Introduction
Pseudoaneurysms are localised arterial dilatations resulting from a breach in the vessel wall, allowing blood to escape and accumulate in adjacent tissues. Reference Song, Yang, Shi and Zhu1,Reference Eysenbach, Reis, Bogart, Shivaram and Koo2 Unlike true aneurysms, they lack the full-thickness involvement of the arterial wall. Reference Sharma, Garisa, Kumaran and Varma3 Infection-related pseudoaneurysms are rare but serious complications in children typically associated with prior cardiac surgery or catheter-related interventions. In children with CHD, especially those who have undergone cardiac repair, pseudoaneurysms may present with nonspecific signs such as persistent fever. Diagnosis can be challenging, as initial investigations including transthoracic echocardiography may fail to detect these lesions, particularly in surgically altered anatomy. In such cases, CT angiography provides critical diagnostic insight. Reference Khouchoua, Belkouchi, Lrhorfi, El Haddad, Allali and Chat4 This report presents a case of a right ventricular outflow tract pseudoaneurysm in a child with repaired tetralogy of Fallot, ultimately attributed to infective endocarditis and undetectable on echocardiography.
Case report
A one-year-old male (weight: 10.1 kg) with a history of repaired tetralogy of Fallot presented with recurrent fever. He had undergone complete tetralogy of Fallot repair at 4 months of age which included transannular patch repair for total correction, augmentation of the main and left pulmonary arteries with autologous pericardial patches, pulmonary valve reconstruction (bileaflet) using 0.1-mm polytetrafluoroethylene, tricuspid valve repair, and patent ductus arteriosus division. The patient initially presented to a referring hospital with fever. After completing a course of empiric antibiotics, his symptoms improved but recurred within 24 hours of discharge. Given the persistent fever and his cardiac history, he was transferred to our centre for further evaluation. Upon admission, the patient was febrile but haemodynamically stable with age-appropriate vital signs. Physical examination revealed a 3/6 systolic murmur and mild hepatomegaly; however, there were no signs of meningeal irritation, respiratory distress, or localised infection. No other infectious focus was detected. Initial laboratory findings showed leukocytosis (WBC: 19.97 × 109/L) with neutrophilia (NEU: 12.33 × 109/L), anaemia (HGB: 9.9 g/dL), and markedly elevated inflammatory markers (CRP 195.3 mg/L, procalcitonin 1.78 ng/mL, ESR 12 mm/hr). Due to the persistent fever, history of CHD, and elevated inflammatory markers, a full sepsis work-up was initiated. Transthoracic echocardiography demonstrated findings consistent with prior complete surgical repair of tetralogy of Fallot using a transannular patch and leaflet augmentation. However, no vegetations or other echocardiographic evidence of endocarditis was observed. Despite the absence of overt echocardiographic findings suggestive of infective endocarditis, the patient was empirically started on cefepime, vancomycin, and amikacin due to ongoing clinical suspicion for culture-negative infective endocarditis. As transthoracic echocardiography did not reveal signs of infective endocarditis, and no alternative infectious focus was identified, cardiac CT angiography was performed to further investigate the cause of persistent fever. The CT angiography report revealed a 16 × 14 mm outpouching adjacent to the right ventricular outflow tract and pulmonary valve, extending toward the left lateral aspect, raising suspicion for a pseudoaneurysm (Figure 1). Blood cultures later confirmed Streptococcus mitis/oralis, consistent with an infectious aetiology for the pseudoaneurysm. Notably, the pseudoaneurysm was not visualised on echocardiography, even upon repeat transthoracic echocardiography following the CT angiography. In view of the radiological and clinical suspicion of an infected pseudoaneurysm, surgery was undertaken on hospital day 20. Intraoperatively, a 1 × 2 cm pseudoaneurysm was identified along the lateral aspect of the right ventricular outflow tract patch. The pulmonary valve showed sequelae of infection, and there were secondary necrotic areas in the adjacent tissues. The polytetrafluoroethylene material appeared delaminated (layer-separated), and a tunnel from the pulmonary valve into the pseudoaneurysm sac was observed. The pseudoaneurysm and the prior polytetrafluoroethylene valve were completely resected, and specimens were sent for culture. The right ventricular outflow tract was then reconstructed with bovine pericardium. Postoperative cardiac output was normal. The patient had an uneventful postoperative course, including extubation within the first 24 hours, 48 hours of cardiac ICU monitoring before transfer to the ward, and remained afebrile and clinically stable during follow-up. Microscopy of the resected material demonstrated leukocyte-rich inflammatory exudate; however, intraoperative cultures showed no growth, likely reflecting the prior 20-day course of antibiotic therapy. The patient was discharged in good condition following completion of a 6-week course of antibiotic therapy and continues to be followed up in an outpatient paediatric cardiology clinic.
Cardiac CT angiography showing a 16 × 14 mm pseudoaneurysm (arrow) adjacent to the right ventricular outflow tract and pulmonary valve, extending to the left lateral side. The lesion was not detected on transthoracic echocardiography. Shown in multiple orthogonal planes: axial ( a ), coronal ( b ), sagittal ( c ), and oblique sagittal ( d ). PA = pulmonary artery.
Figure 1. Long description
Panel A: A cross-sectional CT image in the axial plane showing a pseudoaneurysm (indicated by an arrow) adjacent to the right ventricular outflow tract and pulmonary valve. The pulmonary artery is labeled as PA. Panel B: A cross-sectional CT image in the coronal plane showing the pseudoaneurysm (indicated by arrows) extending to the left lateral side. Panel C: A cross-sectional CT image in the sagittal plane showing the pseudoaneurysm (indicated by arrows) adjacent to the right ventricular outflow tract. Panel D: A cross-sectional CT image in the oblique sagittal plane showing the pseudoaneurysm (indicated by arrows) adjacent to the right ventricular outflow tract and pulmonary valve.
Discussion
Infective endocarditis remains an uncommon but serious condition in the paediatric population. Reference Gupta, Sakhuja, McGrath and Asmar5 The presence of CHD is the most significant risk factor, especially in the first six months following surgical repair. Reference Rushani, Kaufman and Ionescu-Ittu6 In this case, a one-year-old patient with repaired tetralogy of Fallot developed recurrent fever. Blood cultures revealed Streptococcus mitis/oralis, members of the viridans streptococci group known for their role in subacute bacterial endocarditis, particularly in patients with underlying CHD. Viridans streptococci account for nearly one-third of paediatric infective endocarditis cases with underlying CHD. Reference Gupta, Sakhuja, McGrath and Asmar5 These organisms can adhere to damaged endothelium or prosthetic material, leading to destructive infection. The presence of this pathogen, in the context of the patient’s cardiac history, strongly supported an infectious origin. Although echocardiography revealed no vegetations, persistent fever and elevated inflammatory markers necessitated further investigation. CT angiography subsequently identified a pseudoaneurysm of the right ventricular outflow tract, later confirmed intraoperatively as an infected pseudoaneurysm with delaminated polytetrafluoroethylene, secondary necrosis in surrounding tissues, and a tunnel from the pulmonary valve into the pseudoaneurysm sac. Notably, the pseudoaneurysm remained undetectable on transthoracic echocardiography, emphasising the modality’s limitations in evaluating certain post-surgical complications. Furthermore, the constellation of findings in this patient aligns with the modified Duke criteria. Positive blood cultures for Streptococcus mitis/oralis and cardiac CT evidence of a right ventricular outflow tract pseudoaneurysm fulfil two major criteria. Minor criteria included predisposing CHD and fever. Taken together, these findings fulfil the clinical criteria for definite infective endocarditis within the modified Duke framework. Intraoperative findings—infected pseudoaneurysm with delaminated polytetrafluoroethylene, secondary necrosis in surrounding tissues, and a tunnel from the pulmonary valve into the pseudoaneurysm sac—were also observed, and microscopy of the resected material demonstrated leukocyte-rich inflammatory exudate, also supporting the diagnosis. Reference Fowler, Durack and Selton-Suty7 This case illustrates the importance of CT angiography in detecting otherwise occult lesions in paediatric patients with CHD.
Conclusion
Computed tomography angiography can be a crucial diagnostic tool when transthoracic echocardiography fails to reveal the source of infection in paediatric patients with CHD and suspected infective endocarditis. Early imaging and prompt surgical management may prevent serious complications and improve clinical outcomes.
Financial support
This research received no specific grant from any funding agency, commercial or not-for-profit sectors.
Competing interests
No potential conflicts of interest relevant to this article were reported.
Consent statement
Written informed consent was obtained from the patient’s legal guardians for the publication of this case report and any accompanying images.
