Poster Session I: Platelets disorders
Cyclic thrombocytopenia (CTP) is a rare platelet disorder characterized by platelet level fluctuations in periodic cycles, each usually spanning from 3-5 weeks and platelet counts ranging from <5 G/l to over 1000 G/l. Since there is no consensus definition of CTP that establishes a clear distinction from immune thrombocytopenia (ITP), most cases of CTP are initially misdiagnosed. Response to standard ITP treatments including corticosteroids, splenectomy, intravenous immunoglobulin or thrombopoietin (TPO) receptor agonists is poor. Management of CTP is not standardized and the pathogenesis is incompletely understood.
To better understand the pathogenesis, course of disease, response to treatment and clinical outcomes of CTP, to identify risk factors and to establish diagnostic and therapeutic strategies.
Between 1991 and 2018, we screened the medical record data of patients treated for isolated thrombocytopenia at the coagulation clinic of a large tertiary hospital in Vienna, Austria. Clinical and laboratory parameters including blood counts, clinical chemistry analyses, results of bone marrow aspiration, comorbidities, co-medications, complications and specific therapies were collected for patients not responding to ITP treatment who had platelet count fluctuations typical for CTP. Data are presented as a descriptive analysis.
We identified 8 patients with CTP and their characteristics are shown in Table 1. The majority (7/8 patients) was female. Except one, all patients were initially diagnosed as having ITP with a time interval ranging from 2 months to 10 years until CTP diagnosis. 4 patients had bleeding at initial diagnosis. In 4 asymptomatic patients, thrombocytopenia was found during routine laboratory testing. 6 patients had hypothyroidism, 1 patient diabetes mellitus type 1 and 1 patient polymyalgia rheumatica.
At initial diagnosis platelet counts ranged between 4 - 46 G/l. Renal and liver function parameters including LDH were normal. Virus serology was negative in all patients. T-cell receptor beta and/or gamma rearrangement was found in 6 patients.
Before CTP diagnosis all patients were treated with oral corticosteroids at standard dose, and received various treatments including intravenous immunoglobulins (5 patients), TPO-receptor agonists (3), and rituximab (4). 5 patients underwent splenectomy. Upon CTP diagnosis, 5 patients were treated with cyclosporine and in 3 patients a watch and wait strategy was pursued.
After diagnosis of CTP, one patient each developed T-cell large granular lymphocytic leukemia and acute myeloid leukemia. One patient suffered from pulmonary embolism during TPO agonist therapy. One patient had intracranial bleeding. Remission of CTP, defined as stable normalization of platelet count, occurred in 5 patients.
In patients with isolated thrombocytopenia and absent response to ITP treatment, CTP has to be considered. CTP predominantly occurs in women and is often associated with hypothyroidism. Transformation into malignant hematological disorders can occur. Of note, remission rates are high.