Bacterial brain abscess in patients with nasopharyngeal carcinoma following radiotherapy: microbiology, clinical features and therapeutic outcomes

Abstract

Background: This study aimed to analyze the clinical features, causative pathogens, neuro-imaging findings, and therapeutic outcomes of bacterial brain abscess in patients with nasopharyngeal carcinoma (NPC) following radiotherapy.

Methods: NPC patients with bacterial brain abscess were evaluated. Their clinical data were collected over a 22-year period. For comparison, the clinical features, causative pathogens, neuro-imaging findings, and therapeutic outcomes between NPC and non-NPC patients were analyzed.

Results: NPC accounted for 5.7% (12/210) of the predisposing factors, with Viridans streptococci and Staphylococcus aureus as the two most common causative pathogens. Significant statistical analysis between the two groups (NPC and non-NPC patients) included chronic otitis media (COM) as the underlying disease, post-radiation necrosis by neuro-imaging, and the temporal lobe as the most common site of brain abscesses. The fatality rate in patients with and without NPC was 16.7% and 20.7%, respectively.

Conclusions: NPC patients with bacterial brain abscess frequently have COM as the underlying disease. Neuro-imaging often reveals both post-radiation necrosis and the temporal lobe as the most common site of brain abscesses, the diagnosis of which is not always a straightforward process. Radiation necrosis can mimic brain abscess on neuro-imaging and pose significant diagnostic challenges. Early diagnosis and treatment is essential for survival.

Figure 1

(A) Pre-contrast axial T1-weighted MR revealed multiple left temporal lesions with hypo-intense central cavity and moderately hypo-intense surrounding edema.(B) T2-weighted and (C) fluid attenuated inversion recovery (FLAIR) axial MR revealed multiple hyper-intense lesions and surrounding hyper-intense edema. (D) Diffusion-weighted MR demonstrated high signal intensity, with (E) a corresponding reduction in the apparent diffusion coefficient. This was directly related to the cellularity and viscosity of the pus contained within the abscess cavities. In contrast, tumors with central necrosis had an appearance of marked hypo-intensity on diffusion-weighted images and hyper-intensity on the apparent coefficient map. (F) Post-gadolinium T1-weighted scan showed thick ring enhancement and increased enhancement of the adjacent dura