Abstract
INTRODUCTION: Citrobacter freundii is a rare cause of central nervous system (CNS) infections, primarily affecting neonates. In adults, cases are uncommon and often associated with high mortality rates. CASE DESCRIPTION: We describe the case of an adult male with multiple comorbidities who presented with constipation, nausea and vomiting, which rapidly progressed to altered mental status and seizures. Neuroimaging revealed gas densities within intracranial veins and evolving encephalitic changes. Cerebrospinal fluid (CSF) findings were non-specific, but blood and wound cultures identified C. freundii. Targeted antibiotic therapy with cefepime and ampicillin-sulbactam was initiated, but the patient's condition deteriorated leading to withdrawal of care, and death. Autopsy confirmed multiple cerebral micro abscesses, consistent with septic embolization. CONCLUSION: This case highlights C. freundii as a rare but fatal cause of septic encephalopathy. Diagnostic challenges arose from the atypical neurological presentation and non-specific CSF findings. The transition to cefepime was guided by concerns over C. freundii's AmpC β-lactamase production. Despite appropriate antimicrobial therapy, the patient's poor outcome underscored the challenges of managing CNS infections in relatively immunocompromised hosts. Early recognition of C. freundii CNS infections is crucial, particularly in high-risk patients. A high index of suspicion, serial imaging and tailored antimicrobial therapy are essential for optimising outcomes. Further research is needed to enhance diagnostic methods and treatment strategies. LEARNING POINTS: Septic embolization due to C. freundii can present with atypical neurological symptoms.Antibiotic selection should consider C. freundii's resistance mechanisms.