November 23, 2010
Idiopathic Throbocytopenic Purpura
Idiopathic Thrombocytopenic Purpura
•Most common cause of isolated thrombocytopenia in otherwise healthy children
•Antiplatelet antibody▫Binds to platelet surface▫Destruction by phagocytosis (spleen, liver)
•50% follow viral illness•Following live vaccines (MMR)
Clinical Presentation
•History/Physical▫Sudden onset petechiae/bruising▫Mucosal hemorrhage 30%▫Severe bleeding in only 3%
•Labs▫Isolated thrombocytopenia
<20K (frequently <5K)▫Normal Hgb, MCV, WBC, PT/PTT▫Smear unremarkable
paucity of platelets (large platelets)
Acute ITP•Resolves spontaneously within 6 months•Bleeding tendency lessens within 1-2wks
Treatment
•Avoidance of NSAIDS•Limit activities
▫No contact sports•Reassurance of parents
Reassurance
•Life-threatening hemorrhage very rare▫Intracranial hemorrhage 0.5 to 0.1%
•Young platelets▫Large▫Metabolically active▫“Sticky”▫Underestimated by cell counter
Treatment
•Prednisone•IVIG•Rho(D) Immune Globulin•Avoid platelet transfusion
▫Rapidly destroyed▫Consider with life-threatening bleed
Treatment: Steroids
•Prednisone▫1-2 mg/kg/day▫Decreases as prednisone tapered (2-3wks)
Treatment: IVIG
•Costly•More effective than steroids•80-90% plts >20k within 3 days•Not shown to prevent serious bleeding•Side effects
Treatment: Rho(D) Immune globulin
•May be used if:▫Hgb >10▫Rh +
•Efficacy similar to that of IVIG•Hemolysis possible
Chronic ITP
Chronic ITP
•>6 months duration•Generally benign
▫Not requiring aggressive therapy•Platelets 30-80k•Some bruising and petechiae
Chronic ITP
•Treatment with steroids, IVIG, Rho(D)IG▫Transient increased platelets▫Not curative
•Useful in emergency or at surgery
Chronic ITP
•Most improve over time•Allow school and childhood activities
▫NO contact sports•Splenectomy in refractory cases
▫60-80% cure rate
Congenital Disorders
Wiskott-Aldrich Syndrome
•X-Linked•Recurrent infections
▫Otitis, Pneumonia•Thrombocytopenia
▫LOW MPV (mean plt volume)•Risk for malignancies•Treatment: B.M. Transplant
Thrombocytopenia Absent Radius
•WBC usually high•Normal Hgb•Symptomatic by 4 m/o
Think about it…
•Child with bleeding•Normal:
▫Plt count▫Coags
•Glanzmann Thrombasthenia•Disorder of platelet Function
•NSAIDS overdose•Abnormal function