Infective endocarditis in adult congenital heart disease: A case report

Akbar Ali1, S .Aravindakumar2

Cardiology registrar, Kauvery Heart City, Trichy

Chief consultant interventional cardiologist, Kauvery Heart City, Trichy

Background

Infective endocarditis (IE) is a severe and potentially life-threatening infectious & inflammatory condition and has been continuously evolving over the last 3-4 decades as highlighted by many studies from the developed world. It is characterized by the inflammation of the endocardium, typically involving the heart valves. It remains a significant clinical challenge due to its potential for severe complications associated with substantial morbidity and mortality including valvular destruction, systemic embolization, and heart failure. It is commonly associated with structural abnormalities such as valvular defects, prosthetic valves, or intracardiac devices. Although the majority of cases involve the left side of the heart, IE can also affect the right heart chambers, particularly in the presence of congenital heart disease, intravenous drug abuse and instrumentation of the right heart are predisposing factors for right-sided IE.

Case Presentation

A 57 years old female, known to have congenital acyanotic heart disease – subaortic perimembranous ventricular septal defect (VSD), systemic hypertension and depression disorder, presented to our hospital with history of intermittent high grade fever, along with polyarthralgia, malaise and loss of appetite for more than 6 months duration for which the patient had been admitted and treated several times at various hospitals with partial remission of symptoms.

During a previous admission at a local hospital, she was diagnosed to have right third toe wet gangrene. Arterial Doppler study of the right lower limb revealed a biphasic wave pattern in right anterior, posterior and dorsalis pedis arteries with no compromised flow velocity and vessel lumen size. Subsequently the patient underwent ray amputation of the right third toe for wet gangrene with no apparent vascular etiology and was discharged from the local hospital.

However the patient’s symptoms did not resolve with antimicrobial therapy.

Prior to the patient’s illness, she had been referred for ulcerative forefoot infection with foul smelling and purulent discharge for which the patient did not seek proper medical attention.

On Examination

Physical examination at our center upon presentation revealed normal blood pressure of 110/60 mmHg, sinus tachycardia with heart rate of 98 beats per minute, respiratory rate of 18 breaths per minute and axillary temperature of 101.5°F.

Cardiac examination revealed a loud pan systolic murmur, heard at the lower left sternal border. The lung examination was within normal limits.

Physical examination over right forefoot showed noted an ulcerative and infected wound with purulent discharge.  No other vascular or immunologic phenomena of IE were detected.

Lab Investigations

Laboratory investigation revealed anemia with hemoglobin level of 10.5 g/dL, thrombocytopenia with platelet count of 36000 cells/cumm., normal total white count of 8800 cells/cumm., elevated ESR and CRP. The liver and kidney function tests were within normal limits.

In view of the prolonged fever with underlying congenital heart disease – VSD, this patient was suspected to have infective endocarditis, so transesophageal echocardiography (TEE) was done which revealed 8×5mm vegetative growth seen in the RV side of the subaortic perimembranous ventricular septal defect. Evaluation showed all the four cardiac chambers to be normal in size with good LV systolic function (ejection fraction 60%) and no regional motion wall abnormalities.

Four sets of blood cultures from 3 different sites grew streptococcus gordonii.

Management

  • Patient was diagnosed with definite infective endocarditis based on modified Duke Criteria. She was treated with culture sensitive broad spectrum intravenous antimicrobial agent, ceftriaxone, with marked improvement in her symptoms and, well being. Platelet count rose to 1,00,000 cells/cumm after treatment with culture sensitive antimicrobial therapy.
  • She remained afebrile throughout the admission after initiation of antibiotics and was safely discharged with intravenous antibiotics to be administered at a local hospital for 6 weeks duration with regular follow-up at our center.

TEE images of the patient

 

(3)

Impression

First image of TEE shows the arrow pointing to vegetation formation at the RV side of VSD. Second and third image shows a left to right shunt of doppler flow across VSD.

Discussion

Infective endocarditis affects 14.5 cases per 100000 patient-years in India, which is very high compared to the western incidence which is around 1.7–6.2 cases per 100000 patient-years. Among congenital heart disease, ventricular septal defect (VSD) is the most frequent anomaly in right-sided IE. The incidence of IE among VSD was 0.2–2%. Uncorrected VSD is a predisposing factor for IE, especially right-sided IE. IE in the setting of a subaortic per membranous VSD is a rare but potentially life-threatening condition.

In our case, the patient fulfilled modified Duke Criteria with the finding of two major and three minor criteria:

  • Intracardiac vegetation,
  • Positive blood cultures,
  • High grade fever,
  • Predisposing cardiac condition,
  • Vascular phenomena – arterial emboli (third right toe).

Our patient had vegetation formation in the VSD, which was where the site of turbulent flow in the left-to-right shunt occurred. This perpetual turbulent flow was damaging for endothelial cells, which could have led to vegetation formation.

The right third toe wet gangrene was most probably due to septic embolism which results from infective endocarditis; thrombocytopenia also results from sepsis due to IE.

Around 80–90% of IE cases result from staphylococcal, streptococcal, and enterococcal infection. Staphylococcus aureus is the most frequent microorganism in right-sided IE among intravenous drug users, whereas Streptococcus viridans is the predominant microorganism in nondrug users. Streptococcus gordonii, a Gram-positive bacterium, is a commensal bacterium that is commonly found in the skin, oral cavity, and intestine. It is also known as an opportunistic pathogen that can cause local or systemic diseases, such as apical periodontitis and infective endocarditis.

The source of infection in our case could be from the infected forefoot wound for which no proper medical attention sought. In recent years, S. gordonii have been increasingly found as relevant microbial pathogens in abscesses causing bloodstream infection which play a pathogenic role in disseminated infections.

In IE, management usually focused on culture sensitive antimicrobial therapy and eliminating the source of infection.

Surgical intervention for right-sided IE may be performed by considering several conditions such as heart failure, persistent infection despite appropriate antimicrobial therapy, valvular involvement, abscess formation, hemodynamic instability, right heart failure due to severe tricuspid regurgitation with poor response to medication, tricuspid valve vegetation of >20 mm and recurrent pulmonary embolism.

Most reports show a high success rate of antibiotics treatment for right-sided IE. The need for surgical intervention is <30%. However, our case showed good response with appropriate antimicrobial therapy. Therefore, she was continued with culture sensitive broad spectrum intravenous antibiotics and planned for VSD closure after completion of antibiotics to prevent the recurrence and repeat TEE to ensure resolution of vegetation.

Conclusion

This case underscores the importance of considering infective endocarditis in the differential diagnosis of febrile patients with congenital heart disease, particularly those with a history of ventricular septal defects. A high index of suspicion, prompt diagnosis, and timely intervention are crucial for improving outcomes in this challenging clinical scenario because it has the potential for fatal outcome. Continued research and collaborative efforts are needed to further elucidate the optimal management strategies for IE complicated by right ventricular wall involvement in the context of congenital heart disease. Long-term follow-up is essential to monitor for recurrence and assess cardiac function and valve integrity. Surgical intervention may be necessary in selected cases to address both the infective process and underlying structural abnormalities.

 

Dr S Aravindha kumar

Dr. S. Aravindakumar
Chief Consultant Interventional Cardiologist