyloidosis (5)
- kidney
- spleen
- liver
- heart
- GI (gingiva)
Where does amyloid deposit in kidney? (4)
glomeruli, mesangium peritubular interstitium, walls of vessels
Amyloid patterns in spleen (2)
- sago spleen : in follicles
- in sinuses and pulp
Morphology of liver affected by amyloid
- massively enlarged
- pale, waxy, grayish surface
Where does amyloid spread in liver?
dissl spaces, surrounds parenchyma cells
Morphology of amyloid in heart (2)
- dew-drop like subendocardial elevation
- deposit between myofibers (atrophy)
Non specific clinical manifestations of amyloid
weakness, fatigue, weightloss
Renal manifestation of amyloid
proteinuria, renal failure
Cardiac manifestation of amyloid
restrictive cardiomyopathy
