Bronchomediastinal fistula presenting as purulent pericarditis in a healthy 32-year-old man

Abstract

Acute purulent pericarditis is rarely caused by anaerobic bacteria and it is almost always a complication of another disease process. Esophagomediastinal fistula, odontogenic, or pleuropulmonary infections have been reported to be the primary source of purulent pericarditis. If not diagnosed and treated promptly, purulent pericarditis is usually a fatal disease. We describe a case of bronchomediastinal fistula as sequels from a necrotizing parenchymal infection, leading on to secondary mediastinitis and pleuropericardial involvement in an immunocompetent patient.

<Learning objective:Eikenella corrodens is an important pathogen associated with a spectrum of intrathoracic suppurative infections. Purulent pericarditis can be fatal if not recognized early enough. Physicians should be aware of such a presentation.>

Introduction

Acute purulent pericarditis is rarely caused by anaerobic bacteria and it is almost always a complication of another disease process. Esophagomediastinal fistula, odontogenic, or pleuropulmonary infections have been reported to be the primary source of purulent pericarditis. If not diagnosed and treated promptly purulent pericarditis is usually a fatal disease.

Case report

A previously healthy 32-year-old Hispanic man presented with acute onset retrosternal chest pain associated with subjective fever, dry cough, and dyspnea on exertion. Physical examination was remarkable for pericardial friction rub. Laboratory studies showed leukocytosis with left shift and elevated erythrocyte sedimentation rate. The electrocardiogram revealed sinus tachycardia with diffuse ST segment elevation, and PR segment depression consistent with the diagnosis of acute pericarditis. The patient was treated with ibuprofen. On day 2 of admission, the patient's clinical condition deteriorated and became more dyspneic and tachypneic. Transthoracic echocardiography (TTE) showed moderate pericardial effusion with no evidence of tamponade (Fig. 1). Computed tomography scan of the chest revealed left bronchomediastinal fistula with mediastinal adenopathy along with moderate pericardial and bilateral pleural effusions (Fig. 2). A rigid bronchoscopy confirmed the presence of 1 cm in size left bronchomediastinal fistula. Thoracocentesis was performed and 130 ml of pus was drained. Both blood culture and pleural fluid culture grew Eikenella corrodens. The patient was started on intravenous ampicillin after sensitivity and susceptibility testing. There was no obvious cause for the bronchomediastinal fistula, since the patient never had symptoms of respiratory or oropharyngeal disease or previous trauma. Barium swallow study and esophagogastroduodenoscopy were normal. The patient underwent operative drainage of the pericardial sac, debridement and decortications of the left lung, and placement of silicone stent at the left main bronchus (Fig. 3). He completed four weeks of intravenous ampicillin. The patient's clinical condition continues to improve and he was discharged home three weeks after the surgery. The bronchial stent was removed six weeks later during follow-up visit.

Fig. 1.

Transthoracic echocardiogram: Apical four-chamber view reveals circumferential moderate pericardial effusion 1.5 cm. RV, right ventricle; LV, left ventricle; RA, right atrium; LA, left atrium; PE, pericardial effusion.

Fig. 2.

(A) Axial computed tomography of the chest demonstrated left main bronchomediastinal fistula (arrowhead) with loculated left sided pleural effusion (asterisk). (B) Coronal computed tomography of the chest showed mediastinal air pocket and left main fistula tract (yellow arrow).

Fig. 3.

Bronchoscopy view demonstrates silicone stent at the left main bronchus.

Discussion

Purulent pericarditis is an acute inflammation of the pericardium characterized by pus formation. The disease appears as an acute fulminant infectious illness. It became a rare clinical entity in the era of antibiotics. Predisposing factors include immunosuppression, alcohol use, chronic illness, cardiac surgery, and chest trauma.

Common pathogens are streptococci, staphylococci, Haemophilus influenzae, Gram-negative rods, and increasingly anaerobic bacteria [1]. E. corrodens is a fastidious, facultatively anerobic, Gram-negative bacillus which belongs to the HACEK (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella spp.) group [2]. It is a common resident flora of the gastrointestinal tract especially the oral cavity and genitourinary tract. Although traditionally associated with periodontal infections and human bite wounds, it is being increasingly implicated in many suppurative infections of the head and neck region as well as pleuro-pericardial space and mediastinum, mostly as a part of mixed flora 3, 4. Here we describe a case of purulent pericarditis with accompanying empyema occurring as a complication of a bronchomediastinal fistula in an immunocompetent host.

Our case underscores the fact that pleuro-pulmonary infection is an important manifestation of Eikenella infection although the pericardial involvement was the presenting symptom in our case and also that it can be the sole organism involved, which was further substantiated by the isolation of the same in blood culture as well. One of the peculiarities of our case was that there was no apparent predisposing factor which was contrary to the observation made in the reported case series 2, 3, 4, 5, 6.

It is conceivable that the pericardial involvement in our case was secondary to contiguous spread of infection from adjoining pleural and mediastinal structures and there is no reported case of isolated pericardial involvement with Eikenella infection in the literature. Almost all cases of Eikenella intrathoracic infections, where pericarditis has been reported either as a presenting symptom or an asymptomatic association, have concomitant pleuro-pulmonary and mediastinal infections. Our patient had a bronchomediastinal fistula which could have ensued from a necrotizing parenchymal infection to begin with, leading on to secondary mediastinitis and pleuro-pericardial involvement.

Conclusion

E. corrodens is an important pathogen associated with a spectrum of intrathoracic suppurative infections in isolation and also as a part of mixed flora, in both immunocompetent and immunosuppressed individuals. Its role was probably underrecognized due to the fastidious growth requirement of the organism and prior use of antibiotics.

Funding source

None.

Disclosure and conflict of interest statement for all authors

None.