The Frequency of Primary Immune Thrombocytopenia (idiopathic thrombocytopenic purpura) in Patients with Isolated Thrombocytopenia
Authors: Melikyan Anait L. , Egorova Elena K , Pustovaya Elena I , Kolosheynova Tamara I , Subortseva Irina N , Gilyazitdinova Elena A , Savchenko Valeriy G. 
Published: October 2019

Abstract
CONTEXT: Many hematological and non-hematological diseases can be hidden under the mask of isolated thrombocytopenia. The choice of therapeutic tactics is determinated by correct diagnosis.
OBJECTIVE: to define the frequency of occurrence of primary immune thrombocytopenia (idiopathic thrombocytopenic purpura-ITP) in the group of patients with isolated thrombocytopenia.
Materials and methods: We analysed clinical and laboratory data of 301 patients who applied to the outpatient department of National Research Center for hematology, Russian Federation with thrombocytopenia of unspecified origin. The first group is 183 patients who applied for the first time. The second group is 118 patients with long history of ITP. All patients were examined according to the extended differential diagnostic protocol used in isolated thrombocytopenia and based on international and National clinical recommendations for the diagnosis and treatment of ITP in adults.
Results: Median age of patients in both groups was 36 years, male/female ratio in group 1 was 1:2, in group 2 - 1:4. In group 1, the count of platelets in the blood was more than 50*109/l in 87% of cases, while in the second group, in most cases (94%), there was a decrease in the count of platelets <50*109/l. Among the patients of the first group, haemorrhagic syndrome was absent in 50% of cases, even with platelet count less than 50*109/l. In the second group, 88% of patients complained of haemorrhages on the skin and mucosa, in 2% of cases life-threatening bleeding (uterine and gastrointestinal) developed (table 1). The examination carried out according to the protocol allowed to establish the diagnosis of ITP in group 1 in 88 (48%) patients, in group 2 in 100 (85%). Thus, the ratio of primary and secondary thrombocytopenia in group 1 was 1:1, in group 2 - 6:1. (fig. 1). The causes of secondary thrombocytopenia in group 1 were: increased consumption syndrome with thrombogenic complications in 16 (9%) patients, autoimmune diseases, occurring with isolated thrombocytopenia in 13 (7%) cases, virus-associated thrombocytopenia in 12 (7%) patients, drug-induced thrombocytopenia in 8 (4%) patients with diseases of the cardiovascular system, long-taking anticoagulants and disaggregants, in 7 (4%) cases of chronic viral hepatitis C, in 4 (2%) - liver cirrhosis of non-viral etiology, in 4 (2%) HIV infection, in 4 (2%) lymphoproliferative disease, in 2 (1%) acute leukemia, in 3 (2%) cases myelodysplastic syndrome (MDS), 14 (8%) women were diagnosed with gestational thrombocytopenia, EDTA-associated false thrombocytopenia was detected in 8 (4%) patients. Repeated examination of patients of the second group was carried out in the following cases: early relapse, resistance to corticosteroid therapy or loss of response after any line of therapy, incompliance of haemorrhagic syndrome with the count of platelets, the presence of thrombosis in the history, causing doubts in the diagnosis of ITP. The diagnosis of ITP in this group was changed to antiphospholipid syndrome in 4 patients, MDS in 4 cases, in 2 - systemic lupus erythematosus, in 3 - primary immunodeficiency and 2 patients, aged 40 and 44 years were found to have a genetic abnormality - abnormality Meya-Hegglina and thrombasthenia Glanzmann. A comparison of the number of patients diagnosed with ITP and secondary thrombocytopenia by age groups showed that secondary thrombocytopenia are more common at the age of 60 years (38% versus 19%, respectively) (Fig. 2).
Conclusion: This study clearly presents a variety of hematological and non-hematological diseases occurring with isolated thrombocytopenia, which indicates the ambiguity of such concepts as the symptom of isolated thrombocytopenia and primary immune thrombocytopenia and requires a complete examination not only in the onset of the disease, but also in the recurrence of ITP.

Disclosures
No relevant conflicts of interest to declare.