Amyloidosis Question And Answers

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Amyloidosis Important Notes

1. Congo red stain

  • All amyloid types have an affinity for it
  • It stains amyloid orange in colour and when viewed in polarized light shows apple green birefringence

2. Primary and secondary amyloidosis

  • Primary amyloidosis
    • Most common form
    • Occurs most commonly in plasma cell dyscrasias
    • It occurs in the heart, skin and skeletal muscle
  • Secondary amyloidosis
    • Occurs as a complication of chronic infection or non-infectious inflammatory conditions
    • Typically distributed in the kidney, liver, spleen and adrenals

3. Amyloidosis of the kidney

  • The most common and most serious
  • Affected kidneys may be normal-sized or enlarged
  • The cut surface shows a pale, waxy and translucent appearance

4. Diagnosis of amyloidosis

  • Biopsy
  • FNAC of abdominal subcutaneous fat followed by Congo red staining
  • Injection of congo red dye intravenously in a living patient
  • Electrophoresis
  • Bone marrow aspiration

Amyloidosis Long Essays

Question 1. Define amyloidosis. Discuss in detail the etiopathogenesis of amyloidosis. Add a note on its staining characteristics.
Answer:

Definition:

  • Is the term used for a group of diseases characterised by extracellular deposition of fibrillar proteinaceous sub-stance called amyloid having a common morphological appearance, staining properties and physical structure but with variable protein composition.

Pathogenesis:

  • Irrespective of the type of amyloid, amyloidogenesis in vivo, occurs in the following sequence.
    • The pool of amyloidogenic precursor protein is present in circulation or may be present in response to stimuli.
    • A nidus of fibrillogenesis is formed which stimulates the deposition of amyloid protein
    • Partial degradation or proteolysis occurs before the deposition of fibrillar protein

Staining characteristics of Amyloid:

Amyloidosis Staining characteristics of Amyloid

Amyloidosis Short Essays

Question 1. Classification of amyloidosis
Answer:

1. Based on the cause:

  • Primary – with unknown cause and deposition is in the disease itself.
  • Secondary – As a complication of some underlying known disease.

2. Based on the extent of amyloid deposition:

  • Syssniic (generalised) – Involving multiple organs.
  • Localised – involving one/2 organs.

3. On histological basis:

  • Peri collagenous-corresponding in distribution to primary amyloidosis.
  • Perirectulin – corresponding in distribution to sec­ondary amyloidosis.

Read And Learn More: Pathology Question And Answers

4. Based on tissues:

  • Mesenchymal – organs derived from mesoderm.
  • Parenchymal – GFgafiS ueFiveu fFGfil ectoderm and

5. Clinicopathologic classification:

  • Systemic (generalised) amyloidosis:
    • Primary (AL)
    • Secondary/reactive/inflammatory (AA)
    • Heradofamilial (ATTR, AA, others)
  • Localised amyloidosis:
    • Senile cardiac (ATTR)
    • Senile cerebral (AB, APP)
    • Endocrine (hormone precursors)
    • Tumour forming (AL)

Question 2. Microscopy of sago spleen
Answer:

  • Sago’s spleen is a form of amyloidosis of the spleen
  • In it splenomegaly is not marked
  • The cut surface shows translucent, pale and waxy nodules resembling sago grains
  • Microscopically it shows amyloid deposits in the walls of arterioles of the white pulp
  • Later these deposits replace follicles

Question 3. Pathological changes in amyloidosis
Answer:

Gross Changes:

  • The organ is usually enlarged, pale and rubbery

Cut Surface:

  • It shows firm, translucent and waxy parenchyma

Microscopic Changes:

  • Amyloid deposits are found in the walls of small blood vessels
  • Later these deposits produce large macroscopic changes in the blood vessels
  • Produces pressure atrophy

Amyloidosis Short Question And Answers

Question 1. Amyloidosis of liver
Answer:

It occurs in about half of the cases of systemic amyloidosis

Amyloidosis of Liver Pathology:

1. Gross features

  • Liver is
    • Enlarged
    • Pale
    • Waxy
    • Firm

2. Microscopic features

  • Initially
    • Amyloid appears in the space of Disse
  • Later
    • Deposits increase
    • It compresses cords of hepatocytes
    • Liver cells get shrunken
    • They become atrophic and are replaced by amyloid
    • Hepatic function is normal
  • Portal tracts and Kupffer cells are involved rarely.

Question 2. Source and nature of amyloid
Answer:

Amyloid is composed of 2 main types of complex proteins:

1. Comprises about 95% of amyloid.

  • Comprises about 95% of amyloid.
  • This consists of a meshwork of fibril proteins which are delicate, randomly dispersed, non-branching and having an indefinite length.
  • Chemically 2 major types of amyloid proteins were identified.
    • AL (Amyloid light chain) protein.
    • AA (Amyloid-associated) protein.
    • Other proteins which include Transthyretin
      • β-Amyloid protein.
      • Ap2 microglobulin.
      • Amyloid from hormone precursor proteins.
      • Immunoglobulin heavy chain amyloid (AH)

2. Non-fibrillae components.

  • Comprises of about 5% of amyloid material.
  • These include the amyloid P (AP) component
    • Aglipoprotein – E (apoE)
    • Sulphated glycosaminoglycans
    • α – 1 anti chymotrypsin
    • Protein X

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