In a new study published today [Dec. 5, 2019] in the journal Brain, researchers at the University of Wisconsin-Madison School of Medicine and Public Health have discovered that delirium following severe surgery may be associated with brain injury.
“For a long time it has been thought that delirium, a state of confusion that can arise in sick patients, may lead to dementia and long-term cognitive problems,” says study leader Robert Sanders, assistant professor of anesthesiology at the UW School of Medicine and Public Health. “However, it has been impossible to prove that delirium causes these problems, but our study directly links inflammation during delirium with nerve injury.”
Sanders and his team were able to demonstrate that delirium is associated with injury to nervous tissue in the brain that could lead to loss of cognitive ability. The findings could inform future efforts to educate patients about the risks of surgery, especially major surgery in patients older than age 65 years.
The research team demonstrated that a protein called neurofilament light, which indicates brain injury, increased in the presence of diagnosed delirium in patients following severe surgery. Delirium is an acute state of confusion that results in inattention and cognitive failure.
Researchers examined blood samples collected from 93 participants before and after surgery, to look for changes in neurofilament light and changes to markers for inflammation. The average age of study participants was 71.
Following surgery, 39 of the participants experienced delirium, particularly those who underwent vascular surgery or other higher-risk surgeries. All study subjects who underwent surgery saw an increase in their levels of neurofilament light, but the increase was profound in the group whose members experienced delirium.
In fact, the researchers found that as delirium severity increased, so did the amount of the neurofilament light protein and signs of inflammation in the blood of participants. They also found that neuronal injury was associated with increases in delirium severity, regardless of inflammation.