Amyloidosis Flashcards
What is amyloid?
- Misfolded protein that deposits in extracellular space
- Damages tissues
What kind of protein is amyloid?
Beta-pleated sheet configuration
- Multiple proteins can be referred to as amyloid although they are all deposited in a particular way
How does amyloid stain?
- Congo red staining
- Apple-green birefringence under polarized light
Where does amyloid commonly deposit?
Around blood vessels
How can systemic amyloidosis be divided?
Into primary and secondary types
What protein is deposited in primary amyloidosis?
AL amyloid
What is AL amyloid derived from?
Ig light chain
What is primary amyloidosis associated with?
Plasma cell dyscrasias
- Overproduced light chain leaks out into blood, can become misfolded and deposit within tissue
Where are the light chains located in relation to the heavy chains?
Outside
What protein is deposited in secondary amyloidosis?
AA amyloid
What is AA amyloid (secondary amyloidosis) derived from?
SAA
What is SAA?
What is it increased in? (what diseases/states)
SAA is an acute phase reactant and a family of apolipoproteins associated with high-density lipoprotein (HDL) in plasma
- Chronic inflammatory states (lupus, rheumatoid, crohn’s)
- Malignancy
- Familial Mediterranean fever
What is familial Mediterranean fever?
How does it present?
- Dysfunction of neutrophils
- Presents with episodes of fever and acute serosal inflammation (appendicitis, pleuritis, pericarditis)
What kind of amyloidosis does Familial Mediterranean fever present with?
Secondary amyloidosis
- High SAA during attacks deposits as AA amyloid
How is Familial Mediterranean fever inherited?
Aut Recessive
What are the classic clinical findings in amyloidosis?
- Nephrotic syndrome
- Restrictive cardiomyopathy or arrhythmia
- Tongue enlargement
- Malabsorption
- Hepatosplenomegaly
How is amyloidosis diagnosed?
Tissue biopsy
- Usually abdominal fat pad and rectum are easily accessible targets
How are organs treated in amyloidosis?
Transpalnt
- Amyloid cannot be removed
What is localised amyloidosis?
Amyloid deposition in a single organ
What is the most common form of localised amyloidosis?
Senile cardiac amyloidosis
What percentage of individuals > 80 years old have senile cardiac amyloidosis?
25%
What is senile cardiac amyloidosis?
What protein is deposited in the heart?
Non-mutated serum transthyretin deposits in heart
- Usually asymptomatic
What protein deposits in the heart in familial amyloid cardiomyopathy?
Mutated serum tranthyretin
What kind of cardiomyopathy is caused by familial amyloid cardiomyopathy?
Restrictive cardiomyopathy
What percentage of african americans carry the mutated gene that leads to familial amyloid cardiomyopathy?
Restrictive
What deposits in the islets in the pancreas in T2 DM?
What is this protein derived from?
Amylin (derived from insulin)
What protein depositis in the brain in Alzheimer disease?
ABeta amyloid deposits in the brain, forming amyloid plaques
What is ABeta amyloid derived from?
What chromosome?
Beta-amyloid precursor protein (on chromosome 21)
What protein deposits in joints in dialysis-associated amyloidosis?
Beta2-microglobulin
- Not filtered well from blood
What protein deposits in medullary carcinoma of the thyroid?
Medullary carcinoma of the thyroid
What cells produce calcitonin?
C-cells
