Introduction: Pulmonary embolism (PE) is a major cause of morbidity and mortality in the general po-pulation. PE is a clinical condition that occurs due to thrombotic obstruction of the pulmonary arteries or their branches. Among the causes of PE are: major surgery, medullary lesions, neoplasia, chemotherapy, pregnancy, advanced age, bed rest >3 days, immobiliza-tion in sitting position, polycythemia vera end others. Essential thrombocythemia is a chronic myeoloproliferative disease, characterized by sustained megakaryo-cyte proliferation, which causes the increase in circula-ting platelets. Its most common complications include thrombosis and / or hemorrhage.

Methods: We are presenting the case of a 63-year-old patient with a history of post-traumatic splenectomy in 1987, who was admitted on February 15, 2018 in the cardiology department of the „Sf. Ap. Andrei“, Galati. Among the symptoms, patient was presenting: pro-ductive dyspneea, cough with purulent expectoration, chest pain and fever. Upon admission the ECG pathway revealed signs of right sideoverloading; the cardiac ul-trasound noted increased straight cavities and medi-umportal hypertension, which was why thoracic CT with contrast substance revealed suggestive images of thrombus in both pulmonary arteries. Initially, the pa-tient was treated with Fondaparinux 7.5 mg/day and in the incipient phase, patient was hemodynamically sta-ble, without tachycardia or tachypnea.

Results: After a slow favorable progression of approxi-mately 5 days, suddenly the patient’s general condition worsened with severe resting dyspnea, SaO2<90%, ta-chycardia, polypnea, TAs <90 mmHg. Echocardiogra-phy then revealed mobile thrombus in the right side cavities. Doppler pelvic vein ultrasound did not show thrombus at this level. As a response to patient’s symp-toms, the patient has been administered: Thrombolysis with alteplase 100 mg, followed by unfractionated he-parin in continuous parenteral administration and double antibiotherapy (Linezolid and Metronidazole). After this alleged therapeutic option, the patient’s pro-gression was favorable. At that time it was considered that the embolic event was precipitated by postsplenec-tomy thrombocythemia (PLT=623 x 103μL). As of June 2018, the patient is re- hospitalized for pallor, dyspnea with orthopnea, palpitations and melena. Bone narrow biopsy was performed because the platelet count rea-ched approximately 1643 x 103μL after approximately 3 months. As a result of the medulogram, the diagnosis of essential thrombocythemia was confirmed, indica-ting the suspicion that the patient developed pulmo-nary embolism due to the onset of haematological di-sease and specific treatment was initiated. Conclusions: We are facing a patient with multiple causes of thrombocytosis: splenectomy, respiratory in-fection and the onset of haematological disease. With the confirmation of the essential thrombocythemia di-agnosis, the triggering factor of the pulmonary throm-boembolism and the increased risk of the patient to re-peat the embolic event due to the associated hematologic disease was established. In conclusion, pulmonary thromboembolism is a polymorphic pathology, both in terms of clinical presentation and evolution and prog-nosis, which can sometimes be unpredictable.