Pathophysiology of Neutropenia and Thrombocytopenia

Question 1

Neutropenia

Answer 1

Significant reduction in the number of neutrophils

Can result in serious infection called agranulocytosis

Question 2

Margination and Demargination

Answer 2

Netrophils are constantly exchanging with neutrophils that are stuck in the wall (marginated cells)

Question 3

Causes of demargination

Answer 3

Infection, exercise, epinephrine, corticosteroids, SCA

Question 4

Causes of margination

Answer 4

Malaria, virus, hemodialysis

Question 5

Reduction in the production of neutrophils

Answer 5

Suppression of myeloid stem cells (aplastic bone marrow or hypoplastic bone marrow)
Suppression of granulocytic precursors which occur after exposure
Congenital disease (Kostmann syndrome)

Question 6

Accelerate removal of neutrophils

Answer 6

Immunologic disorder or exposure to drugs
Splenic sequestration
Infection or cancer

Question 7

Thrombocytopenia

Answer 7

Plt count below 100,000 plts

Question 8

Classification of thrombocytopenia

Answer 8

Decreased production of plts
Decreased plt survival
Sequestration
Dilution

Question 9

Decreased production of platelet

Answer 9

Drug induced or infections
Deficiency
Aplastic
Bone Marrow Replacement
Ineffective hematopoiesis

Question 10

Decreased plt survival

Answer 10

Chronic or acute ITP
Alloimmune
Drug or infxn
Coagulation or microangiopathies/hemangiomas

Question 11

Sequestration

Answer 11

Normally 30-35%

Hypersplenism 80-85%

Question 12

Dilution

Answer 12

Transfussion dilution

Question 13

Chronic ITP

Answer 13

Autoantibodies to platelets
Autoantibodies against glycoproteins IIb-IIIa or Ib-IX
Anti-plts act as opsonins that are recognized by IGG Fc receptors expressed on phagocytes – increased plt destruction
Large plts

Question 14

Clinically Chronic ITP…

Answer 14

WOMEN
Petechiae or ecchymoses
Low plt count
Megakaryocytes increased in bone marrow
Large plts

Question 15

Treatment of ITP

Answer 15

Glycocorticoids
Splenectomy
IVIG or anti-CD20

Question 16

Acute ITP

Answer 16

Autoantibodies to plts during childhood
Following a viral infection
Resolves spontaneously within 6 months

Question 17

Drug induced thrombocytopenia

Answer 17

Heparin induced –> platelet aggregation

Activates platelets and promotes thrombosis

Question 18

Thrombotic Microangiopathis

Answer 18

TTP and HUS caused bhy insults that lead to excessive activation of plts –> deposit as thrombi

Question 19

TTP

Answer 19

ADAMTS13: decreases vWF

Absence leads to accumulations and promotes plt activation and aggregation

Question 20

HUS

Answer 20

Associated with infectious gastroenteritis caused by E.coli

Can prevent excessive activation of the alternative complement pathway