A fifty-three year old woman presented with symptomatic anemia and hemoglobin of 6.8. She also described progressively worsening fatigue, dyspnea on exertion, weight loss and night sweats over the last three months. Given her history of Crohn’s disease, she had been undergoing extensive outpatient evaluation for gastrointestinal bleeding which had been negative. Her medical history included bilateral renal angiomyolipomas, prior cerebrovascular accidents secondary to non-valvular atrial fibrillation and heart failure with preserved ejection fraction.
Abdominal CT showed active bleeding into an angiomyolipoma in the left kidney, amassing approximately one liter in size. She underwent urgent embolization of the bleeding pseudoaneurysm without complication. The next hospital day she developed fevers, which continued for eight days without evidence of active infectious etiology despite diagnostic workup. She was transferred to the ICU for concern of DIC; once there, new neurological deficits prompted further workup revealing a large middle cerebral artery stroke and large aortic and mitral valve vegetations.
She was initially treated with empiric broad-spectrum antibiotic and antifungal therapy and then tapered to ampicillin-sulbactam and ciprofloxacin. With resolution of aortic and mitral valve vegetations on repeat echocardiography, she was discharged on this regimen for six weeks of total therapy. No microbiological pathogen was identified on extended bacterial and fungal cultures even after three weeks.
Timely diagnosis of infective endocarditis (IE) is important, as morbidity and mortality from the disease can be high. Subacute bacterial endocarditis differs from acute endocarditis as subacute bacterial endocarditis carries a significantly better prognosis. Subacute bacterial endocarditis is generally due to Streptococci species, compared to the highly virulent Staphylococcusspecies causing acute bacterial endocarditis. Diagnosis for IE is made with Duke Clinical Criteria comprising of major criteria (bacteremia, endocardial involvement) and minor criteria (fever, predisposing intravenous drug use, immunologic and vascular phenomenon, fever). Surprisingly, in this patient, only one major and one minor criterion are met, insufficient for a true diagnosis of infective endocarditis. However, the clinical suspicion for IE remained high given the new valvular vegetations and presence of new stroke.
In 20% of patients, blood cultures fail to grow causative microorganism for endocarditis. The most common fastidious organisms are Bartonella species, Coxiella burnetti, and Brucellaspecies. This patient’s immunosuppression with azathioprine also predisposes her for fungal infections, though galactomannan and fungitellin serum assays and fungal cultures were negative.
IE is a notable cause of cardioembolic stroke and occurs in about 17% of cases. The risk for stroke is highest at time of presentation and declined within 1-2 weeks after antimicrobial treatment. Risk factors for stroke included infection with Staph aureus, large valvular vegetations, and immunosuppression. Fungal pathogens also increase the risk of embolization; one review of fungal endocarditis showed a 45% rate of peripheral embolization.
Infective endocarditis may present with negative blood cultures. If clinical suspicion is high for endocarditis, initiation of appropriate antimicrobial therapy may decrease morbidity such as stroke.
To cite this abstract:Moodabagil N, Bowles E, Bhatnagar D. Hacek Me If You Can. Abstract published at Hospital Medicine 2016, March 6-9, San Diego, Calif. Abstract 697. Journal of Hospital Medicine. 2016; 11 (suppl 1). https://www.shmabstracts.com/abstract/hacek-me-if-you-can/. Accessed July 24, 2019.