Idiopathic thrombocytopenic purpura

IDIOPATHIC THROMBOCYTOPENIC PURPURA
It’s a bleeding disorder
IT IS A DISEASE CHARCTERISED BY SEVER REDUCTION OF PLATELET NUMBERS, CAUSED BY IMMUNE DESTRUCTION OF PLATELETS.
THE MECHANISM OF I.T.P. APPEARS TO BE IMMUNE COMPLEXES CONTAINING ANTIBODIES, WHICH REACT WITH PLATELETS AND LEADS TO THEIR IMMUNOLOGICAL DESTRUCTION.

IMMUNE THROMBOCYTIC PURPURA ( ITP )
( IDIOPATHIC THROMBOCYTOPENIC PURPURA ) Autoimmune antibodies against platelets from respone to previous viral infection (ACUTE ITP) or
from underlying dysregulation ( CHRONIC ITP )
Causes
Immunoglobulin G (IgG) autoantibodies on the platelet surface.
PLATELET DESTRUCTION
(THROMBOCYTOPENIA)

CLINICAL MANIFESTATIONS
Clinical signs and symptoms of ITP are reflective of thrombocytopenia and,
( bleeding manifestation due to decreased platelet count)

CHARACTERISTIC CLINICAL FEATURES
Common signs, symptoms, and precipitating factors include the following:
Petechiae – small 2mm Red or Purple spot on skin caused by bleeing from broken cappillaris and blood vessels. Often located on extremities or on mucous membrane.
Ecchymosis – bleeding underneath the skin typically caused by bruising >1-2cm
Purpura – red or purple spot on skin that does’t blench on applying pressure >3mm
Menorrhagia – Menstrual period with abnormally prolonged heavy bleeding
Epistaxis
Gingival bleeding
Recent live virus immunization (childhood ITP)
Recent viral illness (childhood ITP)
Bruising tendency – red blood clotting disorder.

PATHOGENESIS OF I.T.P.
Increased platelet destruction caused by anti platelet antibodies ? antibodies directed against platelet membrane antigen.
Lack of compensatory response by megakaryocytes due to suppressive effect of anti platelet antibodies
So, a combination of increased platlet destruction + ineffective megakaryopoiesis.
Pathogenesis was proved by harrington when he infused hemself with plasma from a women with ITP (Harrington hollisworth Experiment)
ITP is primarily a disease of increased peripheral platelet destruction, with most patients having antibodies to specific platelet membrane glycoproteins. Relative marrow failure may contribute to this condition, since studies show that most patients have either normal or diminished platelet production.

CLINICAL FEATURES THAT ARE CHARACTERISTRISTICALLY UNUSUAL AND SUGGEST THE POSSIBILITY OF OTHER DIAGNOSIS :-
Clinical history & Physical examination of Patient
CBC & Peripheral blood smear
Testing for autoimmune disorder & exclusion of HIV antiplatelet.
Frequent bleeding and haemorrhages from larger veins and arteries and bleeding into joints (SUGGEST COAGULATION DISORDER)
Splenomegaly and lymphadenopathy are the unusual/rare and their presence should lead one to consider other diagnosis.
Hepatomegaly, splenomegaly and lymphadenopathy are notably absent in ITP and their presence should initiate an investigation for other possible underlying illnesses associated with thrombocytopenia.

DIAGNOSTIC CONSIDERATIONS
OTHER PROBLEMS TO BE CONSIDERED IN THE DIFFERENTIAL DIAGNOSIS INCLUDE THE FOLLOWING:
PSEUDOTHROMBOCYTOPENIA (PLATELET CLUMPING IN THE PRESENCE OF ETHYLENEDIAMINETETRAACETIC ACID [EDTA])
LIVER DISEASE
MYELODYSPLASIA
LYMPHOPROLIFERATIVE, AUTOIMMUNE, OR INFECTIOUS DISEASES
PREGNANCY-ASSOCIATED THROMBOCYTOPENIA
DRUG-INDUCED IMMUNE THROMBOCYTOPENIA (ALCOHOL, HEPARIN, QUININE/QUINIDINE, SULFONAMIDES)
INFECTION/SEPSIS
ACUTE LEUKEMIA
MYELODYSPLASTIC SYNDROME
MALIGNANCY
MEGALOBLASTIC ANEMIA
ISOIMMUNE NEONATAL PURPURA
TRANSFUSION
FACTITIOUS
DIFFERENTIAL DIAGNOSES
DISSEMINATED INTRAVASCULAR COAGULATION
RAPID TESTING FOR HIV
THROMBOTIC THROMBOCYTOPENIC PURPURA (TTP)

LABORATORY DIAGNOSIS
Isolated thrombocytopenia &
Platelet antibodies are key diagonostic method for ITP
Normal or increased number of megakaryocytes on bone marrow examination
FEATURES OF BLEEDING DISORDER
Bleeding time is prolonged
Tests of coagulation are essentially normal
Normal PT
Normal APTT
Normal Fibrinogen Degradation products
Normal levels of coagulation factors

IMAGING STUDIES
A CT SCAN OF THE HEAD IS WARRANTED IF CONCERN EXISTS REGARDING INTRACRANIAL HEMORRHAGE.

FEATURES OF ACUTE AND CHRONIC I.T.P.
I.T.P. Occurs in two forms, namely ACUTE I.T.P. and CHRONIC I.T.P.
ACUTE I.T.P. and CHRONIC I.T.P. differ in incidence, prognosis and therapy.

CLASSIFICATION OF I.T.P

TREATMENT MODALITIES FOR I.T.P.
Bed rest untill Platelet count increase.
Diet – Papaya leaf extract, , Pomegranate, milk, vitA, Cod liver oil.
Common treatment modalities for I.T.P. (platelet count <20,000/microliter or significant mucosal bleeding) :-
Corticosteteroids - Prednisone ( Deltasone, Orasone, Sterapred )
Methylprednisolone ( Solu-Medrol, Depo-Medrol )
IV Immunoglobulins/gamma globulins Carimune NF 400-800 mg/kg
Flebogamma 300-600 mg/kg
Additional immune suppressive agent (rituximab/anti CD 20 antibody)
Splenectomy