it is found in up to 40% of patients at surgery or autopsy.1 ) the aortic valve and its adjacent ring are more susceptible to abscess formation and paravalvular extension compared to the mitral valve.1 ) we report a case of staphylococcal endocarditis involving the tricuspid valve complicated by a para - aortic abscess that ruptured into the aortic sinus diagnosed by trans - thoracic echocardiogram .
his medical history was unremarkable , except left ankle trauma three months prior to presentation . on admission , the blood pressure was 100/50 mmhg , pulse rate was 111/min , respiratory rate was 22/min and body temperature was 39.7. auscultation revealed clear breathing sounds and a faint diastolic regurgitant murmur ( 1 - 2/6 ) at the left sternal border .
in addition , reddish , painful left ankle edema , suggestive of cellulitis in addition to small erythematous macular lesions suggestive of janeway lesions on the soles were present .
electrocardiogram showed sinus tachycardia ( 107 beats / minute ) without st - t segment abnormality .
laboratory tests revealed a white blood cell count of 17,000/l with elevated neutrophils ( 85.4% ) , a hemoglobin level of 13.2 g / dl , an elevated erythrocyte sedimentation rate ( esr ) ( 23 mm / hour ) , a c - reactive protein 10.48 mg / dl and abnormal liver function with aspartate aminotransferase / alanine aminotransferase of 39/66 iu /
1 ) revealed mild aortic regurgitation , bicuspid aortic valve and an oval echolucent area near the aortic valve adjacent to the right bicuspid aortic valve commissure with direct communication to the aortic sinus .
an echolucent cavity was visible on the right side of the aortic valve annulus , and was thought to represent paravalvular ring abscess .
a diastolic color flow jet into the abscess cavity indicated a communication with the aortic sinus .
examination of the tricuspid valve demonstrated a 1.4 cm mobile vegetation on the septal leaflet of the tricuspid valve associated with trivial tricuspid regurgitation . however , cardiac systolic function was normal with a 63% ejection fraction .
transesophageal echocardiography was performed on the fourth hospital day to further investigate the oval echolucent area near the aortic valve , which confirmed a bicuspid aortic valve along with a para - aortic abscess that communicated directly with the aortic sinus ( fig .
2 ) . computed tomography scan of the abdomen demonstrated multiple hypodense lesions in the spleen and the left kidney , considered to be abscesses secondary to septic emboli .
staphylococcus aureus ( s. aureus ) , sensitive to ciprofloxacin , gentamicin , oxacillin , rifampin , teicoplanin , tetracycline , trimthoprim / sulfamethoxazole , and vancomycin , was isolated from peripheral blood cultures according to susceptibility test performed by the disc diffusion method .
ultimately , a diagnosis of acute staphylococcal endocarditis was made according to the duke criteria , which included three positive blood culture results of s. aureus , the presence of vegetation on the tricuspid valve and para - aortic abscess as demonstrated by echocardiogram , in addition to clinical and laboratory features , such as left ankle cellulitis , fever , and janeway lesion .
the patient was empirically treated with a combination of nafcillin ( 1 g/12 h ) and gentamicin ( 60 mg/8 h ) before blood culture results were known . over the subsequent 48 hours
, the patient 's cellulitis improved markedly as evidenced by reducing erythema , swelling , and pain of the left ankle .
initially , the patient responded well , but after 7 days of intravenous antibiotic administration , laboratory results showed signs of increasing inflammation . a new rise in leukocytes counts from 9,400/l to 10,000/l , with elevated neutrophils from 73% to 79% , was observed .
esr increased from 21 mm / h to 24 mm / h at the time . because the infection site was critical , we replaced intravenous nafcillin with intravenous vancomycin ( 1 g/12 h ) and persisted with gentamicin ( 60 mg/8 h ) , with the suspicion of nafcillin resistance .
repeat transthoracic echocardiography demonstrated bicuspid aortic valve along with a persistent para - aortic abscess communicating with the aortic sinus .
the size of tricuspid valve vegetation reduced from 15 mm to 7 mm after the first 14 days of antibiotic therapy . repeated blood cultures were negative during antibiotic therapy .
however , vancomycin therapy was discontinued after 21 days due to leukopenia ( leukocyte count of 2,900/l and neutrophil count of 14.4% ) .
antimicrobial therapy was discontinued because the patient showed no signs of active infection , and repeated blood cultures were negative .
one week after discontinuing antibiotic therapy , blood analysis demonstrated a normal leukocyte count of 7,600/l , a neutrophil of 66.6% and an esr of 6 mm / h .
ultimately , the patient received 4 weeks of antibiotics with various regimens : nafcillin / gentamicin for 1 week followed by vancomycin / gentamicin for 1 week , followed by 2 weeks of vancomycin therapy .
the patient made a recovery , as the tricuspid valve vegetation disappeared and the abscess cavity showed no significant change in size on the follow - up echocardiogram performed one month after discharge .
staphylococcal tricuspid valve endocarditis with para - aortic abscess in a patient with bicuspid aortic valve is rare .
it is quite unusual for coagulase - negative staphylococci to cause endocarditis in a young , otherwise healthy person who was not an intravenous drug user , and who had no other risk factors predisposing to infective endocarditis .
perivalvular abscess is an ominous development in patients with endocarditis , because it is associated with valvular and perivalvular destruction , leading to serious complications , such as heart block , pericarditis and acute valvular insufficiency.2 ) in patients with native valve endocarditis , the risk is increased when the valve is bicuspid .
ellis et al.3 ) described signs suggestive of the presence of perivalvular abscesses on transthoracic echocardiogram , e.g. , rocking motion of the prosthetic valve , aneurysm of the sinus of valsalva , increased subvalvular intraventricular septum thickness ( 13 mm ) , and thickening of the aortic root wall ( 10 mm ) .
if any of these abnormalities is seen on transthoracic echocardiogram , or if there are clinical manifestations of abscess , transesophageal echocardiography is indicated .
it remains unclear whether detection of root abscess in the disease course of aortic valve endocarditis is an indication for surgery .
surgery in patients with active infection and perivalvular abscess carries a high risk of death , and is associated with significant risk of recurrent infection and periprosthetic leak postoperatively.4 - 8 ) due to the patients ' preoperative conditions secondary to sepsis , treatment of complex aortic valve endocarditis is a surgical challenge , with a reported mortality rate that ranges from 9% to 23%.9 ) annular abscesses or intracardiac fistulae increase the technical difficulties and risks associated with surgical treatment.10 ) the long - term outcome of these patients has not been well defined.7)8 ) a small number of patients with periannular extension of infection or myocardial abscess may be treated successfully without surgical intervention.11)12 ) these patients potentially include those who have smaller ( < 1 cm ) abscesses , and who do not have complications such as heart block , echocardiographic evidence of progression of abscess during therapy , valvular dehiscence or insufficiency .
cases of successful medical treatment of perivalvular abscess have been reported,11)13 - 15 ) but there have been no published series of consecutive patients and no comparison has been conducted with surgically treated patients .
surgical versus conservative treatment in patients with infective endocarditis and paravalvular abscess were associated with similar survival in another study.2 ) in a retrospective study of 233 cases of perivalvular abscess from 42 french hospitals over a 5-year period , medically treated patients who constituted 9% of the study population , had a survival rate similar to surgically treated patients.8 ) the findings of these study suggest that the main impetus for surgery is severe heart failure despite medical treatment , and that surgery may be deferred or avoided in patients whose heart failure is well controlled.2)8 ) in most patients , the abscess led to aortic pseudoaneurysm development secondary to cavitation and drainage into the aorta with control of the infection.6)16 ) the evolutional process was identical irrespective of the species of the infecting microorganism .
such patients should be monitored closely with serial transesophageal echocardiography , which should be repeated every 2 , 4 , and 8 weeks following completion of antimicrobial therapy .
jeang et al.17 ) report a case of aortic root abscess detected with magnetic resonance imaging and echocardiography , and the patient was successfully treated medically .
our patient was treated medically for 4 weeks . for susceptible strains of s. aureus ,
vancomycin was more rapidly bactericidal than penicillin , nafcillin , and cefazolin.18 ) in a rabbit model of s. aureus endocarditis , sterilization of vegetations was more rapid with vancomycin.18 ) combination of vancomycin and gentamicin resulted in more rapid clearing of organisms in animal models,19 ) and in some in vitro models of endocardial vegetations.20 ) in our patient , antimicrobial therapy was changed to vancomycin from nafcillin due to increasing inflammatory signs in the laboratory findings , suggestive of nafcillin resistance .
although the abscess cavity is still present and showed no significant change in size , the patient has no current signs of infection .
infective endocarditis is a serious medical condition , and its management , especially regarding surgical intervention , should be individualized . in summary
, we report a case of staphylococcal infective endocarditis involving tricuspid valve complicated by para - aortic abscess in a 15-year - old man with bicuspid aortic valve .
the patient received 4 weeks of antibiotics therapy and had a good quality of life at 5-month follow - up without surgical treatment .
 paravalvular abscess is a serious complication of infective endocarditis . 
 the aortic valve and its adjacent ring are more susceptible to abscess formation and paravalvular extension than the mitral valve . a 15-years old patient with bicuspid aortic valve presented with staphylococcal tricuspid valve endocarditis complicated by para - aortic abscess that ruptured into the aortic sinus . 
 we report the clinical , laboratory and echocardiographic features and treatment of this patient and conduct a literature review on this subject . 