(514) Spontaneous Gram-Negative Bacillary Meningitis: A Rare Case of Pseudomonas aeurginosa Meningitis

Introduction: Pseudomonas aeruginosa is a rare cause of meningitis. Community acquired cases are uncommonly described arising from a hematogenous source. Risk factors include diabetes, alcoholism, parasitic infection and cancer. We present a case of community acquired meningitis from Pseudomonas aeruginosa.

Description: A 47-year-old woman with a significant history of alcohol use disorder and diabetes presented with altered mental status. She was febrile to 39.6, tachycardic with a GCS of 9 that further deteriorated requiring intubation. Labs were remarkable for 34% bands without leukocytosis and platelet of 48. A non-contrast head CT on admission was negative for bleed or mass effect. Lumbar puncture had 686 protein, 41 glucose, 7 WBCS, and 297 RBCs and CSF gram stain grew gram negative rods. Empiric vancomycin, ceftriaxone, and acyclovir were started. On day 2, she was transitioned to cefepime as CSF and blood cultures grew Pseudomonas aeruginosa. She underwent MRI brain that showed multiple septic embolic infarcts with associated vasogenic edema and abscesses as well as meningeal enhancement consistent with meningitis. Tobramycin was added for cerebritis and intracranial abscess. She gradually improved over 6 weeks and was discharged home with a two-week course of levofloxacin.

Discussion: Pseudomonal meningitis can be diagnostically challenging and is often described as nosocomial meningitis associated with neurosurgery. Often, it is described as a chronic and indolent course, however this patient was last seen normal the day prior to presentation. This patient also had low WBCs in the CSF. This patient was without significant surgical history prompting the team to believe that the initial gram stain result was a contaminant from the high number of RBCs in the CSF sample, however the MRI brain confirmed the diagnosis. Patients with gram negative CSF infections should undergo PCR testing to aid diagnosis and treatment. Factors such as resistance and penetration lead to significant treatment challenges in Pseudomonal CSF infections. Empiric antibiotics for community acquired bacterial meningitis do not cover Pseudomonas species and this patient had a delay in treatment highlighting pertinent considerations for choosing appropriate antibiotics in critically ill patients.