Delirium causes hallucinations or agitation, and can lead to changes in alertness, consciousness, awareness, movement, sleep patterns and memory. It's often linked to alcohol or sedative drug withdrawal, drug abuse, infections, poison, surgery and medications, according to the National Institutes of Health. It occurs in up to half of hospitalized patients and up to 80 percent of ICU patients, according to the study.
Researchers from Brigham and Women's Hospital, Massachusetts General Hospital and Harvard Medical School in Boston reviewed research articles published from 1946 through 2013, describing 391 cases of patients who were prescribed antibiotics and later developed encephalopathy – an umbrella term for any brain disease that alters the structure or function of the brain, like delirium.
They identified three types of antibiotic-associated encephalopathy, or AAE, which linked the following medications to specific reactions: cephalosporins and penicillin were linked to seizures; quinolones, macrolides and procaine penicillin to psychosis; and metronidazole to abnormal MRI scans.
The researchers also found that 47 percent of people with AAE had delusions or hallucinations, 14 percent experienced seizures, 15 percent reported involuntary muscle twitching and 5 percent lost control of body movements. Brain scans were abnormal in 70 percent of the cases, and 25 percent of the people who developed delirium had kidney failure, according to a press release.
These reactions stopped once the patients were taken off the antibiotics, and while more research is needed, health care providers should consider antibiotics as the cause for delirium in some patients.