Mechanisms of Neutropenia

Question 1

Neutropenia

Answer 1

Neutropenia occurs because migration of neutrophils to inflamed tissue exceeds the release of neutrphils from the bone marrow

Question 2

Severe Overwhelming, Inflammatory Neutropenia

Answer 2

• Mediated by:
  
  • cytokines from inflammatory site
• Increases migration of neutrophils to the tissues
• Increased release from storage and maturation pools
• Neutropenia with LEFT SHIFT

Question 3

Additional Mechanisms in Severe Gram Negative Infections

Answer 3

• Endotoxins stimulate sequestration of neutrophils in the marginating pool
• Mediated by:
  
  • cytokines from inflammatory site
  • ENDOTOXIN
• Shift from circulating to marginating pools
• Increase release from storage and maturation pools
• Will see as acute overwhelming inflammatory neutropenia

Question 4

Granulocytic Hypoplasia Neutropenia

Answer 4

• Occurs when marrow cells or cells in the microenvironment are damaged
• Marrow Disease:
  
  • causing decreased neutrophil production
• Persistent neutropenia
  
  • usually NO left shift
  • But may be present in infections, or marrow is starting to produce cells
  • Maturation is complete and orderly, but significantly decreased.

Question 5

Infective Production Neutropenia

Answer 5

• Occurs when neutrophils precursors are defective / damaged and die before release
• Disease causing defective/ineffective granulopoiesis
• Lack of orderly and complete maturation of neutrophil sequence
• Maturation arrest
  
  • commonly seen when viewing marrow samples

Question 6

Peripheral Destruction Neutropenia

Answer 6

• Immune mediated disease or hemophagocytic syndrome
• Increase form storage and maturation pools
• Hemophagocytic
  
  • infections
  • Neoplasia
• Destruction of neutrophils in blood.

Question 7

Species Differences

Answer 7