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