10.17.18 Thrombocytopenia Flashcards
Too few platelets
Thrombocytopenia
Too many platelets
Thrombocytosis
platelet clumping where platelet count is artificially low
Pseydothrombocytopenia
What are the categories of causes for thrombocytopenia?
- Underproduction
- Peripheral Destruction
- Splenic Sequestration
What are causes for underproduction?
- Marrow failure
- Marrow infiltration
- Marrow toxins
A process, characterized by abnormal activation of coagulation, generation of thrombin, consumption of clotting factors, destruction of platelets, and activation of fibrinolysis
Disseminated Intravascular Coagulation (DIC)
How do you diagnose DIC?
- Elevated PT
- Low platelets
- Low fibrinogen
- Elevated D-Dimers
- Schistocytes
How do you treat DIC
Treat the underlying cause
- Sepsis
- Burns
- OB probs
- Leukemia
- Shock
- Venom
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
Thrombotic Thrombocytopenic Purpura (TTP)
How do you diagnose TTP?
- MAHA
- Schistocytes (NEED)
- Low platelets (NEED)
- Fever
- Neurologic Manifestations
- Renal Manifestations
How is TTP caused?
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
What drugs can induce TTP?
Quinine, Cyclosporine, Tacrolimus
There is an increased incidence of TTP with what?
- Pregnancy
2. HIV/AIDS
How do you treat TTP?
PLEX with corticosteroids
Secondary: Splenectomy, Vincristine
Relapse: Rituximab
AVOID PLATELET TRANSFUSION
Usually classified with TTP but has fewer neurologic sequelae and more renal manifestations
Hemolytic Uremic Syndrome (HUS)
What usually causes HUS?
E.Coli or Shigella –> Shiga Toxin
This is HUS without the diarrheal prodrome
Atypical HUS
How is Atypical HUS started?
- Disorder of complement regulation
2. Pregnancy/infection trigger
What are diagnostic features of atypical HUS?
- MAHA
- Low platelets
- Renal failure
- Evidence of complement activation
How do you treat atypical HUS?
- PLEX
2. Eculizumab
What drugs cause thrombocytopenia?
- Beta-lactam antibiotics
- Trimethoprim-sulfamethoxazole and other sulfa drugs
- Quinine/Quinidine
- Heparin (if platelets fall on this stop immediately)
This disorder has no diagnostic test but is suspected in patients with isolated thrombocytopenia
Immune/Idiopathic Thrombocytopenic Purpura (ITP)
How do you treat ITP?
- Corticosteroids
- If platelet count is less that 10K use IVIg
Second line: Rituximab, Splenectomy
When do you do platelet transfusion with
ITP TTP DIC Splenic Sequestration Hypoproduction?
ITP- only severe bleeding TTP- DON'T DIC- give to treat bleeding Splenic sequestrations- reserve for severe bleeding Hypoproduction- less than 10K transfuse
What are myeloproliferative syndromes?
- Essential Thrombocythemia
- Polycythemia Vera
- CML
- Myelofibrosis
What causes secondary thrombocytosis?
- Inflammation
- Infection
- Bleeding
- Iron-deficiency
- Post-splenectomy
