Background: Biomarkers for the prognosis in severe illness are commonly used. Mean platelet volume (MPV) is an easily accessible haematological parameter which may reflect platelet activation as well as endothelial damage. There are only a few reports concerning the use of this parameter as a biomarker in severe illness.Purpose of the study was the evaluation of MPV as a prognostic biomarker in patients with sepsis.Methods: Patients with suspected sepsis attending the Infectious Diseases wards, medical ICU or interdisciplinary anesthesiology ICU were prospectively enrolled in the analysis. Measures included demographics, medical history as well as clinical and laboratory biomarker determinations on admission and/or first symprtomatic day and day of positive blood culture. Patients were followed having outcomes and biomarkers assessed in the course.Results: 183 patients (66 female) with confirmed sepsis were available for the analysis. Median age was 71 years (range 21-97 years), median BMI was 26.3 kg/m 2 . All had at least one premorbid medical conditions, more than two third had >3 significant pre-existing diseases. Bacteria most commonly detected were S. aureus (54/183) and E. coli (39/183) reflecting the origin of sepsis which mostly were device-related and endocarditis (in 37/183), urogenital (in 35/183) or skin, soft-tissues and bone/joints (27/183), respectively. Unfavourable outcomes (death) at day 30 had 27/183 (14.8%). Patients who died had a higher MPV at admission compared to the survivors (9.6 vs. 9.19 fl, p = 0.031) which increased to an MPV of 11.2 vs. 9.7 fl (p = 0.008) at the time of positive blood culture drawn. Only mean arterial pressure (MAP) at the detection of bacteremia (p = 0.02) and thrombocyte count at bacteremia (p = 0.033) had significant associations with death. Neither temperature, leukocytes, lactate, PCT or CrP had significant associations (all p > 0.1). Receiver operator curve showed AUC for MPV at admission of 0.71 and MPV at bacteremia of 0.68. MAP and thrombocytes at bacteremia had much lower AUC (0.39 and 0.36, respectively).Conclusion: These preliminary data confirm the potential usefulness of MPV as an easily accessible prognostic marker in sepsis. Further studies are required to confirm our results.

High grade fever in the context of Staphylococcus aureus bacteremia led to hospital admission of a 79 year old male patient. A covered perforation of the ascending aorta resulted in the formation of a pseudoaneurysm which was complicated by superinfection caused by hematogenic spread of Staphylococcus aureus. The infected pseudoaneurysm found per continuitatem contact to the pericardium and resulted in bacterial pericarditis. Antibiotic pretreatment was followed by operation with a complex procedure including resection of pseudoaneurysm and suture closure of the perforation site.