We report the case of a 79-year-old patient, admitted to the department of infectious diseases at Bretagne Sud Hospital Center for a right calcaneal osteitis, complicated by a pacemaker leads infectious endocarditis. Meticillin sensitive Staphylococcus aureus was documented by blood culture. Antibiotic treatment was established using intravenous cefazolin for an initial 6 weeks period. Prothrombin time (PT) decreased as well as vitamin K dependent factors, without anticoagulation therapy, at day 7 of cefazolin treatment. After bleeding occurred on calcaneal osteitis, the VAC® therapy system was removed and intravenous vitamin K 10 mg (then 5 mg per day for 5 days per os) was administered. Vitamin K allowed PT and vitamin K dependent factors to return to normal values. Literature review does not explicitly mention the effects on vitamin K dependent factors after cefazolin administration. Four severe haemorrhagic episodes under cefazolin have been declared in France so far since February 2017. The goal of this article is to alert clinicians and clinical pathologists from the potential appearance of coagulation disorders in patients treated by cefazolin.
Keywords: cefazolin; hypoprothrombinemia; monitoring; vitamin K.