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ITP Presentation

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Immune (idiopathic)
Thrombocytopenic
Purpura
Epidemiology

The most common cause of acute onset of thrombocytopenia (usually <20K) in
an otherwise healthy child

A recent history of viral illness is described in 50-60% of cases of childhood ITP


Typically 1-4 weeks after exposure

Peak age 2-6y
Slightly increased risk of developing ITP within 6 weeks of MMR vaccine (2.6
per 100,000 doses)
Pathogenisis

Autoantibody directed against
platelet surface (glycoprotein
complex IIb/IIIa) After binding,
circulating antibody-coated
platelets are destroyed by splenic
macrophages

In chronic ITP, T cell mediated
cytotoxicity may cause platelet
destruction
Diagnosis


ITP is a clinical diagnosis and diagnosis of exclusion

PLT <100K

Otherwise normal CBC including WBC, Hgb, reticulocyte counts

No abnormalities on peripheral smear (no evidence of hemolysis or blasts)

Negative DAT

No findings on history or PE to suggest alternative dx (systemic symptoms, palpable lymph nodes, splenomegaly)
Hemoglobin, WBC, and differential should all be normal

Consider bone marrow aspiration if abnormal

A DAT (Coombs) should be performed if unexplained anemia to rule out Evans syndrome (autoimmune
hemolytic anemia w/ thrombocytopenia) before giving anti-D

Diagnosis:2 criteria
1.Isolated thrombocytopenia,with otherwise normal blood counts and peripheral smear.
2.No clinically apparent associated conditions that may cause thrombocytopenia
Exclude concurrent inf/autoimmune disorders/malignancy/drugs/genetic bleeding disorders/ marrow failure
Differential Diagnosis

Viral infection(IMN,Hepatitis,HIV- 1)

Drug exposure(Heparin, Quinidine, Sulfonamide)

Autoimmune Disorders(SLE)

Leukemia (ALL)

Acquired marrow failure syndrome (aplastic anemia)

Inherited thrombocytopenic disorders(thrombocytopenia-absent radius
syndrome, Wiskott-Aldrich syndrome,mutation of MYH 9 gene)
Clinical Presentation

Sudden appearance of bruising and/or bleeding in an otherwise healthy child

Mild if bruising and petechiae

Moderate if presence of mucosal lesions

Severe if significant bleeding episodes (i.e. menorrhagia, epistaxis, melena

In one large cohort study, mucosal bleeding was more common with PLT count <10K compared with >15K
(51% vs 19%)

Approximately 80% will have PLT <20K at presentation, and 45% will have PLT <10K
History:

No systemic symptoms

Presence of systemic symptoms like fever ,anorexia, joint pain, bone pain or weight loss usually points to
other diagnosis

Drug induced (heparin, quinidine, sulfonamides) thrombocytopenia is uncommon in kids

Disease course: 70% of children have the acute form of ITP, which is defined by recovery (platelet count
>150,000/ micro L) in 6 months of presentation with or without treatment. Treatment do not affect the
long term outcome,but minimize the risk of significant bleeding
Treatment

Ideal management still unclear: observation alone vs observation with
pharmacologic intervention

Initial approach includes no therapy other than education and counseling with
minimal, mild, or moderate symptoms

Restrict contact sports/physical activity

Avoid medications with antiplatelet or anticoagulant activities

Platelet transfusion is usually contraindicated unless there is life-threatening
bleeding due to binding of antiplatelet antibodies to transfused platelets

Presence of severe life threatening bleeding, risk of significant bleeding
(planned procedures/count <10K, and cutaneous bleeding), comorbid
conditions (hemophilia) requires intervention
IV IG:
Mechanism of action is multi-factorial,inhibition of antibody adsorption to
platelets,prevention of RES uptake of auto ab coated platelets, interaction of
auto abs with idiotype abs in IV IG.
Works better than steroids but higher cost
Dose:
400mg /kg/day x 5 days
OR
Single dose of 1g/kg


IVIG induces rapid rise in platelet count in 95% of patients within 48hrs

IVIG appears to induce a response by downregulating Fc-mediated phagocytosis of
antibody-coated platelets

IV IG – 500 mg /kg/day x 2 days ,and may be repeated if the symptoms recur

Corticosteroids:

DO NOT GIVE STEROIDS UNTILL OTHER DIAGNOSIS ARE EXCLUDED,AS THE
STEROIDS CAN MASK EARLY LEUKEMIA.
Reduce Ab production,RES phagocytosis of antibody coated platelets,improve
vascular integrity, improve platelet production
Prednisone 1-2 mg/kg/day(max 60 /day) in 3 divided doses x 2-4 wks, followed
by a taper of 4mg / kg/day ,divided into 3 doses for 4 days
OR
Methylprednisolone( 30-50 mg /kg/day) for 3-7 days
Some cases may need repeat courses
CORTICOSTEROIDS-short course/pulse course

Anti-D for Rh positive patients

Anti-Rho(D) immune globulin: has been shown to be effective

Platelet transfusion: used in case of life threatening bleeding(ICH)

The therapy is targeted to increase count to >20,000.In risk of life
threatening bleeding , IV IG could be repeated or combined with steroids

Monitoring: the patients getting pharmacologic intervention the usual hospital
stay is 2 days.In the ambulatory setting ,platelet count monitored 1-2 times
/wk ,interval can increase as the platelet increase .monitoring is necessary
until the count return to >150,000/microL(50% in 1 mont,70% in 3 months)
Chronic ITP

Approximately 10-20% of children who initially present with ITP will become
chronic defined as PLT <100K for >12 months

Risk factors include older age, higher presenting platelet count at diagnosis,
insidious onset of symptoms, and lack of preceding infection or vaccination

Chronic ITP: persistent thrombocytopenia(<150,000/microL) for > 6 months
20-30% will have chronic ITP
1/3 rd of the cases will have spontaneous remission in months to years
In chronic ITP the platelet count ranges between 20,000-75,000/microL.usually
do not require any treatment
Management: decrease the risk for bleeding.
Role of Splenectomy

Older child >4yoa with severe ITP lasting >1 year (chronic ITP)

Symptoms not easily controlled with therapy

Life-threatening hemorrhage complicating acute ITP

Platelet count cannot be corrected rapidly with transfusion of platelets and
administration of IVIG and corticosteroids

SPLENECTOMY- may be needed in patients needing repeated /continuous
pharmacologic intervention even 12 months after diagnosis
Prognosis

Father asked question is it going to happen again

Severe bleeding is rare (<3% of cases)

ICH occurs in <1% of patients

70-80% will have spontaneous resolution in 6 months

Approximately 20% who present with acute ITP will go on to have chronic ITP

This increases to 50% in adolescents
Take Away points
References

UpToDate

D'Orazio JA, Neely J, Farhoudi N. ITP in children: pathophysiology and current
treatment approaches. J Pediatr Hematol Oncol 2013; 35:1.

Provan D, Stasi R, Newland AC, et al. International consensus report on the
investigation and management of primary immune thrombocytopenia. Blood
2010; 115:168.
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