P3.N272: Relapsed bacterial meningitis in an adolescent patient with aberrant patent foramen caecum

Introduction: Recurrent bacterial meningitis is defined as two independent episodes of meningitis that are separated by a period of full recovery. In contrast, recrudescence meningitis (RBM) represents persistence of the initial infection resulting from treatment failure. Both are uncommon and could be due to anatomic anomalies of the skull, traumatic head injury with secondary CSF fistula, complement deficiency or spread from a para meningeal infection.

Case Description: A 13-year-old adolescent male presented with flu-like symptoms and altered mental status. His labs were significant for leukocytosis with neutrophilic predominance along with elevated inflammatory markers and coagulation profile. The viral panel was positive for influenza B virus. The CSF analysis was significant for leukocytosis and elevated CSF protein. CSF PCR was positive for Streptococcus pneumoniae. He improved clinically on IV antibiotics with down trending of the inflammatory markers. On day 7 of treatment, he was noted to be febrile, with prostration and emesis. Repeat labs at that time showed an increase in WBC and elevated C-reactive protein. Antibiotics were changed for a broader coverage. A thorough reading was sought of the CT and MRI scans which showed an aberrant foramen caecum to be the possible underlying cause of RBM.

Discussion: Bacterial meningitis is a life-threatening condition. It may occur following one of the three underlying mechanisms: spread from the adjacent infections, direct CNS invasion as in head trauma or via bacteremia. Recurrent bacterial meningitis may be defined as re-occurrence of the infection after it has been adequately treated. Important causes include immune deficiency, anatomic defects at the skull base or at the cribriform plate, and chronic para meningeal infections. The anatomical defects of the skull base are rare anomalies that serve as a source for repeated transmission of infectious agents leading to ongoing infection and should be the first consideration in any child with RBM or recurrent bacterial meningitis. Amongst the skull base anomalies, cribriform plates and ethmoid roof anomalies are more common. Most important long-term complications related to RBM may include but are not limited to hemiparesis, cranial nerve palsies, and seizures that can decrease the quality of life. The definitive treatment in most cases of anatomical defects is endoscopic surgical closure (1).

Conclusion: Repeated bacterial meningitis is rare and may occur in patients with underlying immune conditions or anatomic defects. Our case sheds light on patent foramen caecum as a cause of RBM in a relatively older child while undergoing antibacterial management for an episode of bacterial meningitis in the same hospital admission. This case report illustrates the necessity of timely investigating the possibility of an anatomical defect to be the underlying cause of the RBM to avoid mortality and complications.