Septic shock from osteomyelitis on wound post-cardiac surgery: A case report

64-year-old patient undergoing aortic valve replacement surgery with bioprosthesis (Edwards Inspiris Resilia 23) and double coronary artery bypass grafting (LIMA on LAD and GSV on RCA) in the previous three months;came to our observation for onset of fever up to 39.5 C, hypotension, nausea and retching associated with dyspnoea;negative Sars-Cov-2 PCR;on suspicion of endocarditis he was admitted to our ward. He was treated in the acute phases with inotropic support with norepinephrine, fluids and broad spectrum antibiotic therapy. The need for abundant hydration in the first days led to a symptomatic heart failure treated with IV diuretic therapy first then orally. In the transthoracic echocardiogram, no vegetations were documented on the aortic prosthesis, regularly functioning, nor on the other valves;this data was subsequently confirmed by the transesophageal echocardiogram. The blood cultures were positive for Staphylococcus Aureus MSSA for which therapy with Oxacillin was set according to infectious disease specialist indication. A few days after admission an erythema of the sternal surgical wound with abscess appeared. The reference cardiac surgeon was contacted and he proceeded to clean the wound;swabs and biopsy culture were performed and confirmed the presence of the Staphylococcus;chest CT scan showed lesions inside the sternal manubrium suggestive of osteomilitis (DSWI). Antibiotic therapy was continued as previously suggested with Oxacillin for 6 weeks and a single dose infusion of Dalbavancin. During the first days, a single episode of total AV block with a frequency of 35/40 bpm was detected at the telemetry control;actually we are oriented on a sinus node disease requiring a close monitoring;in fact, we have currently opted to postpone a possible pacemaker implantation after the resolution of the septic status. Although uncommon, sternal wound infections are potentially life-threatening complications of cardiac surgery. They are associated with prolonged hospitalizations, increased cost of care, significant morbidity and increased short- and long-term mortality. Although most literature reports that the mean interval between initial cardiac surgery and diagnosis of DSWI is about 14 days, there have been cases of delayed presentations of DSWI.