Diagnosis of thrombocytopenic purpura

Laboratory diagnosis of thrombocytopenic purpura

In a laboratory examination, thrombocytopenia is less than 100,000 / mm ³, an increase in the average platelet count (MPV) from an automatic blood analyzer to 8.9 ± 1.5 μm ³.

Classification of platelet diseases depending on their size

MPV upgraded	MPV norm (7.1 μm)	MPV reduced
ITP and other conditions with increased production and consumption of platelets, including DIC-syndrome	Conditions in which the bone marrow is malocular or affected by malignant diseases	Wiskott-Aldrich Syndrome
The Maya-Hegglin anomaly	-	Disease of accumulation
Alport Syndrome	-	Iron-deficiency anemia
Mucopolysaccharidosis, a syndrome of "gray" platelets
Syndrome of "leaky" platelets ("Swiss" cheese)	-	-
The Montreal Platelet Syndrome	-	-
Syndrome Bernard-Soulier	-	TAR-Syndrome

In peripheral blood in patients with idiopathic thrombocytopenic purpura, in addition to thrombocytopenia, there may be mild eosinophilia. With severe blood loss, anemia develops.

In the bone marrow puncture, which is carried out to exclude other oncohematological diseases, irritation of the megakaryocyte germ, weak "loosening" of platelets in normal erythroid and myeloid sprouts are found. Part of the patients exhibit mild eosinophilia.

In the study of the coagulation profile, optional for standard idiopathic thrombocytopenic purpura, an increase in bleeding time, a decrease or absence of clot retraction, a violation of prothrombin utilization at normal fibrinogen levels, prothrombin time and activated partial thromboplastin time are revealed.

Laboratory studies in patients with thrombocytopenia include:

• a general blood test with a smear and a determination of the number of platelets;
• examination of bone marrow punctate;
• blood analysis for ANF, anti-DNA, complement fraction of C3, C4, antiplatelet antibodies, plasma glycocalicin level, Coombs test;
• determination of prothrombin time, activated partial thromboplastin time, fibrinogen level, fibrinogen degradation products;
• Determination of urea, blood creatinine, liver samples;
• blood test for opportunistic infections (HIV, Epstein-Barr virus, parvovirus);
• Exclusion of secondary forms of thrombocytopenia.

The main criteria for diagnosing idiopathic thrombocytopenic purpura are:

• absence of clinical signs of systemic and oncohematological diseases;
• isolated thrombocytopenia with normal number of erythrocytes and leukocytes;
• normal or increased number of megakaryocytes in the bone marrow with normal erythroid and myeloid elements;
• Exclusion of secondary forms of thrombocytopenia in hypersplenism, micro-angiopathic hemolytic anemia, DIC syndrome, drug-induced thrombocytopenia, systemic lupus erythematosus, viral infections (Epstein-Barr virus, HIV, parvovirus).

[1], [2], [3], [4], [5], [6], [7], [8], [9]