Lecture 4: Thrombocytopenia in Pediatric Patients

Question 1

At which platelet counts is spontaneous bleeding, clinically significant bleeding, and life threatening hemorrhage possible?

Answer 1

• Spontaneous = <50 x 10³/uL
• Clinically significant = <20 x 10³/uL***
• Life threatening = <10 x 10³/uL

Question 2

What are the 4 most common conditions associated with fetal/neonatal thrombocytopenia?

Answer 2

• Alloimmune thrombocytopenia
• Congenital infection (i.e., CMV, toxoplasma, rubella, HIV)
• Aneuploidy (i.e., triomy 18, 13, or 21 or triploidy)
• Autoimmune conditions (i.e., ITP, SLE)

Question 3

Kasabach-Merrit syndrome can be associated with early-onset neonatal (<72 hrs) thrombocytopenia and what other finding?

Answer 3

Large hemangiomas

Question 4

Late onset neonatal (>72 hr) thrombocytopenia is almost always due to what?

Answer 4

Late-onset sepsis

Question 5

Which disorder in children causing thrombocytopenia is a primary platelet consumption syndrome?

Answer 5

Idiopathic thrombocytopenia purpura

Question 6

Which 2 disorders causing thrombocytopenia in children are due to combined platelet and fbrinogen consumption syndromes?

Answer 6

• DIC
• Kasabach-Merritt syndrome

Question 7

Ecchymosis/bruising may be seen with platelet disorders in childre, you should worry if what 3 things are seen?

Answer 7

• Multiple
• Atypical distribution
• Bruising inconsistent with activity or force of injury

Question 8

A young male presenting with eczema, recurrent infections, and small platelets should make you think what?

Answer 8

Wiscott-Aldrich Syndrome

Question 9

How does acute idiopathic thrombocytopenic purpura (ITP) most commonly manifest in a child and what is the platelet level/morphology?

Answer 9

• Sudden onset of petechiae and bruising in otherwise well child; most often following a viral infection
• Platelet count usually <20x10³/uL —> platelets presents are usually large

Question 10

Which 3 treatments are most commonly used for acute ITP (usually only when severe or life-threatening hemorrhage)?

Answer 10

• IVIG
• Prednisone (or other corticosteroid)
• Anti-D immunoglobulin (only in Rh (-) children)

Question 11

After 12 months of ongoing ITP (chronic) in a child what other disorders should you evaluate for?

Answer 11

• Autoimmune diseases like SLE, chronic infections like HIV
• Non-immune causes like platelet type vWF, x-linked thrombocytopenia
• H. pylori infection***

Question 12

Hemolytic-uremic syndrome (HUS) is due to what?

Answer 12

Vascular injury (especially kidneys and colonic mucosa) from toxins from E.coli O157:H7 causing consumption of platelets

Question 13

What is the only cell line involved in ITP?

Answer 13

Platelets