A new study finds that antibiotics may be linked to a serious disruption in brain function, called delirium, and cause other brain problems.

Delirium causes mental confusion that may be accompanied by hallucinations and agitation.

Although medications are often the cause of delirium, physicians often fail to suspect antibiotics.

The new study appears online in Neurology, a medical journal of the American Academy of Neurology.

“People who have delirium are more likely to have other complications, go into a nursing home instead of going home after being in the hospital and are more likely to die than people who do not develop delirium,” said author Shamik Bhattacharyya, M.D..

“Any efforts we can make to help identify the cause of delirium have the potential to be greatly beneficial.”

For the study, researchers reviewed all available scientific reports and found case reports on 391 patients, over seven decades, who were given antibiotics and later developed delirium and other brain problems.

Investigators determined a total of 54 different antibiotics were involved. The medications represented 12 different classes of antibiotics ranging from commonly used antibiotics such as sulfonamides and ciprofloxacin to intravenous antibiotics such as cefepime and penicillin.

Researchers discovered about 47 percent of identified patients had delusions or hallucinations, 14 percent had seizures, 15 percent had involuntary muscle twitching, and five percent had loss of control of body movements.

They also found abnormal electrical brain activity in 70 percent of the cases and that 25 percent of the people who developed delirium had kidney failure.

From this sample, researchers identified three types of delirium and other brain problems related to antibiotics.

One type (Type I) was characterized by seizures and most often associated with penicillin and cephalosporin. Type II was marked by symptoms of psychosis and associated with procaine penicillin, sulfonamides, fluoroquinolones, and macrolides.

Importantly, both Type I and Type II had a quick onset of symptoms, within days. Once antibiotics were stopped, symptoms also stopped within days.

Type III was characterized by abnormal brain scans and impaired muscle coordination and other signs of brain dysfunction, and was only associated with the drug metronidazole.

The beginning of noticeable symptoms took weeks instead of days. Symptoms also took longer to go away once the antibiotic was stopped.

Researchers cautioned, however, that all of the patients had an active infection that could not be ruled out as the cause of the delirium and other brain problems. To account for this, a scale used to determine that the association between antibiotic use and delirium was possible in most cases.

“More research is needed, but these antibiotics should be considered as a possible cause of delirium,” said Bhattacharyya.

“Recognition of different patterns of toxicity could lead to a quicker diagnosis and hopefully prevent of some of the negative consequences for people with delirium and other brain problems.”

Source: American Academy of Neurology/EurekAlert Warnings on medications by shutterstock.