Purpura mimicking posttransfusion purpura

Abstract

A 72-year-old woman with advanced liver cirrhosis, high blood pressure, and severe aortic stenosis had a gastrointestinal bleeding and received 2 units of RBCs upon hospital arrival. While receiving the second unit of RBCs, she had nausea and vomited. During the adverse reaction workup, high blood pressure (200/120 mmHg) was detected and purpura appeared on both forearms and hands, especially on the left limb (see figure: left—picture of both hands on which petechiae are more intense on the left hand and forearm; right—purpura on the left forearm and hand [note that areas where the patient wore rings show no petechiae]). The resident in charge diagnosed a posttransfusion purpura (PTP) and called the transfusion service. The hematologist diagnosed a purpura due to the pressure cuff used to measure arterial pressure, in an already thrombocytopenic patient (59 × 10/L). Posttransfusion purpura is a rare condition that usually appears 5 to 10 days after transfusion in women sensitized by pregnancy or transfusion, due to antibodies against HPA-1a PLT antigens. Thrombocytopenia is usually severe and bleeding can be seen. In our case, although the patient had been pregnant and received transfusions, other data were against PTP: purpura appeared immediately after transfusion, and PLT numbers had not changed from previous controls and stayed stable until discharge. The patient suffered no further bleeding episodes and petechiae disappeared over time. Awareness of adverse transfusion reactions is crucial when prescribing transfusions. The patient’s background, timing of the reaction, signs, and symptoms should be taken into account. PTP should be suspected when studying an unexpected thrombocytopenia and is confirmed by the presence of PLT antibodies and the lack of the antigen in the patient. Why the patient’s PLTs are also destroyed is still unknown.