Indian J Pediatr DOI 10.1007/s12098-014-1369-8
SCIENTIFIC LETTER
Pseudothrombocytopenia in a Child with Dengue Prakash Vaidya & Rohini Venkataraman
Received: 21 August 2013 / Accepted: 30 January 2014 # Dr. K C Chaudhuri Foundation 2014
To the Editor: Thrombocytopenia is a known feature of Dengue infection and blood samples for platelet counts are usually collected in ethylene diamine tetra-acetic acid (EDTA). We recently managed a patient of dengue with EDTA-PTCP (pseudothrombocytopenia). A 5-y-old boy presented with one day history of fever with rigors. His counts were: WBC 8,000/μL, Platelets 19,000/μL, Hb 12.9 g/dL. Malarial parasite was negative. Dengue NS1 antigen was positive. The child was hospitalized for further management. After admission he continued to have fever but was hemodynamically stable with no rash, petechiae or evidence of capillary leak. His platelet counts in EDTA progressively dropped to 5000/μL (Fig. 1). However, the Hematocrit and WBC count surprisingly remained unaltered. We repeated the platelet count by a finger-prick peripheral smear and also sent samples in EDTA, Citrate and Heparin. Fresh smears in EDTA showed no clumps but smears done at 10 min from the EDTA sample showed large clumps (Fig. 2) and a platelet count of 5,000/μL. Platelet counts done at 10 min intervals on Coulter from the EDTA blood showed progressively reducing platelet counts. Platelet counts from Citrate and Heparin samples were 85,000/μL. This confirmed our suspicion of EDTA–dependent pseudothrombocytopenia.
The child made an uneventful recovery and on follow up after 3 mo, platelet count in EDTA was normal. EDTA-induced pseudothrombocytopenia is the phenomenon of in vitro platelet clumping due to autoantibodies that recognize platelet antigens modified by EDTA. This results in a spuriously low platelet count on automated cell counters. The phenomenon is reported both in healthy subjects and patients with various diseases and its incidence has been reported to be 0.09 to 0.21 % [1]. No abnormalities of platelet function are described with EDTA dependent PTCP [2]. EDTA-PTCP has been reported to appear in severely ill patients, autoimmune, neoplastic, atherosclerosisrelated, liver diseases, burns, sepsis, infectious diseases and cardiac surgery [3–5]. In some studies, EDTAPTCP appeared during hospitalization, indicating that the antibody is an acquired one [3]. A literature search did not reveal EDTA- PTCP appearing in a case of Dengue, hence this communication.
20000 15000 Platelet Count / 10000 Cu. mm 5000 0
P. Vaidya (*) : R. Venkataraman Department of Pediatrics, Fortis Hospital, Mulund, Mumbai, Maharashtra 400080, India e-mail: [email protected]
Day 1
Day 2
Day 3
Day 4
Day of admission
Fig. 1 Graph showing the decreasing trend of platelet counts
Day 5
Indian J Pediatr Conflict of Interest None.
Role of Funding Source None.
Large platelet clumping
Fig. 2 Smear from EDTA sample at 10 min showing platelet clumping in the child with EDTA-PTCP
This highlights the importance of confirming all cases of thrombocytopenia, especially in dengue fever, with peripheral blood smear from finger-prick capillary blood. Acknowledgments We would like to acknowledge the help received from Dr. Supriya Dutta, Department of Pathology, Fortis Hospital, Mulund, Mumbai in managing this case.
References 1. Yoneyama A, Nakhara K. EDTA-dependent pseudothrombocytopenia— differentiation from true thrombocytopenia. Nihon Rinsho Jpn J Clin Med. 2003;61:569–74. 2. Casonato A, Bertomoro A, Pontara E, Dannhauser D, Lazzare AR, Girolami A. EDTA dependent pseudothrombocytopenia caused by antibodies against the cytoadhesive receptor of platelet gpIIB-III. J Clin Pathol. 1994;47:625–30. 3. Berkman N, Michaeli Y, Or R, Eldor A. EDTA-dependent pseudothrombocytopenia: A clinical study of 18 patients and a review of the literature. Am J Hematol. 1991;36:195–201. 4. Bragagni G, Bianconcini G, Brogna R, Zoli G. Pseudothrombocytopenia: Clinical comment on 37 cases. Minerva Med. 2001;92:13–7. 5. Carrillo-Esper R, Contreras-Domínguez V. Pseudothrombocytopenia induced by ethylenediaminetetraacetic acid in burned patients. Cir Cir. 2004;72:335–8.
SCIENTIFIC LETTER
Pseudothrombocytopenia in a Child with Dengue Prakash Vaidya & Rohini Venkataraman
Received: 21 August 2013 / Accepted: 30 January 2014 # Dr. K C Chaudhuri Foundation 2014
To the Editor: Thrombocytopenia is a known feature of Dengue infection and blood samples for platelet counts are usually collected in ethylene diamine tetra-acetic acid (EDTA). We recently managed a patient of dengue with EDTA-PTCP (pseudothrombocytopenia). A 5-y-old boy presented with one day history of fever with rigors. His counts were: WBC 8,000/μL, Platelets 19,000/μL, Hb 12.9 g/dL. Malarial parasite was negative. Dengue NS1 antigen was positive. The child was hospitalized for further management. After admission he continued to have fever but was hemodynamically stable with no rash, petechiae or evidence of capillary leak. His platelet counts in EDTA progressively dropped to 5000/μL (Fig. 1). However, the Hematocrit and WBC count surprisingly remained unaltered. We repeated the platelet count by a finger-prick peripheral smear and also sent samples in EDTA, Citrate and Heparin. Fresh smears in EDTA showed no clumps but smears done at 10 min from the EDTA sample showed large clumps (Fig. 2) and a platelet count of 5,000/μL. Platelet counts done at 10 min intervals on Coulter from the EDTA blood showed progressively reducing platelet counts. Platelet counts from Citrate and Heparin samples were 85,000/μL. This confirmed our suspicion of EDTA–dependent pseudothrombocytopenia.
The child made an uneventful recovery and on follow up after 3 mo, platelet count in EDTA was normal. EDTA-induced pseudothrombocytopenia is the phenomenon of in vitro platelet clumping due to autoantibodies that recognize platelet antigens modified by EDTA. This results in a spuriously low platelet count on automated cell counters. The phenomenon is reported both in healthy subjects and patients with various diseases and its incidence has been reported to be 0.09 to 0.21 % [1]. No abnormalities of platelet function are described with EDTA dependent PTCP [2]. EDTA-PTCP has been reported to appear in severely ill patients, autoimmune, neoplastic, atherosclerosisrelated, liver diseases, burns, sepsis, infectious diseases and cardiac surgery [3–5]. In some studies, EDTAPTCP appeared during hospitalization, indicating that the antibody is an acquired one [3]. A literature search did not reveal EDTA- PTCP appearing in a case of Dengue, hence this communication.
20000 15000 Platelet Count / 10000 Cu. mm 5000 0
P. Vaidya (*) : R. Venkataraman Department of Pediatrics, Fortis Hospital, Mulund, Mumbai, Maharashtra 400080, India e-mail: [email protected]
Day 1
Day 2
Day 3
Day 4
Day of admission
Fig. 1 Graph showing the decreasing trend of platelet counts
Day 5
Indian J Pediatr Conflict of Interest None.
Role of Funding Source None.
Large platelet clumping
Fig. 2 Smear from EDTA sample at 10 min showing platelet clumping in the child with EDTA-PTCP
This highlights the importance of confirming all cases of thrombocytopenia, especially in dengue fever, with peripheral blood smear from finger-prick capillary blood. Acknowledgments We would like to acknowledge the help received from Dr. Supriya Dutta, Department of Pathology, Fortis Hospital, Mulund, Mumbai in managing this case.
References 1. Yoneyama A, Nakhara K. EDTA-dependent pseudothrombocytopenia— differentiation from true thrombocytopenia. Nihon Rinsho Jpn J Clin Med. 2003;61:569–74. 2. Casonato A, Bertomoro A, Pontara E, Dannhauser D, Lazzare AR, Girolami A. EDTA dependent pseudothrombocytopenia caused by antibodies against the cytoadhesive receptor of platelet gpIIB-III. J Clin Pathol. 1994;47:625–30. 3. Berkman N, Michaeli Y, Or R, Eldor A. EDTA-dependent pseudothrombocytopenia: A clinical study of 18 patients and a review of the literature. Am J Hematol. 1991;36:195–201. 4. Bragagni G, Bianconcini G, Brogna R, Zoli G. Pseudothrombocytopenia: Clinical comment on 37 cases. Minerva Med. 2001;92:13–7. 5. Carrillo-Esper R, Contreras-Domínguez V. Pseudothrombocytopenia induced by ethylenediaminetetraacetic acid in burned patients. Cir Cir. 2004;72:335–8.
