Leptomeningeal Salmonella Paratyphi B: An Atypical Viral-Mimicking Encephalitis in Geriatrics

Abstract

Salmonella meningitis is a rare but severe central nervous system (CNS) infection with high mortality, especially in adults. While Salmonella typhi is the predominant cause, Salmonella Paratyphi B is an uncommon but important pathogen in pediatric meningoencephalitis. Early diagnosis and treatment are critical. A 71-year-old male presented with a high-grade fever associated with projectile vomiting, severe headache and photophobia. The patient was drowsy, exhibited an altered sensorium. Neurological examination revealed neck rigidity, brisk reflexes and positive Kernig’s and Brudzinski’s signs. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis with elevated protein levels. The Widal test was positive for Salmonella Paratyphi B, and brain MRI with contrast revealed leptomeningeal enhancement. The patient was treated with intravenous ceftriaxone resulting in significant clinical improvement and complete neurological recovery at discharge. This case underscores Salmonella Paratyphi B as a critical, albeit rare, consideration in geriatric meningoencephalitis. It highlights the diagnostic utility of neuroimaging in atypical presentations and demonstrates that even without culture confirmation, a combination of serology, imaging, and clinical context can guide effective management. The report emphasizes the importance of considering uncommon pathogens in elderly patients with CNS infections to ensure timely, targeted antimicrobial therapy and prevent severe neurological sequelae.