Actinomycotic Endocarditis of the Eustachian Valve: A Rare Case and a Review of the Literature

Abstract

Eustachian valve endocarditis caused by Actinomyces species is extremely rare. A literature review revealed only one reported case—caused by Actinomyces israelii in an intravenous drug abuser.

Our patient, a 30-year-old woman who at first appeared to be in good health, presented with fever, a large mobile mass on the eustachian valve, and extensive intra-abdominal and pelvic masses that looked malignant. Histopathologic examination of tissue found in association with an intrauterine contraceptive device revealed filamentous, branching microorganisms consistent with Actinomyces turicensis. This patient was treated successfully with antibiotic agents.

In addition to presenting a new case of a rare condition, we discuss cardiac actinomycotic infections in general and eustachian valve endocarditis in particular: its predisposing factors, clinical course, sequelae, and our approaches to its management.

Actinomyces species are anaerobic-to-microaerophilic bacteria that survive as normal flora within the mouth, bronchi, gastrointestinal tract, and female genital tract. These organisms are rarely associated with chronic pyogenic or granulomatous infections in the general population.¹ Actinomycotic infections are generally limited to the cervicofacial (50%), pulmonary (15%), and intra-abdominal (20%) areas. Cardiac involvement is relatively rare; most infections occur by contiguous metastasis to the pericardium and very rarely by hematogenous metastasis to the cardiac valves.² Infection of the eustachian valve (EV) by Actinomyces species is extremely rare, having (to our knowledge) been reported only once before.³ We report a case of EV endocarditis caused by Actinomyces turicensis in an apparently healthy young woman, possibly transmitted by an intrauterine contraceptive device (IUD). In our accompanying review of the relevant literature, we discuss the predisposing factors, the clinical course, and the treatment of various actinomycotic and EV endocarditis.

Case Report

In September 2011, a 30-year-old woman was admitted with right upper quadrant pain and swelling of one week's duration. Her medical history included no recent dental work, no human immunodeficiency viral infection, and no history of intravenous drug use. She had undergone a cesarean section 2 years before presentation, after which an IUD had been placed. Physical examination at admission revealed a firm mass, slightly painful to the touch, in the right upper quadrant. Laboratory results showed marked leukocytosis. A transvaginal ultrasonogram and a computed tomogram revealed multiple large masses in the ovaries, pelvis, and liver that were suspect for extensive metastatic disease, presumably ovarian in origin. Histopathologic studies of tubo-ovarian (Fig. 1A) and liver (Fig. 1B) biopsy samples failed to reveal any malignant cells. Instead, they showed microabscesses with branching filamentous microorganisms consistent with Actinomyces species. The patient subsequently underwent an exploratory laparotomy, which revealed multiple pockets of pus with extensive inflammatory changes and fibrinous adhesions. Evacuation of pus was performed, along with total abdominal hysterectomy, right salpingo-oophorectomy, appendectomy, and lysis of adhesions. Cultures of fluid from both the abdominal cavity and the IUD grew A. turicensis. Multiple sets of blood cultures performed on the day of admission and during the patient's hospital course failed to reveal any growth of microorganisms.

Fig. 1.

A) Photomicrograph of tubo-ovarian section shows colonies of Actinomyces with a branching filamentous appearance (H & E, orig. ×200). B) Photomicrograph of liver biopsy specimen shows branching filamentous bacteria, surrounded by liver parenchyma (Grocott-Gomori methenamine-silver stain, orig. ×400). C) Computed tomogram performed with intravenous and oral contrast medium reveals a large abscess of the liver (arrow) eroding into the anterior abdominal wall.

In view of the extensive actinomycotic infection and consequent risk of abdominal-wall fistula formation, we started her on broad-spectrum antibiotics, including penicillin G, ceftriaxone, and metronidazole. Despite the abdominal surgery and antibiotic therapy, the patient continued to be febrile and hypotensive over the next few days. A 2nd computed tomogram of the abdomen showed a right hepatic lobe abscess, which eroded the anterior abdominal wall and extended into the subcutaneous fat of the epigastrium (Fig. 1C). A transthoracic echocardiogram (TTE), performed for the evaluation of any cardiac cause of hypotension, showed a 2.7 × 2-cm mobile and multilobulated echogenic mass attached to a congenitally complete EV in the right atrium. This mass was consistent with a large EV vegetation, probably the product of hematogenous actinomycotic seeding from the liver abscess (Figs. 2A–B). The tricuspid valve was free of any vegetation and displayed minimal tricuspid regurgitation. The patient underwent surgical drainage of the liver abscess, and the course of antimicrobial therapy was continued.

Fig. 2.

Transthoracic echocardiograms. A) The apical 4-chamber view reveals a mobile, multilobulated vegetation (arrow) attached to the mid portion of a complete eustachian valve. B) The parasternal short-axis view reveals a mobile vegetation (arrow) attached to the eustachian valve. C) After 3 weeks of antibiotic therapy, the apical 4-chamber view reveals complete resolution of the vegetation.

Postoperatively, she showed gradual clinical improvement, along with resolution of her fever and leukocytosis. In order to reevaluate the extent of cardiac involvement, we repeated TTE on day 20 after the patient's initial presentation, and this showed near-complete resolution of the vegetation (Fig. 2C). After a month-long hospital course on the previously mentioned antibiotic agents, the patient was discharged from the hospital on penicillin G and imipenem. She received these 2 agents for an additional 30 days, which concluded 8 weeks of therapy in total. During the next 16 months of follow-up at our infectious diseases clinic, complete clinical and radiographic recovery was documented.

Discussion

In the fetal circulation, the eustachian valve directs oxygenated blood from the inferior vena cava through the foramen ovale, and into the left atrium. In adults, it is usually a rudimentary and benign nonfunctional structure. Eustachian valve endocarditis, first described in 1986 by Edwards and colleagues⁴ in a patient who died of staphylococcal septicemia and lung abscesses, is distinctly rare. Since 1986, only 29 additional cases of EV endocarditis have been reported (Table I).^4–24 The usual predisposing factor for EV endocarditis is intravenous drug use. Other causes include indwelling catheters, rheumatic heart disease, pacemaker wires, and immunologic compromise (such as that caused by chronic alcoholism or the human immunodeficiency virus).^12,15,18

TABLE I.

Reports of Eustachian Valve Endocarditis

In the presence of intravenous drug use, the usual causative pathogen is Staphylococcus aureus.¹⁴ Other organisms, not specifically associated with intravenous drug use, include Staphylococcus hominis,⁶ Enterobacter cloacae,¹⁰ Escherichia coli,¹⁴ Proteus vulgaris,¹⁴ Streptococcus viridans,¹² Klebsiella pneumonia,^16,19 and Actinomyces israelii.³ Pericardial actinomycotic infections are known to occur by contiguous spread from adjacent thoracic structures. In patients with underlying rheumatic heart disease or a history of intravenous drug use,^25,26 Actinomyces species are also a reported cause of aortic, mitral, and (rarely) tricuspid valve endocarditis (Table II^27–45). Kennedy and colleagues³ reported a case of EV endocarditis caused by A. israelii in an intravenous drug user who had a history of treatment for staphylococcal tricuspid valve endocarditis. Because of persistent fever, the patient underwent surgical excision of the vegetation.

TABLE II.

Reports of Actinomycotic Endocarditis

For the diagnosis of EV endocarditis, TTE is usually the test of choice for initial imaging. Although transesophageal echocardiography might yield relatively better images of the EV, its use as an initial diagnostic tool in all patients suspected to have EV endocarditis remains controversial.^46,47 We recommend a transesophageal echocardiogram in patients with a high clinical suspicion of endocarditis, in whom a TTE fails to accurately define cardiac structures, including the EV.

In most cases of EV endocarditis reported to date, medical therapy with appropriate antibiotics has shown resolution of the vegetations. Surgery is reserved for nonresponders or for patients with evidence of septic emboli or symptoms of congestive heart failure. Penicillin G remains the mainstay of treatment for actinomycosis. Alternative regimens for patients with allergy to penicillin include 3rd-generation cephalosporin (ceftriaxone), clindamycin, erythromycin, and doxycycline.⁴⁸

Our patient with EV endocarditis was a previously healthy young woman who acquired extensive A. turicensis infection of her intra-abdominal and pelvic structures mimicking malignancy, although its most likely cause was an infected IUD. Despite the absence of a cardiac histologic diagnosis in this case, several factors support the diagnosis of actinomycotic EV endocarditis: a high degree of suspicion for cardiac involvement of Actinomyces, a lack of evidence to support an alternative diagnosis, and successful resolution of the vegetation with antibiotic treatment. We conclude that endocarditis, particularly of the eustachian valve, should be suspected in patients who have such extensive actinomycotic infection. Prompt diagnosis and appropriate intervention is recommended to reduce the risk of such sequelae as septic emboli, congestive heart failure, and death.