PP-097 Mild Hypereosinophilia During Warfarin Therapy: Report of Two Cases and a Short Review of the Literature

A B S T R Objective: Warfarin is widely used in clinical practice. Its most known side effects are hemorrhage and skin adverse reactions.We report two cases in whom mild eosinophilia appeared after initiation of warfarin therapy. Methods-Results: A 43-year-old man presented with dyspnea, hemoptisis and chest pain. The final diagnosis was acute pulmonary thromboembolism following acute deep venous thrombosis(DVT). He was treated with low molecular weight heparin (LMWH) and warfarin. The eosinophil count was normal before initiation of warfarin. However the eosinophil ratio gradually increased to 10% (800/mm) in the first week. The examination for ova and parasites was negative. Blood biochemistry and several kinds of allergen tests were normal. IgE level was slightly increased. The INR value of the patient increased very quickly and daily need was 1.25 mg to stabilize INR between 2-3. With 8.75 mg/week dosing, the eosinophil count was stabilized at 600/mm. The patient was heterozygos for factor V Leiden and he was experiencing a second attack of DVT. Therefore he had a lifelong oral anticoagulation (OAC) therapy indication. A second 55-year-old male patient presented with rapid ventricular response lone atrial fibrillation(AF). During discharge 27.5 mg/week warfarin was started. On his first control 10 days later,the INR was 17. He was hospitalized to receive vitamin K and fresh frozen plasma. Hemogrambefore AF attackwas normal, but when hewas hospitalized for warfarin overdose he had 10% (appr. 800/mm) eosinophils in the peripheral blood.Allergy and parasites testswere negative.He was not on any medications other than warfarin. During discharge we started 20mg/day rivaroxaban and 25 mg carvediolol. The eosinophil count decreased to 400/mm one month after cessation of warfarin. Conclusions: Besides hemorrhage, skin adverse reactions, hipersensitivity or liver disorders, there are reports that warfarin can cause eosinophilia.Normal eosinophil count is up to 600 cells/mm.Mild eosinophilia is 600-1500 eosinophils, moderate is 1500-5000 and severe is 5000 eosinophils per microlitre. Drugs can be responsible for eosinophilia. The most commondrugs are aspirin, penicillin, gold compoundsor sulfa agents. In 1981, first report on severe hypereosinophilia related with warfarin use was published. Similar several cases followed this index report. The common point in our two patients was a propensity for warfarin overdose.The approach to this clinical entity is not known. Warfarin therapy should be ceased in symptomatic severe hypereosinophilia. In one patient we switched to rivaroxaban, but in the other we continued warfarin due to economical issues. NewOACs are not an alternative for all patients,such as those having metallic heart valves. We should be aware of this adverse effect of warfarin. We can periodically check hemogram together with hemostasis panel, because the eosinophil counts can increase to deleterious numbers.