Amyloid Flashcards
Amyloid
Misfolded protein deposits in extracellular space → Damaged Tissues
Common characteristics of various proteins that can deposit as amyloid
β-pleated sheet configuration
Congo red staining
Apple green birefringence under polarized light
Where does amyloid tend to deposit?
Can be systemic or localized, but tends to be peri-vascular
Systemic Amyloidosis (Primary)
Systemic Deposition of AL Amyloid
Derived from Ig light chain
Associated with plasma cell dyscrasias (overproduction of light chain)
Systemic Amyloidosis (Secondary)
Systemic Deposition of AA Amyloid (Derived from SAA, an acute-phase reactant)
Increased in:
Chronic inflammatory states
Malignancy
Familial Mediterranean Fever
Familial Mediterranean Fever
Autosomal Recessive PMN Dysfunction
Patients of Mediterranean Origin
Episodes of fever & acute serosal inflammation
High SAA during attacks (leads to AA Amyloid deposition)
Familial Mediterranean Fever can masquerade as
MI
Appendicitis
Inflammation of anything else with a serosal surface
Classic Clinical Findings of Amyloid
Nephrotic Syndrome (Kidney is most commonly involved organ)
Restrictive Cardiomyopathy (wall compliance ↓ due to amyloid stiffness, filling ↓)
Arrhythmia
Tongue Enlargement
Bowel Wall Thickening → Malabsorption, Hepatosplenomegaly
Diagnosis of Amyloid
Biopsy: Apple green birefringence, congo red stain)
Easy Targets: Abdominal Fat Pad Aspiration, Rectum
Treatment for Amyloid Organ Damage
Transplant (Amyloid can’t be removed)
Localized Amyloidosis
Senile Cardiac Amyloidosis Familial Amyloid Cardiomyopathy NIDDM (Type II) Alzheimer's Disease Dialysis-Associated Amyloid via Medullary Carcinoma of the Thyroid
Senile Cardiac Amyloidosis
Elderly patient
Non-Mutated Serum Transthyretin deposition in the heart
Asymptomatic, present in 25% of individuals > 80
Familial Amyloid Cardiomyopathy
Mutated Serum Transthyretin in the heart
Restrictive cardiomyopathy
5% of African American patients carry the gene
Amyloid NIDDM (Type II)
Amylin (byproduct of insulin) deposits in pancreatic islets, leads to insulin resistance
Serum Transthyretin
2nd most common protein in the blood
