A Child With a Pericardial Mass and Effusion: A Unique Presentation of a Rare Disease

CASE A 19-month-old female presented to the emergency department following 12 days of persistent fever without an obvious source. In addition to the fever, her mother reported lethargy and a decreased appetite. She otherwise had a healthy medical background, normal gestation and unremarkable birth and was vaccinated according to age. In the emergency department, the patient appeared ill with a fever of 39.1°C. Her vital signs demonstrated tachycardia of 150 beats per minute, tachypnea with a respiratory rate of 40 breaths/min and desaturation to 80% SaO2 in ambient air, with normalization following oxygen support. Blood pressure was normal for age. Physical examination was significant for grunting, decreased breath sounds on the left and muffled heart sounds. A chest radiograph demonstrated hyperdensity of the left hemithorax, with the right border of the heart silhouette shifted right (Fig. 1). An initial diagnosis of pneumonia with effusion was considered. Intravenous antibiotic coverage with cefuroxime was initiated, and the child was transferred to the pediatric intensive care unit (PICU).FIGURE 1.: Chest radiograph demonstrating hyperdense opacity of the left hemithorax.Pulse-oximetry waveform demonstrated an increased variability in association with the breathing pattern, raising suspicion for pulsus paradoxus.1 Bedside chest sonography demonstrated a large pericardial effusion and arterial blood pressure tracing confirmed the pulsus paradoxus pattern, suggesting pericardial effusion with tamponade. Formal echocardiography demonstrated a large pericardial effusion, with a borderline collapse of the right atrium during systole and decreased cardiac output. Surprisingly, a distinct echogenic mass was evident in the pericardial sac, lateral and dorsal to the left ventricle, measuring 6.0 × 2.5 cm in size (Fig. 2). Following intubation and hemodynamic stabilization, an ultrasound-guided pericardiocentesis was performed. A total of 200 mL of serous blood-tinged fluid was removed, resulting in a decrease in pericardial fluid by echocardiography and a dramatic improvement in heart function.FIGURE 2.: Echocardiography of the pericardial mass, clearly delineated in the pericardial fluid, lateral and posterior to the left ventricle. I indicates inferior; Lt, left; LV, left ventricle; Mass, pericardial mass; Rt, right; S, superior.Initial laboratory evaluation included blood gases, which were normal except for mildly elevated lactate (pH of 7.34, lactate of 22 mg/dL); complete blood count, which demonstrated leukocytosis with neutrophilic predominance [white blood cells of 35,800 × 103/mL with 73% polymorphonuclear neutrophils, anemia (hemoglobin of 8.6 g/dL) and thrombocytosis (platelet count of 1054 × 103/mL)]; elevated C- reactive protein (6 mg/dL; normal >0.5 mg/dL); elevated troponin (303 ng/dL; normal <13 ng/dL); and elevated brain natriuretic peptide (18,000 pg/mL; normal <100 pg/mL). Blood biochemistry including renal and hepatic markers were all normal apart from a mildly elevated lactate dehydrogenase (400 U/L; normal 45–200 U/L). Coagulation testing and fibrinogen were normal. In addition, blood culture, ferritin, complement as well as markers for vasculitis and germ cell tumor malignancy were performed. The pericardial fluid contained 4300 × 103 cells/mL of white blood cells, lactate dehydrogenase of 878 IU/L and glucose of 101 mg/dL. The fluid was sent for a broad diagnostic panel, including bacterial cultures, Gram and Ziehl-Neelsen stains, 16S rRNA pan-bacterial polymerase chain reaction (PCR) panel, PCR panel for atypical bacteria and viral PCR for parvovirus, enterovirus, Epstein-Barr virus and cytomegalovirus. Fluid was likewise sent for cytology. Following pericardiocentesis and the patient’s stabilization, a computed tomography (CT) of the chest and abdomen was performed in an attempt to further delineate the pericardial mass. Interestingly, while remnant pericardial effusion was evident, no mass could be identified by CT in the homogeneous fluid-filled sac (Fig. 3). The CT was otherwise normal apart from a discrete and slightly enlarged paratracheal node.FIGURE 3.: Image from the chest CT scan, demonstrating the massive pericardial effusion, without distinguishing the tissue within the fluid.Antibiotic coverage with cefuroxime was continued, and anti-inflammatory treatment was initiated with colchicine and ibuprofen. Over the next 48 hours, the child was monitored in the PICU, ventilated without difficulty and did not require ionotropic support. On the second day of PICU admission, significant fluid re-accumulation was evident by an enlarged cardiac silhouette on chest radiograph and was verified by an echocardiogram, which continued to demonstrate the pericardial mass. As the underlying etiology remained unclear, cardiac surgery was performed via a subxiphoid approach to create a pericardial window for diagnostic tissue sampling. The pericardial mass was easily removed from the pericardial sac (Fig. 4) and sent for additional cultures, 16S rRNA pan-bacterial PCR and for pathologic evaluation for possible malignancy. The child was monitored for an additional 72 hours in the PICU. The fluid did not re-accumulate and drainage diminished. The chest drain was removed on postoperative day 5 without further sequelae.FIGURE 4.: Fibrous inflammatory tissue mass, removed from pericardial space following pericardiotomy.DENOUEMENT Pan-bacterial PCR from the pericardial fluid returned positive for Neisseria meningitidis. Cultures of both blood and pericardial fluid remained negative. Pathology demonstrated fluid rich in neutrophils, a few macrophages and mesothelial cells. The pericardial mass consisted of fibrin with acute inflammatory infiltrate and reactive mesothelium. The pericardium itself demonstrated vascular congestion and an inflammatory infiltrate, all consistent with an inflammatory response without evidence of malignancy. The patient was diagnosed with primary meningococcal pericarditis. Antibiotic coverage was switched to ceftriaxone and continued for a total of 2 weeks. The extended laboratory workup mentioned earlier returned normal for all markers. An immune function evaluation including total immune globulins, subgroups and IgG subclasses, complement, as well as the immune response to rubella vaccination (rubella Ab IgG) were all normal. The child was transferred to the pediatric ward on the eighth day of hospitalization and discharged home 7 days later. Echocardiography at discharge and at subsequent follow-up 1 week later demonstrated normal heart anatomy and function without pericardial effusion. Colchicine therapy was continued on discharge, pending further consultation by the cardiac clinic. Pericardial effusion is a medical condition characterized by the abnormal accumulation of fluid within the pericardial sac surrounding the heart. Common etiologies encompass a broad spectrum of diseases, including infectious, neoplastic, autoimmune, metabolic, traumatic and drug-related culprits. Viral infections are a leading cause, of which enteroviruses (coxsackieviruses, echoviruses), adenovirus, parvovirus B19 and the herpesviruses family are the most common.2 Bacterial pericarditis is a relatively rare event in the antibiotic era. Staphylococcus aureus and Streptococcus pneumoniae are the most reported bacterial etiologies.3Neisseria meningitidis has been described but is rare in comparison. Currently, tuberculosis has been found as a leading bacterial cause, specifically in developing countries where tuberculosis is endemic, as well as among immunosuppressed individuals.4,5 Malignancies associated with pericarditis include primary pericardial mesothelioma, leukemia and lymphoma as well as secondary metastatic involvement including breast and lung carcinoma.2 Meningococcal pericarditis may occur secondary to disseminated meningococcal infection (first reported in 1918), as an isolated primary focus of infection (first reported in 1939) or as a delayed, postinfectious, culture-negative, immune-mediated phenomenon.6–8 Our case would fit the second of the above subclasses: isolated primary pericarditis without systemic meningococcemia. While well documented, this is a rather rare occurrence. French data collected from 2089 cases of bacteriologically confirmed meningococcal disease, occurring between 1999 and 2002, identified only 6 cases of isolated pericarditis (0.3%).9 A comprehensive review of the English literature discovered only 2 detailed reports of primary meningococcal pericarditis in infants.10,11 Dupuis et al reported the findings of a French cohort of 51 children with bacterial pericarditis, collected over a 27-year period from 1963 to 1990. Of these, 7 cases were confirmed to be caused by meningococcus. Three of the seven were identified as primary meningococcal pericarditis, while the remaining 4 were secondary to meningococcal meningitis. Additional details were not provided.12 This child presented with fever and a pericardial mass surrounded by effusion, raising concern for malignancy. Interestingly, the tissue mass, which was highly visible on echocardiography, was not visible on the CT (possibly conceived as the gold standard for chest imaging), causing ambiguity about the underlying etiology. This underlines the variability of different imaging modalities when assessing an unclear differential diagnosis. While pericardiocentesis is often sufficient for the treatment of pericardial effusions including those of meningococcal pericarditis,13 the child we describe experienced re-accumulation of fluid and therefore had to undergo surgery with the creation of a pleuro-pericardial window. While pericardiocentesis could potentially have been repeated with a drain left in the pericardial space, our concern for malignancy directed us toward surgery and the potential benefit of obtaining tissue for diagnosis. Pathologic evaluation demonstrated a tissue that consisted of fibrin, surrounded by inflammatory cells, infiltrate and a reactive mesothelium. These findings were consistent with purulent pericarditis secondary to the meningococcal infection. Constrictive pericarditis, a complication of purulent pericarditis, may occur when fibrin remains in the pericardial sac, and therapeutic intrapericardial fibrinolytics have been suggested as a less invasive alternative to pericardiotomy.14 While fibrinolytics have a potential role in the treatment of purulent pericarditis, no formal guidelines exist on this approach, and the treatment holds the potential risk of secondary, possibly life-threatening hemorrhage.15 Early diagnosis, appropriate antibiotic therapy, surgical drainage when relevant and anti-inflammatory treatment may be associated with a favorable outcome of meningococcal pericarditis.8 Following surgery, 14 days of antibiotic treatment, as well as continued care with colchicine, allowed this child to make a complete recovery. Echocardiographic monitoring in the cardiac clinic has demonstrated good function without re-accumulation of fluid.