What is the probable cause for thrombotic thrombocytopenic ...

[dakota nelson]

What is the probable cause for thrombotic thrombocytopenic purpura?
 
  a. Deficiency of a metalloprotease needed to enzymatically degrade unusually large von Willebrand factor (VWF) multimers
  b. Abnormal synthesis of unusually large VWF multimers by endothelial cells
  c. Abnormal synthesis of unusually large VWF multimers by megakaryocytes
  d. Abnormal complexing of normal VWF multimers to create unusually large VWF multimers

Question 2

What is the most common infectious cause of congenital neonatal megakaryocytic hypoplasia?
 
  a. Epstein-Barr virus
  b. Human immunodeficiency virus (HIV)
  c. Cytomegalovirus
  d. Rubella

[Loise Hard]

Answer to Question 1

ANS: A
Patients with the more common form of thrombotic thrombocytopenic purpura are deficient in a metalloprotease (ADAMTS 13) needed to cleave unusually large VWF into the smaller VWF multimers normally found in plasma. Both endothelial cells and megakaryocytes normally make these unusually large VWF multimers.

Answer to Question 2

ANS: C
Cytomegalovirus is the most common infectious agent causing congenital neonatal megakaryocytic hypoplasia. Cytomegalovirus appears to inhibit megakaryocytes and their precursors, resulting in impaired platelet production.

[dakota nelson]

TYSM

[dreamfighter72]

Excellent