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 >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

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