ENOXAPERIN-INDUCED THROMBOCYTOPENIA LEADING TO SADDLES EMBOLISM

Abstract

SESSION TITLE: Medical Student/Resident Pulmonary Vascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Heparin-induced thrombocytopenia ( HIT) is a life-threatening complication most commonly caused by unfractionated heparin. We present a rare case of enoxaparin induced HIT leading to saddle pulmonary embolism during medical treatment of femur fracture repair on prophylactic enoxaparin. CASE PRESENTATION: A 69-year-old Caucasian female presented in the emergency department with the chief complaint of shortness of breath. Shortness of breath was sudden, associated with palpitation. Her past medical history was significant for recently treated femur fracture 10 days before presentation and she was discharged on prophylactic enoxaparin 40mg daily for the prevention of DVT. On exam, her blood pressure was 107/63 mmHg and heart rate at 107 beats per minute. Initial investigation revealed thrombocytopenia with platelet count at 50 × 103 cells/μl dropped from 157 × 103 cells/μl after starting on the enoxaparin 10 days ago. X-ray chest was normal but because of high Wells score patient underwent CT angiography of chest, which revealed bilateral saddle pulmonary embolism. Her troponin was elevated at 1.4 ng/ml with elevated pro BNP at 2304 pg/ml. Her echocardiogram showed the right heart stain pattern. Interventional radiology was consulted and the patient underwent mechanical thrombectomy for submissive pulmonary embolism. Because of the high HIT score, enoxaparin was stopped, and the patient started on argatroban. Her labs for heparin-induced thrombocytopenia were sent which came out positive for PF4 antibodies and later high positive serotonin release assay. After ruling out systemic causes of thrombocytopenia and later laboratory confirmation for HIT, our patient was meeting the criteria for HIT secondary to enoxaparin because of 1. new thrombus formation in pulmonary vein 2. > 50% drop of platelets on admission day 3. positive PF4 and serotonin release assay. 4. heparin naive status. The patient later bridged with warfarin for pulmonary embolism for 3 months. She had an uneventful recovery with complete recovery of platelet counts to normal. DISCUSSION: Thrombocytopenia because of heparin therapy was first described in the late 1960s. The diagnosis of HIT includes a 50% fall in platelet count, beginning between five and 14 days after initial exposure to heparin of any dose or type, and detection of the HIT antibody against the PF4–heparin complex is necessary. We diagnosed enoxaparin-induced thrombocytopenia because of the clinical features, the patient’s heparin-naïve state, and the laboratory finding of antibodies against PF4 and heparin complexes. CONCLUSIONS: We report our experience with enoxaparin-induced thrombocytopenia during the medical treatment of femur fracture DVT prophylaxis. Although rare, LMWH such as enoxaparin may induce thrombocytopenia, which could be a life-threatening complication. Paying close attention to this rare side effect of enoxaparin can save someone's life. Reference #1: Kelton JG, Warkentin TE. Heparin-induced thrombocytopenia: a historical perspective. Blood. 2008;112:2607–2616. [PubMed] [Google Scholar] Reference #2: Cuker A. Recent advances in heparin-induced thrombocytopenia. Curr Opin Hematol. 2011;18:315–322. [PubMed] [Google Scholar] Reference #3: Ahmed I, Majeed A, Powell R. Heparin-induced thrombocytopenia: diagnosis and management update. Postgrad Med J. 2007;83:575–582. [PMC free article] [PubMed] [Google Scholar] DISCLOSURES: No relevant relationships by Muhammad Aamir, source=Web Response No relevant relationships by Muhammad Afzal, source=Web Response No relevant relationships by Fatima Ayub, source=Web Response No relevant relationships by Adil Cheema, source=Web Response No relevant relationships by Muhammad Talha Khan, source=Web Response No relevant relationships by Danish Thameem, source=Web Response