Manifestations of ITP in Children


Newly diagnosed ITP

Resolution within 3 months of diagnosis

Persistent ITP

Resolution 3–12 months from diagnosis; includes patients not reaching spontaneous remission or not maintaining complete response off therapy

Chronic ITP

Lasting more than 12 months





6 Onset of ITP Children


ITP can develop at all ages in children. In newborns, thrombocytopenia developing from antiplatelet antibodies transferred through the placenta from a mother with ITP to the fetus is called passive ITP [22]. ITP in children mainly occurs after viral or bacterial infection or vaccination [23, 24].


7 Clinical and Laboratory Characteristics


Bleeding symptoms are mainly bruising and mucocutaneous bleedings such as petechiae (diameter of 0.5–3 mm, no blanching under pressure, not palpable) or ecchymosis (flat, rounded, or irregular red, blue, purplish, or yellow-green patch larger than petechiae), oral or nasal bleeding, hematuria, or hypermenorrhea. Rarely, organ bleeding such as gastrointestinal or intracranial bleeding occurs [25]. Patients are often noticed incidentally during laboratory examinations performed for unrelated diseases. ITP in children is more frequent in males, whereas adult ITP more involves females. Severe bleeding is rare and is found in children with a platelet count less than 20 × 109/L [4, 26, 27]. Predictors of bleeding due to ITP in children include female sex, older age at presentation (age ≥11 years), absence of preceding infection or vaccination, insidious onset, higher platelet count at presentation, presence of antinuclear antibodies, and treatment with a combination of methylprednisolone and intravenous immunoglobulin. Furthermore, children with mucosal bleeding at diagnosis or treatment with intravenous immunoglobulin alone develop chronic ITP less often [7].


8 Bleeding Assessment Tools (BATs) for ITP in Children


The bleeding risk and severity of ITP have usually been evaluated based on peripheral platelet counts and bleeding symptoms. However, objective evaluation of the degree or severity of bleeding symptoms is not easy. Various BATs have been proposed for ITP in children and adults [25, 2832]. More recently, a new standard in bleeding assessment for ITP in children and adults (ITP-BAT bleeding scale, version 1.0) has been reported from the IWG.

The ITP-BAT bleeding scale is made up of three major bleeding domains of the skin (S), visible mucosae (M), and organs (O), with a gradation of severity (SMOG index). The gradation of severity for each domain is further classified on the site of bleeding with gradings ranging from 0 to 3 or 4 according to the spread of the hemorrhagic area, need for medical intervention and red blood cell transfusion, and reductions in levels of blood hemoglobin. For example, a SMOG index of S2 M2 O3 could represent findings of subcutaneous hematoma (S2), epistaxis (M2), and menorrhagia (O3). Considering the lifelong potential functional impairment caused by intracranial bleeding, the IWG recommends that all cases of intracranial bleeding be reported, irrespective of grade, such as S grade 2 M grade 2 O grade 3 (intracranial grade 2; post trauma, requiring hospitalization). However, the value of summing up the worst grades for all manifestations in each domain is currently uncertain, and interpretation remains ambiguous [25].


9 Diagnosis of ITP in Children


Information about the family and medical history before onset are important. The characteristics of bleeding symptoms and physical and laboratory examinations are crucial for differential diagnosis. The Japanese Society of Pediatric Hematology/Oncology proposed diagnostic criteria for pediatric ITP (Table 2) [33]. However, no gold standards exist for ITP diagnosis, and exclusion of other thrombocytopenic disorders remains central to the diagnosis. Bone marrow examination is usually unnecessary in children and adolescents with typical features of ITP, but when abnormal physical symptoms (such as abnormal rash, recurrent fever, or joint pain), lymphadenopathy, splenomegaly, abnormal cell counts, abnormal morphology of red or white blood cells, and poor response to medical treatments such as immunoglobulin and corticosteroids are present, bone marrow evaluation may be needed to rule out other disorders. In recent years, measurement of plasma levels of TPO, TPO receptor protein, and immature platelets (reticulo-platelets), which may indicate platelet production in the bone marrow, has been developed as complementary inspection methods [8].


Table 2
Diagnostic criteria for ITP children according to the Committee on Platelets of the Society of Japanese Pediatric Hematology/Oncology































1. Bleeding symptoms present
 
Bleeding symptoms as mainly purpura (petechia or ecchymosis) and also oral bleeding, epistaxis, melena, hematuria, hypermenorrhagia
 
Joint bleeding does not usually occur. Although patient would be unaware of a bleeding symptom, patient is admitted to clinic after identification of thrombocytopenia

2. Laboratory findings
 
a. Peripheral blood examinations

 • Decreased platelets: <100 × 109/L. It should be noted that attention to false thrombocytopenia is required when performing automatic blood cell counting

 • Numbers and morphological features of both red and white blood cells are normal. However, as for bleeding tendency or iron-deficiency anemia, a mild increase or decrease of white blood cells may also be observed.
 
b. Bone marrow

 • Numbers of megakaryocytes are normal or increased:

   Many megakaryocytes lack platelet production

 • Numbers or morphological features of both red blood cells and granulocyte lineages are normal:

   Granulocyte/erythroid (G/E) ratio overall; production of both lineages is present

   Bone marrow examination is not routinely conducted for diagnosis of ITP

   Bone marrow examination is considered at the presence of abnormal numbers and morphological feature of red and/or white blood cells, at disputable diagnosis of ITP, with the considerable use of corticosteroids or absence of desirable response to administration of large amounts of gamma globulin

3. Exclusion of various diseases that can cause thrombocytopeniaa

4. ITP diagnosis can be made if the characteristic features of points 1–3 are presentb

5. Criteria of ITP phase
 
a. Acute phase: Recovery from thrombocytopenia within 6 months from estimated onset or diagnosis

b. Chronic phase: Thrombocytopenia prolonged for 6 months or more from estimated onset or diagnosis preceding virus infection often indicates acute-phase ITP


aMajor diseases resulting in thrombocytopenia in childhood

bMeasurement of specific antiplatelet antibody is useful for ITP diagnosis, but no laboratory system is available in Japan

Primary decrease of platelet production: Drug- or radiation-associated thrombocytopenia, aplastic anemia, leukemia, myelodysmorphic syndrome, bone metastasis of cancer, etc.

Primary increase in platelet destruction: Systemic lupus erythematosus, and related diseases, antiphospholipid antibody syndrome, disseminated intravascular syndrome, hemolytic uremic syndrome (HUS), thrombotic thrombocytic purpura (TTP), hemophagocytic syndrome, HIV infection, Kasabach-Merritte syndrome, etc.

Both decreased platelet production and platelet destruction, such as severe infectious disease, etc.

Congenital thrombopenia: Bernard-Soulier syndrome, Wiskott-Aldrich syndrome, X-linked thrombocytopenia, May-Hegglin syndrome, Epstein syndrome, gray platelet syndrome, von Willebrand disease (type “B” and platelet type), amegakaryocytic thrombocytopenia, etc.


10 Differential Diagnoses


A diagnosis of ITP is reached by excluding underlying disorders with thrombocytopenia caused by platelet destruction and/or production and congenital thrombocytopenia. Diagnosis of congenital thrombocytopenia is not easy and is usually achieved based on platelet size and morphology in peripheral blood specimens, clinical manifestations of hemorrhagic and nonhemorrhagic symptoms, and results of platelet-function tests such as platelet aggregation tests using three different inducers adenine diphosphate (ADP), collagen and ristocetin, platelet-membrane glycoprotein analysis, flow-cytometric analysis with specific-labeled antiplatelet antibodies, electron microscopic analysis, or genetic analysis. A recent distinction algorithm using platelet size for congenital thrombocytopenia is shown in Table 3 [34, 35].


Table 3
Classification of congenital thrombocytopenia by platelet size



































































































Platelet size

Mode of inheritance

Gene

Remarks

Small (MPV: <5 fLa)

 Wiskott-Aldrich syndromea

X, AR

WAS, WIPF1

Immunodeficiency, eczema, thrombocytopenia

 X-linked thrombocytopenia

X

WAS

Thrombocytopenia (mild eczema, susceptibility to infection)

Normal (MPV: 7.2–11.7 fL, 3–4 μm in diameterb)

 Congenital amegakaryocytic thrombocytopenia

XR

MPL

Reduced megakaryocytes, transition to bone marrow failure

 Congenital thrombocytopenia with radioulnar synostosis

XD

HOXA11

Radioulnar fusion, transition to bone marrow failure

 Thrombocytopenia with absent radii syndrome

XR

RBM8A

Radial defect, normalization of platelet count with age

 Familial platelet disorder with propensity to myeloid malignancy

XD

RUNX1 (AML1)

Transition to AML/MDS

 Autosomal-dominant thrombocytopenia, thrombocytopenia 2

XD

ANKRD26

Reduction of GP1a and α granules, transition to acute leukemia

Cytochrome C mutation

XD

CYCS (G41S mutation)

Apoptosis of megakaryocytes

Large (more than twice normal platelets, ≥8 μm in diameter)

 MYH9 disorders

AD

MYH-9
 

  May-Hegglin syndrome
   
Clear white blood cell inclusions

  Sebastian syndrome
   
Somewhat ambiguous white blood cell inclusion bodies

  Fechtner syndrome
   
Combined with glomerulonephritis and deafnessc

  Epstein syndrome
   
Combined with glomerulonephritis and deafness, leukocyte inclusion bodies difficult to recognize

 Bernard-Soulier syndrome

AR

GP1BA, GP1BB, GP9

Lack of ristocetin-induced platelet aggregation

 DiGeorge/velocardiofacial syndrome

AD

22q 11.2 del (GP1BB)

Contiguous gene syndrome

 α-Actinin abnormality

AD

ACTN1

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Sep 18, 2017 | Posted by in HEMATOLOGY | Comments Off on Manifestations of ITP in Children

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