Delirium may accompany 60% of the acute illnesses and adverse health events that occur commonly among nursing home residents, a new study finds. But the condition is not always easy to spot in these patients, the researchers say.

The prospective study took place in three Norwegian nursing homes over two months in 2018, and followed 145 participants. Residents with terminal illness were not included. Participants received screening for delirium when they had any acute change leading to contact with a physician.

Not only were acute events and illnesses a frequent occurrence among the nursing home residents, but 60% of the 57 who experienced an acute problem also had associated delirium. In 9 of 10 of the residents with delirium, the condition was already present when their physician was informed of the acute health event, Maria Krogseth, M.D., Ph.D., of University of South-Eastern Norway in Norway, reported.

Delirium episodes lasted for more than one week in nearly half of these patients.

Benzodiazepines link found

Most cases of delirium in the study were caused by an infection. What’s more, residents who regularly took benzodiazepine drugs or had a diagnosis of vascular dementia were more likely to experience the condition, Krogseth and colleagues wrote.

The results imply that delirium may be even more common among nursing home patients than previously reported. Caregivers may need to be especially alert for signs of the condition, they wrote. Long-term care in Norway is reserved for adults in need of continuous care and the majority of residents suffer from dementia, making diagnosis of delirium challenging, the authors noted.

“In our study, the precipitating factors for delirium were identified in all patients, except two, and illustrate the importance of searching for acute illness or troublesome conditions in patients who develop any sudden change,” they concluded.

Delirium can cause confusion or changes in mental function that is distinct from dementia but is often attributed to other illnesses. The condition comes on suddenly and can fluctuate throughout the day, according to the Mayo Clinic.

Full findings were published in the November issue of JAMDA.