Amyloidosis | Anatomy2Medicine
Amyloidosis Symptoms

Amyloidosis

 

  • Amyloidosis

 

    • group of disorders is characterized by the deposition of amyloid

 

  • Amyloid

 

      • a proteinaceous material with certain physicochemical features.

 

  • Amyloid is not a single substance but a group of substances that share a common physical structure that can be formed by a number of different proteins

 

      • amyloidosis is identified as  disorder of abnormal protein folding.(MCQ)

 

  • other protein folding defect disorders
  • Alzheimer disease, Huntington disease
  • Parkinson disease
  • prion diseases, such as “mad cow” disease.

 

      • It always has a β-pleated sheet configuration (demonstrable by x-ray diffraction). .(MCQ)
      • Amyloid is characteristically extracellular in distribution.(MCQ)
      • Appears most often as accumulations proximate to basement membranes.

 

  • It has an amorphous eosinophilic appearance in routine hematoxylin and eosin sections. .(MCQ)

 

      • It is characteristically stained by Congo red dye.(MCQ)
      • demonstrates apple green birefringence when viewed under polarized light and confirming the suspected presence of amyloid. .(MCQ)

 

  • Primary amyloidosis (immunocytic dyscrasia amyloidosis)
  • The cause is deposition of amyloid fibrils derived from immunoglobulin light chains, referred to as AL (amyloid light chain) protein. .(MCQ)

 

      • Amyloid deposition in tissues of mesodermal origin, such as heart, muscle, and tongue is characteristic. .(MCQ)
      • It may involve the kidney, with amyloid deposits in the glomerular mesangium as well as in the interstitial tissue between tubules. .(MCQ)

 

  • Primary amyloidosis is the form frequently associated with  plasma cell disorders, such as multiple myeloma, Waldenström macroglobulinemia.(MCQ)

 

    • Secondary amyloidosis (reactive systemic amyloidosis)

 

  • Deposition of fibrils consisting of the amyloid protein called AA protein is characteristic.

 

      • AA protein is formed from a precursor, serum amyloid-associated protein (SAA)

 

  • Chronic tissue destruction leads to increased SAA.

 

      • Usually, involvement of parenchymatous organs, especially the kidney (nephrotic syndrome is very common), liver, adrenals, pancreas, lymph nodes, and spleen is seen.(MCQ)
      • Perifollicular involvement in the spleen results in “sago spleen,” an appearance reminiscent of tapioca-like granules. .(MCQ)
      • Secondary amyloidosis characteristically is a complication of chronic inflammatory disease, such as rheumatoid arthritis, tuberculosis, osteomyelitis, syphilis, or leprosy. .(MCQ)

 

  • It also may complicate noninflammatory disorders, such as renal cell carcinoma and Hodgkin disease. .(MCQ)

 

    • Portuguese type of polyneuropathy
      • associated with an amyloid derived from a protein known as transthyretin (a serum protein that transports thyroxine and retinol). .(MCQ)
      • It is characterized by severe peripheral nerve involvement caused by amyloid deposits.
    • Alzheimer disease

 

  • characterized by deposits A4 amyloid, or amyloid β-protein

 

      • gene that codes for the protein precursors of A4 amyloid has been localized to chromosome 21. (MCQ)
    • Familial Mediterranean fever
      • autosomal recessive disorder
      • characterized by episodic fever and polyserositis.
      • The distribution and type of amyloid are similar to that of secondary amyloidosis (AA amyloid). (MCQ)
    • Medullary carcinoma of the thyroid i
      • characterized by prominent amyloid deposits within the tumor
      • Amyloid is derived from calcitonin. (MCQ)
    • Diabetes mellitus
      • Seen in insulin-resistant adult-onset form (type 2) (MCQ)

 

  • characterized by deposits of amyloid in islet cells.
  • derived from either insulin or glucagon and is referred to as amylin or, alternatively, islet amyloid polypeptide.

 

    • It is postulated that amylin interferes with insulin sensing by beta cells.
  • Senile amyloidosis
    • involve the heart, brain, and other organs.
    • When senile amyloidosis occurs in the heart, the amyloid protein is derived from transthyretin. (MCQ)
  • Dialysis-associated amyloidosis
  • characterized by amyloid deposits in the joints of patients who have undergone hemodialysis for several years.
  • the amyloid is derived from β-microglobulin, a protein not readily filtered by the dialysis membrane(MCQ)