Pulmonary endocarditis and ventricular septal defect: an incidental diagnosis
Infective endocarditis of the pulmonary valve (PVIE) is a rare pathology, particularly in patients without classic risk factors. Early diagnosis is crucial to limit high morbidity and mortality. This case report documents the management of a 33-year-old male, with type 2 diabetes, presenting with PVIE complicated by a mycotic aneurysm of the pulmonary artery and a splenic infarction.
The objective of this clinical presentation is to detail the diagnostic process leading to the incidental discovery of a 19 mm perimembranous ventricular septal defect (VSD), which served as a nidus for infection. The report highlights the importance of multimodal imaging — combining transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE) and CT scan — to identify the embolic and structural complications associated with this right-sided valvular involvement.
Rather than testing an experimental hypothesis, this work describes the favorable clinical evolution under targeted intravenous antibiotic therapy in the face of a Streptococcus pharyngis infection. It highlights the necessity for the practitioner to systematically integrate the search for underlying congenital anomalies when managing right-sided endocarditis in adults.
Methodology and Case Presentation
This case report documents the diagnostic and therapeutic management of a 33-year-old patient with type 2 diabetes (HbA1c 6.7%), presenting with infectious symptoms evolving over 20 days (asthenia, fever, arthralgia). The diagnostic protocol was based on a multimodal approach combining clinical examination, advanced cardiovascular imaging, and microbiological analyses.
- Cardiovascular Imaging: Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were performed to evaluate valvular and septal structures. Measured parameters included vegetation size (11.8 × 7 mm), ventricular septal defect diameter (VSD of 19 mm), left-to-right shunt gradient (52 mmHg), and pulmonary transvalvular velocity (4.9 m/s, gradient of 98 mmHg).
- Thoraco-Abdominal Imaging: A CT scan was used to screen for embolic complications, identifying a mycotic aneurysm of the superior segmental artery of the right upper lobe and a splenic infarction.
- Microbiological and Biological Analyses: The etiological diagnosis was established by three positive blood cultures identifying Streptococcus pharyngis. The initial biological assessment measured anemia (Hb 7.5 g/dL), leukocytosis (25,580/µL with 21,794/µL neutrophils), thrombocytosis (745,000/µL) and a marked inflammatory syndrome (CRP 139.9 mg/L).
- Therapeutic Protocol: Management consisted of prolonged intravenous antibiotic therapy, aimed at clinical resolution and normalization of biological parameters.
Clinical profile and biological markers
The 33-year-old patient presented with infectious symptoms evolving over 20 days, marked by sinus tachycardia at 145 bpm and a right holosystolic murmur upon auscultation. Physical examination revealed vascular petechial purpura on the lower limbs.
The initial biological assessment revealed a severe systemic inflammatory response, anemia, and impaired renal function:
| Parameter | Measured value | Reference value |
|---|---|---|
| Hemoglobin (Hb) | 7.5 g/dL | 13-17 g/dL |
| Leukocytes | 25,580/µL | 4,000-10,000/µL |
| Neutrophils | 21,794/µL | 2,000-7,500/µL |
| Plaquettes | 745,000/µL | 150,000-400,000/µL |
| C-Reactive Protein (CRP) | 139.9 mg/L | < 5 mg/L |
| Urea | 1.04 g/L | 0.15-0.45 g/L |
| Creatinine | 35.85 mg/L | 6-12 mg/L |
Echocardiography and structural imaging
Transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE) identified a 19 mm perimembranous ventricular septal defect (VSD) with a left-to-right shunt (52 mmHg gradient). Pulmonary valve involvement is characterised by:
- The presence of multiple vegetations, the largest measuring 11.8 × 7 mm.
- Severe pulmonary regurgitation.
- A functional stenosis with a maximum velocity of 4.9 m/s and a peak gradient of 98 mmHg.
Thoraco-abdominal CT imaging completed the lesion assessment, revealing a mycotic aneurysm of the superior segmental artery of the right upper lobe as well as a splenic infarction.
Microbiology
Microbiological investigations were conclusive. Three blood cultures returned positive for Streptococcus pharyngis, confirming the bacterial etiology of this pulmonary valve infective endocarditis (PVIE) according to the modified Duke criteria.
Shunt hemodynamics and valvular vulnerability
This case illustrates how a perimembranous ventricular septal defect (VSD) radically alters the infectious risk profile. The left-to-right shunt generates endocardial trauma via a "jet effect" on the pulmonary valve, creating a favorable environment for colonization by Streptococcus pharyngis. This dynamic explains the unusual localization of right-sided endocarditis in an adult patient without classic risk factors, such as intravenous drug use.
Diagnostic complexity and systemic complications
The clinical presentation combining asthenia, fever, and vascular purpura highlights the importance of early multimodal imaging. Transthoracic and transesophageal echocardiography were decisive in quantifying functional stenosis (velocity of 4.9 m/s) and identifying vegetations reaching 11.8 x 7 mm. The concomitant discovery of a splenic infarction and a pulmonary mycotic aneurysm demonstrates the severity of septic emboli and the necessity for extensive CT surveillance as soon as the diagnosis is established.
Clinical limits and findings
The main challenge reported here lies in the incidental diagnosis of the underlying VSD at the age of 33. Although intravenous antibiotic therapy led to a marked clinical improvement and normalization of biological parameters (leukocytosis and C-reactive protein), the management of structural lung damage in adults remains complex. This case reminds clinicians that a holosystolic murmur, even in a stable patient, requires a rigorous evaluation to exclude an unrecognized congenital heart disease, a major risk factor for right-sided infective endocarditis.
Summary of results
This case reports pulmonary valve endocarditis (PVE) in a 33-year-old male, incidentally revealing a 19 mm perimembranous ventricular septal defect (VSD) (gradient 52 mmHg). The Streptococcus pharyngis infection caused severe embolic complications, including a splenic infarction and a mycotic aneurysm of the pulmonary artery with functional stenosis (peak gradient of 98 mmHg).
In concrete terms, for the practitioner:
- Systematic screening: In the presence of any right-sided endocarditis, actively look for an underlying congenital heart disease (such as VSD), even in an adult with no known cardiac history.
- Embolic vigilance: A Streptococcus infection requires screening for pulmonary septic emboli (aneurysms) and systemic septic emboli (splenic infarction) using CT imaging as soon as the diagnosis is suspected.
- Contribution of TEE: Transoesophageal echocardiography is essential for mapping vegetations and precisely quantifying transvalvular gradients, which are often underestimated during transthoracic examination.
Source
- Original title: Pulmonary Valve Endocarditis With Mycotic Pulmonary Aneurysm Revealing a Previously Undiagnosed Perimembranous Ventricular Septal Defect in an Adult
- Authors: Mehdi Berrajaa, Hala Jaouhari, Amine El Houari, Wassim Beladel, Khalil Abderrahmane Elbaz, Mohamed El Minaoui
- Publication: Cureus - 2025-09-10
- DOI: https://doi.org/10.7759/cureus.92008
Information intended for healthcare professionals. This content may contain errors or truncated summaries. We recommend always verifying with the original source article. Delynov disclaims any responsibility regarding the use of this information. This document is not intended for patients or the general public.