Quadri-valvular endocarditis caused by Streptococcus mutans


Although multivalvular endocarditis is common, infection of all four cardiac valves is exceedingly rare. We describe a case of Streptococcus mutans quadri-valvular endocarditis diagnosed by transesophageal echocardiography (TEE).

A 48-year-old man with a history of alcoholic cirrhosis was admitted to the hospital with anasarca and jaundice. Three months prior to admission, he first experienced lower back pain which progressively worsened. Several days prior to presentation, he noticed dyspnea at rest and swelling of the lower extremities. He became jaundiced 2 days prior to admission, but had no abdominal pain, fever or chills. He had no history of trauma, recent dental work, or a previous murmur.

On admission, he was icteric, but afebrile. He had a blood pressure of 92/50 mmHg, and a pulse of 90 beats/min. There was no jugular venous distension and the lungs were clear. Cardiac examination revealed a fourth heart sound without a murmur or rub. The abdomen was non-tender without shifting dullness, and the liver was normal in span. Splenomegaly was present. There was 4+ pitting edema of the lower extremities with petechiae on the dorsum of both feet. Mild asterixis was present.

Initial laboratory tests included a white blood cell count of 24 000/mm3 (76% neutrophils and 18% bands), a hematocrit of 39% with platelet count of 56 000/mm3, and an erythrocyte sedimentation rate (ESR) of 33 mm/h. Abnormal serum findings were: sodium 118 mEq/dL, chloride 87 mg/dL, bilirubin 6.8 g/dL, and albumin 1.4 g/dL. The prothrombin time was 17.9s. The chest X-ray was normal and the electrocardiogram showed normal sinus rhythm with non-specific ST–T-wave changes. Blood cultures were obtained. The patient's working diagnosis was subacute bacterial endocarditis, and the patient was started on penicillin 4 MU (IV) 4-hourly and gentamicin 240 mg (IV) 24-hourly. S. mutans was isolated in two cultures from each of two blood specimens.

On the third hospital day, a new grade II/IV systolic murmur was heard at the left sternal border which did not change with respiration. A transthoracic echocardiogram revealed echogenic mobile masses on the atrial aspect of the mitral valve and ventricular aspect of the aortic valve. TEE was performed and demonstrated discrete vegetations on all four cardiac valves (Figure 1). His back pain persisted and a magnetic resonance image (MRI) was obtained which revealed L4–L5 vertebral osteomyelitis. The patient was treated with a 6-week course of penicillin 4 MU (IV) 4-hourly and gentamicin 240 mg (IV) 24-hourly. Subsequently he developed intractable congestive heart failure related to severe aortic insufficiency, and he died on the 63rd hospital day.

Figure 1.

Transesophageal echocardiographic images showing a small echodensity on the left atrial side of the mitral valve (left upper panel), a moderate-size echodensity on the ventricular aspect of the aortic valve (right upper panel), a large echodensity on the right atrial side of the tricuspid valve (left lower panel), and a small echodensity on the right ventricular side of the pulmonary valve (right lower panel). These features are indicated by arrows.

This report describes the first case of S. mutans endocarditis affecting all four cardiac valves diagnosed by TEE. S. mutans is a known cause of subacute bacterial endocarditis accounting for 1.7% to 14% of cases of streptococcal endocarditis [1]. Although multivalvular endocarditis is not uncommon, a review of the literature has revealed only five previous cases of quadri-valvular endocarditis [2–6]. The clinical features of these cases are summarized in Table 1. With one exception, factors predisposing to endocarditis were present in all patients; intravenous drug use and alcoholism were common. The causative bacteria included Pseudomonas aeruginosa, Serratia marcescens, Streptococcus bovis, Corynebacterium CDC group II, and a Streptococcus viridans (not speciated). Our patient also had vertebral osteomyelitis, which has been described previously by Spadafora et al. [2]. In our case, vegetations were found on the mitral and aortic valves on a transthoracic echocardiogram (TTE), but the smaller vegetations on the two other valves were not apparent. In two of the previously reported cases, vegetations were demonstrated on all four valves by TTE. All previous patients died and the pathology was confirmed at autopsy. Our patient died of intractable congestive heart failure after having received a 6-week course of appropriate antibiotic therapy [3–7].

Table 1.  Quadri-valvular endocarditis: review of the literature
Patient no.SexAgePredisposing factorsOrganismAntemortem valve involvement by TTEComplications/OutcomeReference
  1. aVegetations on all four valves by TEE.

  2. AV=aortic valve; MV=mitral valve; TV=tricuspid valve; NA=not applicable.

1Male24IV drug usePseudomonas aeruginosaAllDied3
2Female56Renal failurePseudomonas aeruginosaNADied4
    Serratia marcescens   
   IV drug useCDC group IITV  
4Male58AlcoholismStreptococcus bovisAVDied6
5Female78NoneStreptococcus viridansAllDied7
6Male48AlcoholismStreptococcus mutansAVaVertebral osteo/DiedPresent case