Inflammation may be the culprit behind post-surgical delirium frequently seen in frail, older adults, say researchers.

In a study using mice, investigators found that the body’s response to surgery triggers a series of events. These enable inflammation to bypass the brain’s gatekeeper: the blood-brain barrier. Once the barrier is breached, inflammation contributes to rapid beta-amyloid plaque buildup in the brain, disrupting the patient’s mental status, according to Niccolò Terrando, Ph.D., from Duke University School of Medicine, Durham, N.C.

The resulting delirium can lead to a poor recovery and greater risk of death.

“The blood-brain barrier has often been under-appreciated in the context of perioperative neurocognitive disorders, such as delirium,” Terrando and colleagues wrote.

The study was published online in Alzheimer’s & Dementia.