10.17.18 Thrombocytopenia

Question 1

Too few platelets

Answer 1

Thrombocytopenia

Question 2

Too many platelets

Answer 2

Thrombocytosis

Question 3

platelet clumping where platelet count is artificially low

Answer 3

Pseydothrombocytopenia

Question 4

What are the categories of causes for thrombocytopenia?

Answer 4

1. Underproduction
2. Peripheral Destruction
3. Splenic Sequestration

Question 5

What are causes for underproduction?

Answer 5

1. Marrow failure
2. Marrow infiltration
3. Marrow toxins

Question 6

A process, characterized by abnormal activation of coagulation, generation of thrombin, consumption of clotting factors, destruction of platelets, and activation of fibrinolysis

Answer 6

Disseminated Intravascular Coagulation (DIC)

Question 7

How do you diagnose DIC?

Answer 7

1. Elevated PT
2. Low platelets
3. Low fibrinogen
4. Elevated D-Dimers
5. Schistocytes

Question 8

How do you treat DIC

Answer 8

Treat the underlying cause

• Sepsis
• Burns
• OB probs
• Leukemia
• Shock
• Venom

Question 9

A process, characterized by abnormal activation of platelets and endothelial cells, with vWF and fibrin deposition in the microvasculature, and peripheral destruction of platelets and RBC

Answer 9

Thrombotic Thrombocytopenic Purpura (TTP)

Question 10

How do you diagnose TTP?

Answer 10

1. MAHA
2. Schistocytes (NEED)
3. Low platelets (NEED)
4. Fever
5. Neurologic Manifestations
6. Renal Manifestations

Question 11

How is TTP caused?

Answer 11

Sporadic but there is an autoantibody against ADAMTS-13 which is a protease that cleaves vWF. W/o it there is an accumulation of large vWF and abnormal platelet activation

Question 12

What drugs can induce TTP?

Answer 12

Quinine, Cyclosporine, Tacrolimus

Question 13

There is an increased incidence of TTP with what?

Answer 13

1. Pregnancy

2. HIV/AIDS

Question 14

How do you treat TTP?

Answer 14

PLEX with corticosteroids
Secondary: Splenectomy, Vincristine
Relapse: Rituximab

AVOID PLATELET TRANSFUSION

Question 15

Usually classified with TTP but has fewer neurologic sequelae and more renal manifestations

Answer 15

Hemolytic Uremic Syndrome (HUS)

Question 16

What usually causes HUS?

Answer 16

E.Coli or Shigella –> Shiga Toxin

Question 17

This is HUS without the diarrheal prodrome

Answer 17

Atypical HUS

Question 18

How is Atypical HUS started?

Answer 18

1. Disorder of complement regulation

2. Pregnancy/infection trigger

Question 19

What are diagnostic features of atypical HUS?

Answer 19

1. MAHA
2. Low platelets
3. Renal failure
4. Evidence of complement activation

Question 20

How do you treat atypical HUS?

Answer 20

1. PLEX

2. Eculizumab

Question 21

What drugs cause thrombocytopenia?

Answer 21

1. Beta-lactam antibiotics
2. Trimethoprim-sulfamethoxazole and other sulfa drugs
3. Quinine/Quinidine
4. Heparin (if platelets fall on this stop immediately)

Question 22

This disorder has no diagnostic test but is suspected in patients with isolated thrombocytopenia

Answer 22

Immune/Idiopathic Thrombocytopenic Purpura (ITP)

Question 23

How do you treat ITP?

Answer 23

1. Corticosteroids
2. If platelet count is less that 10K use IVIg

Second line: Rituximab, Splenectomy

Question 24

When do you do platelet transfusion with

ITP
TTP
DIC
Splenic Sequestration
Hypoproduction?

Answer 24

ITP- only severe bleeding
TTP- DON'T
DIC- give to treat bleeding
Splenic sequestrations- reserve for severe bleeding
Hypoproduction- less than 10K transfuse

Question 25

What are myeloproliferative syndromes?

Answer 25

1. Essential Thrombocythemia
2. Polycythemia Vera
3. CML
4. Myelofibrosis

Question 26

What causes secondary thrombocytosis?

Answer 26

1. Inflammation
2. Infection
3. Bleeding
4. Iron-deficiency
5. Post-splenectomy