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Toronto Notes 2019 Hematology Pediatrics P43 Vitamin K Deficiency
Etiology
• hemorrhagicdiseaseofthenewbornduetorelativedeficienciesofvitaminK-dependentcoagulation factors
■ generalized bleeding; GI/intracranial hemorrhage
• IMinjectionatbirth,canalsobegivenorally(3doses:atbirth,2-4wk,6-8wk)butinfantsathigherrisk
of HDNB
• reasonforadministrationatbirth:
■ human milk contains small amounts of vitamin K, and infants require ingestion of large volumes of human milk to promote GI bacterial colonization
■ until few days after birth, susceptible to vitamin K deficiency
Anemia of Chronic Disease
• seeHematology,H6
Sickle Cell Disease
• seeHematology,H20 Thalassemia
• seeHematology,H19
Hereditary Spherocytosis
• seeHematology,H22
Glucose-6-Phosphate Dehydrogenase
Deficiency
• seeHematology,H23
Bleeding Disorders
• seeHematology,H25
Table 20. Evaluation of Abnormal Bruising/Bleeding
G6PD deficiency protects against parasitism of RBCs (i.e. malaria)
Extensive bruising in the absence of lab abnormalities: consider child maltreatment
PFA PT
Hemophilia A N N
PTT
VIII:C vWF
Platelets
Fibrinogen
Hemophilia B
von Willebrand Disease
DIC
Vitamin K Deficiency
Thrombocytopenia h N
N or h i h i h N N N
N or i N N N i i NN N Ni N
N N
h i N N N hNNN N
h N N or h h N h
DIC = disseminated intravascular coagulation; PFA = platelet function assay; VIII:C = Factor VIII coagulant activity; vWF = von Willebrand Factor
Immune Thrombocytopenic Purpura
Epidemiology
• mostcommoncauseofthrombocytopeniainchildhood • peakage:2-6yr,M=F
• incidence5:100,000childrenperyear
Etiology
• causedbyautoantibodiesthatbindtoplateletmembranes→Fc-receptormediatedsplenicuptake→ destruction of platelets