Curious Case of Profound Thrombocytopenia in a Pregnant Woman

Abstract

Introduction:Pseudo-thrombocytopenia (PTCP) is a benign artifact which generates anxiety in the patients and physicians resulting in unnecessary investigations. We report a case with profound artefactual thrombocytopenia.Case:A 31-years-old female in 38th week of gestation was referred to hematology clinic for evaluation of a platelet count of 48x109/L. A month ago platelet count was 102x109/L. She denied any symptoms. Examination was normal with no ecchymosis or petechiae. Laboratory work showed a white cell count of 11.2x109/L, hemoglobin 10.3g/L, platelet count 8x109/L and no hemolysis. Peripheral blood smear showed numerous platelet clumps (Figure 1). Estimated manual platelet count was 200x109/L. To our surprise clumps and low machine count were seen in samples drawn in sodium citrate and heparin tubes as well.Discussion:Ethylenediaminetetra-acetic acid (EDTA) dependent PTCP is a rare phenomenon with incidence of 0.09%-0.21% in general population (1). It is present in healthy subjects (2), severely ill patients with sepsis (3), autoimmune, neoplastic and liver diseases (4). PTCP may persist for 15-20 years without any clinical manifestations (5). Platelet aggregation in PTCP is due to anti-platelet antibody mediated in-vitro activation via GPIIb receptors (6). Antibodies may be IgG, IgA or IgM (5). It may be seen in samples drawn in citrate (5) heparin (7) and sodium-oxalate (8). One should suspect PTCP when there is fall in platelet count (usually <100x109/L), time-dependent spurious elevation of white cells(9), a normal mean platelet volume (4) or microscopic detection of platelet aggregates (1) in a patient without clinical manifestations. There is a rare report that addition of amikacin could inhibit and dissociate pseudo platelet aggregation in multianticoagulant-dependent pseudo-thrombocytopenia and EDTA-induced pseudo-thrombocytopenia (10). Early identifications is extremely essential when therapeutic decision making hinges on platelet count viz. management of acute myocardial infarction (11).Use of samples at 37°C (2), ammonium oxalate (5, 7), addition of amikacin and peripheral smear review may help in complicated cases.