Pediatric Thrombocytopenia Van Garsse

Question 1

platelet counts- normal, primary hemostasis impaired, spontaneous bleeding, clinically significant bleeding, life threatening hemorrhage

Answer 1

• normal- 150-450,000
• primary hemostasis impaired- 75
• spontaneous bleeding- 50
• clinically significant bleeding- 20
• life threatening hemorrhage- 10

Question 2

causes of thrombocytopenia

Answer 2

• dec platelet prod
• dec platelet survival
• sequestration
• dilution

Question 3

Dec platelet production- marrow shows? causes?

Answer 3

• less megakaryocytes
• bone marrow failure of infiltration
• infection
• cyanotic HD
• nutritional def
• genetic defects

Question 4

bone marrow failure/infiltration- if assoc with anemia and leukopenia- caused by?

Answer 4

• leukemia or other malignancy
• acquired aplastic anemia
• myelodysplasia
• inherited bone marrow failure syndromes- Fanconi pancytopenia syndrome, Dyskeratosis congenita

Question 5

Infection

Answer 5

• caused by bone marrow suppression
• most commonly viral
• transient- recovery in a few wks

Question 6

cyanotic HD

Answer 6

-probably due to dec prod of megakaryocytes

Question 7

nutritional deficiencies

Answer 7

• folate, B12- impairs bone marrow prod- pancytopenia

- iron- impairs thrombopoiesis

Question 8

genetic causes

Answer 8

• defects of megakaryocyte lineage that result in impaired thrombopoiesis
• consider in pts with a long hx of asx abnormal plt counts, or other family members with low plts

Question 9

Increased platelet destruction- causes

Answer 9

• Immune- ITP, infection, heparin

- nonimmune (mechanical)- DIC, HUS, TTP, infection

Question 10

Acute ITP (immune thrombocytopenic purpura)

Answer 10

• isolated thrombocytopenia (in absence of any underlying cause!!!)
• most common cause of isolated thrombocytopenia in OTHERWISE WELL CHILDREN!!

Question 11

Acute ITP- incidence, presentation

Answer 11

• 2-10 yo
• sudden onset of bruising/petechiae or mucocutaneous bleeding
• otherwise healthy child!!!
• 50% after viral illness!
• NO systemic sx’s
• no LA or HSM

Question 12

Acute ITP- criteria

Answer 12

• Isolated thrombocytopenia with otherwise normal blood counts and PBS!!!
• no clinically apparent assoc conditions that may cause thrombocytopenia

Question 13

ITP- classification

Answer 13

• acute- <6 months
• chronic >6 months
• usually short lived, 75% make full recoveries within 6 months of presentation

Question 14

ITP- lab

Answer 14

• CBC- plt count

- peripheral smear- plt morphology, schistocytes, + direct coombs, fibrin degradation products

Question 15

ITP- tx?

Answer 15

-no tx alters the natural hx

Question 16

ITP- red flags

Answer 16

• constitutional sx’s
• Hx of dz with low plts
• dietary hx- Fe, B12, folate def
• exposure to meds
• PE findings other than signs of bleeding

Question 17

other causes of acute thrombocytopenia

Answer 17

• TTP

- HUS- more common in children (E coli)

Question 18

chronic ITP- tx

Answer 18

only curative tx is splenectomy!

-60-80% long term response rate

Question 19

HUS

Answer 19

• E coli

- microangiopathic hemolytic anemia, thrombocytopenia, acute renal failure