Lemierre´s syndrome is a rare but serious infection caused by bacteria attacking the lymph nodes of the neck and causing blood clots to form in the large veins of the neck, whereas mediastinistis is an acute inflammation of the mediastinum. (1, 2) The presence of enlarged lymph nodes in the mediastinum on an X-ray of the lungs or a CT of the thorax leads to the diagnosis.

In this case report we describe the case of 40-year-old patient who was admitted to the Cardiology Department of the Šibenik General Hospital due to swelling and pain in the left side of the neck, as well as fever. The course of the patient’s stay in Šibenik General Hospital, as well as the transfer and course of the patient’s stay in University Hospital Centre Split, where the patient was transferred due to disturbed general condition, hemodynamic instability, and worsening of inflammatory parameters, is shown. All diagnostic procedures for determining the cause of the patient’s condition, as well as all therapeutic procedures, are also discussed. Deep vein thrombosis of the cephalic vein, pericardium effusion, and bilateral pleural effusion were all confirmed by diagnostic tests. Can we say with certainty that the resulting clinical picture is post-COVID-19 because the patient overcame a moderate clinical picture of SARS-CoV-2 virus infection a month before the onset of these symptoms?