Infective Endocarditis Due to Streptococcus agalactiae Complicated by a Complete Atrioventricular Block

Area of Science:

• Cardiology
• Infectious Diseases
• Microbiology

Background:

• Infective endocarditis (IE) caused by Streptococcus agalactiae (S. agalactiae) is infrequently encountered but carries a high risk of mortality.
• Early diagnosis and treatment are crucial for managing IE, yet complications can still arise.

Observation:

• A 79-year-old female presented with non-specific symptoms including fatigue and appetite loss.
• Diagnosis of S. agalactiae IE was confirmed via blood cultures and transesophageal echocardiography revealing vegetations.
• Despite initial antibiotic treatment, the patient developed a sudden complete atrioventricular block.

Findings:

• Surgical intervention was required, involving abscess drainage and aortic/mitral valve replacement.
• Intraoperative findings indicated that inflammation from the endocarditis had spread to the cardiac conduction system, causing the heart block.
• This case underscores the aggressive nature of S. agalactiae in causing severe cardiac damage.

Implications:

• Clinicians must maintain a high index of suspicion for S. agalactiae endocarditis, even with atypical presentations.
• The insidious extension of perivalvular inflammation to the cardiac conduction system highlights a critical complication pathway.
• Increased vigilance and prompt surgical consideration may be necessary for patients with S. agalactiae IE experiencing conduction abnormalities.