Amyloidosis

Question 1

APrP amyloid

Answer 1

Derived from prion proteins (spongiform encephalopathies such as Creutzfeldt-Jakob and Mad Cow)

Question 2

ACal amyloid

Answer 2

Derived from procalcitonin, found in medullary carcinoma of thyroid (from thyroid C cells)

Question 3

What is a classic feature of amyloidosis?

Answer 3

Glossomegaly

Question 4

What blood disorder may develop as a result of amyloidosis and why?

Answer 4

Coagulopathy, because of selective absorption of factor X by amyloid protein

Question 5

Amyloid consists of what two components?

Answer 5

Amyloid P (a component of normal basement membranes) and a disease-specific fibrillogenic protein

Question 6

How do amyloid deposits appear histologically?

Answer 6

Amorphous, acellular, eosinophilic, extracellular deposits

Question 7

What stain is used to detect amyloid and what do they look like under polarized light?

Answer 7

Congo red makes them red-orange, and they have an apple green birefringence under polarized light

Question 8

What stain causes auto-fluorescence of amyloid when viewed with ultraviolet light?

Answer 8

Thioflavin T

Question 9

What tertiary structure is common to all forms of amyloid?

Answer 9

Beta-pleated sheet

Question 10

Where is amyloid typically deposited first?

Answer 10

Around subendothelial basement membranes

Question 11

How do organs with significant amyloid appear grossly?

Answer 11

Pale and firm (due to lack of circulation)

Question 12

What are the categories in the old scheme of amyloidosis classification?

Answer 12

Primary, secondary, familial, and isolated

Question 13

Why is primary amyloidosis called primary and what is it associated with?

Answer 13

Associated with plasma cell disorder, symptoms related to amyloid deposition occur prior to diagnosis of plasma cell disorder

Question 14

Why is secondary amyloidosis called secondary and what is it associated with?

Answer 14

Associated with persistent inflammatory disorder (eg rheumatoid arthritis), which is diagnosed before the amyloidosis

Question 15

Familial Mediterranean fever

Answer 15

Autosomal recessive amyloidosis characterized by neutrophil disfunction (yields recurrent infections and secondary amyloidosis)

Question 16

Familial amyloidotic polyneuropathy

Answer 16

Autosomal dominant amyloidosis caused by point mutations in transthyretin gene (yields pierpheral and autonomic neuropathies)

Question 17

Why do Down syndrome patients tend to get early onset Alzheimer?

Answer 17

Because the gene for amyloid b protein precursor is located on chromosome 21

Question 18

What composes amyloid deposits in arteries and what is this fragment cleaved from?

Answer 18

Lactadherin, which is cleaved from medin

Question 19

Which amyloidosis is related to type 2 diabetes?

Answer 19

Amylin, which is islet amyloid polypeptide (oversynthesized by B islet cells in type 2 diabetics)

Question 20

Senile cardiac amyloidosis

Answer 20

A typically asymptomatic form of cardiac amyloidosis (composed of transthyretin) seen in older men

Question 21

AL amyloid

Answer 21

Derived from immunoglobulin light chains (esp lambda) and seen with plasma cell disorders and b-cell lymphomas (primary amyloidosis)

Question 22

AA amyloid

Answer 22

Derived from serum amyloid A (acute phase reactant), seen in inflammatory states (secondary amyloidosis)

Question 23

AB2M amyloid

Answer 23

Derived from B2-microglobulin (renal failure), leads to destructive arthropathy in dialysis pts

Question 24

AB amyloid

Answer 24

Derived from B protein (Alzheimer)