An Adult with Atrial Septal Defect Presenting with a Brain Abscess

Area of Science:

• Neurology
• Cardiology
• Infectious Diseases

Background:

• Brain abscesses are frequently associated with congenital heart diseases that cause right-to-left shunts, such as tetralogy of Fallot.
• Atrial septal defects (ASD) typically involve left-to-right shunts and are not commonly considered risk factors for brain abscesses.

Observation:

• A 29-year-old male presented with a left posterior frontal pyogenic brain abscess.
• The patient had no prior symptoms suggestive of cardiac disease.
• Diagnostic workup for the brain abscess led to the incidental discovery of a silent atrial septal defect.

Findings:

• The case demonstrates that even 'silent' atrial septal defects, usually associated with left-to-right shunts, can paradoxically act as a source for brain abscess formation.
• This challenges the conventional understanding of ASDs as low-risk factors for brain abscesses.

Implications:

• Physicians should consider a broader range of cardiac anomalies, including atrial septal defects, when evaluating the source of infection in patients with brain abscesses.
• This case underscores the importance of a comprehensive etiological investigation for brain abscesses, irrespective of typical risk factors.
• Further research may be warranted to elucidate the mechanisms by which left-to-right shunting defects can lead to paradoxical embolism and brain abscess.