A urinary tract infection following a moderate traumatic brain injury significantly worsens cognitive impairments and triggers region-specific neuroinflammation, according to a study published recently in the Journal of Neurotrauma. Led by researchers at The Ohio State University, the animal model findings highlight an overlooked complication that affects up to 15% of adult brain injury patients within a year.
Cognitive Deficits and Neuroinflammation After Brain Injury
Behavioral tests conducted six days after injury revealed that moderate traumatic brain injury impaired spatial memory in test subjects. When researchers introduced uropathogenic E. coli bacteria—the primary cause of urinary tract infections—following the injury, those cognitive impairments were greatly exaggerated, according to first author Zachary Zimomra, a neuroscience research associate and manager of Kokiko-Cochran’s lab.
This amplified cognitive decline linked directly to delayed increases in two inflammation-related proteins across multiple regions of the injured brains. Brain immune cells appeared to respond to both the primary trauma and the subsequent bladder infection. Furthermore, bladder immune cells shifted even after brain injury alone, suggesting an unexpected vulnerability that may explain why infections frequently follow such trauma, according to senior author Olga Kokiko-Cochran, an investigator in the Chronic Brain Injury Program and the Institute of Brain, Behavior, and Immunology (IBBI) at Ohio State and associate professor of neuroscience in the College of Medicine.
Understanding Brain-Bladder Communication Channels
While clinicians recognize a neural connection governing urination, researchers are now investigating how chemical signaling bridges the brain and bladder during recovery. The team observed that one cytokine, IL-6, spiked in the blood following a brain injury but was subsequently muted by the urinary tract infection, pointing toward anti-inflammatory activity prompted by infection clearance.
“Clinically, there is something about UTI that causes a behavioral change in cognition that you don’t necessarily see from influenza or a cold or some other infection,” Zimomra said. Investigators aim to determine how cellular changes in the bladder enhance these neurological and behavioral effects over time.
Did You Know?
Urinary tract infections account for up to 20% of all hospital readmissions occurring within one year after a traumatic brain injury, according to background data cited by the research team.
Future Research and Patient Demographics
Because females are significantly more likely to experience bladder infections than males, the initial experiments utilized female mice. However, researchers emphasize that post-injury urinary infections are not restricted to females, and upcoming research will incorporate animals of both sexes to expand clinical relevance.
“Let’s not overlook UTI,” Kokiko-Cochran said. “Sometimes these common experiences that are overlooked are important, and I think we can’t presume that an infection of any sort is no big deal.”
Frequently Asked Questions
How common are urinary tract infections after a traumatic brain injury?
According to previous studies cited by the researchers, 15% of adult brain injury patients experience a urinary tract infection within a year of their injury.
What causes post-injury cognitive decline to worsen during a UTI?
Research indicates that a bladder infection triggers delayed increases in inflammation-related proteins across specific regions of the injured brain, compounding existing neuroinflammation.
Are these findings limited to female patients?
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