SILENT HEARTS, DEADLY BRAINS: BRAIN ABSCESS AS A LIFE-THREATENING COMPLICATION OF UNREPAIRED TETRALOGY OF FALLOT IN A 6-YEAR-OLD CHILD — A CASE REPORT

Abstract

Introduction: Brain abscess represents one of the most catastrophic intracranial complications of cyanotic congenital heart disease (CCHD), occurring predominantly in patients with uncorrected defects characterized by right-to-left intracardiac shunting. Tetralogy of Fallot (TOF), comprising ventricular septal defect (VSD), infundibular-valvar pulmonary stenosis, right ventricular hypertrophy, and overriding aorta, constitutes the most commonly implicated CCHD subtype, accounting for approximately 61% of all cardiogenic brain abscess cases. The precise pathophysiological interplay between chronic systemic hypoxemia, polycythemia, relative iron deficiency, paradoxical embolism of septic microthrombi, and disruption of the blood-brain barrier remains an active area of investigation in pediatric neurocardiology.

Case Illustration: We report a 6-year-9-month-old male child (A.Z) born with very low birth weight (1,300 g) and neonatally diagnosed with TOF, who had not undergone corrective cardiac surgery due to economic constraints and lost follow-up for over 4 years. He presented to IGD RSUD Aji Muhammad Parikesit on June 8, 2026 with generalized tonic-clonic seizures, one month of intermittent fever, and SpO2 60% on room air. Echocardiography confirmed TOF with severe infundibular-valvar pulmonary stenosis and 1.4 cm malalignment VSD. Contrast-enhanced brain CT revealed a deep-seated cerebral abscess. On June 15, 2026, the patient underwent craniotomy with open evacuation of the deep-seated cerebral abscess, subdural drainage, and decompressive craniotomy with duraplasty, guided by neuronavigation. Post-operative course showed resolution of seizures, defervescence, and neurological stabilization. Pus and blood cultures yielded no pathogenic growth.

Discussion: This case underscores the well-established neurological vulnerability of children with uncorrected TOF. The cardinal pathomechanism involves paradoxical embolization of bacteremia-containing microthrombi through the right-to-left VSD shunt, bypassing pulmonary capillary bactericidal filtration, facilitated by hypercoagulability of secondary polycythemia and relative iron deficiency. Sterile culture results, observed in up to 61% of cardiogenic brain abscess series, add diagnostic complexity. The ESCMID 2023 guidelines recommend empirical third-generation cephalosporin plus metronidazole combined with surgical aspiration or excision for 6–8 weeks.

Conclusion: Brain abscess in uncorrected TOF represents a neurosurgical and cardiac emergency demanding immediate multidisciplinary intervention. Timely corrective cardiac surgery remains the primary preventive strategy against cardiogenic brain abscess.