What is delirium and how should we handle it?
Last month, Edward Marcantonio, MD, MS, the IOA’s most recent visiting scholar and professor of Medicine at Harvard Medical School*, offered some answers to these questions during his lecture at the University of Pennsylvania.
In the 1980’s, as he was just beginning his career in the medical field, Dr. Marcantonio was taught that it was essentially “normal” for older people to go a little crazy – or “bonkers” as he calls it – during their hospital stay. The belief was that there really was not much that could be done about it, but if the symptoms became overly bothersome, prescription medications such as haloperidol or diazepam — drugs commonly used for mental or psychiatric disorders — would “take care of it.”
Today, while we are much better at recognizing what delirium actually is – and understanding that it is not “normal” – there is still some confusion across disciplines in the terminology used to identify this condition. Delirium is often referred to as acute confusional state, altered mental status, subacute befuddlement, or postoperative psychosis.
Regardless of what term is used, the diagnosis of delirium, or any of the other aforementioned names, is characterized by confusion, restlessness, and a disturbance in attention and awareness that develops acutely and tends to fluctuate. Delirium is typically referred to as one of two types—prevalent delirium or incident delirium. Prevalent delirium is when the condition is present and observed at the time of hospital admission and incident delirium develops during the hospital stay.
Delirium is even more common than most people realize. According to Dr. Marcantonio, it is experienced in 30-40% of medical inpatients over 70 years old, 15-50% of surgery patients over 70 years old, and at least 75-80% of intensive care unit patients over 18 years old.
In his line of research, Dr. Marcantonio focuses on two main aims: 1) improving delirium identification at the bedside and 2) understanding the pathophysiology of delirium and its association with dementia.
Improving delirium identification at the bedside
Because symptoms of delirium can come and go and vary in severity, identifying it can be quite a challenge. “When I got started in the field there were a number of studies that sent research teams out doing gold standard delirium assessments and then compared that to what was diagnosed in clinical care and it turned out that less than 50% of cases were recognized,” said Dr. Marcantonio.
In the 1990’s, the Confusion Assessment Method (CAM) was developed to help detect delirium in patients. The CAM looks at four key features: 1) acute change/fluctuating course, 2) inattention, 3) disorganized thinking, and 4) altered level of consciousness. In order to officially diagnose delirium according to the CAM diagnostic algorithm, the patient must be experiencing both features 1 and 2, in addition to either 3 or 4. While recognizing these features as signs of delirium can produce a successful diagnosis, there still needed to be a standardized way to identify these features in the patients. With this in mind, Dr. Marcantonio developed a series of methods and assessments for detecting delirium – some taking as little as 30 seconds to administer.
Learn more about these assessments in Dr. Marcantonio’s full lecture starting at 0:20:28:
Understanding the pathophysiology of delirium and its association with dementia
Although a variety of situations, such as dehydration, visual or hearing impairment, immobility, and sleep deprivation, can increase the chances of developing delirium, current research suggests that one of the strongest risk factors – aside from aging – is dementia.
One emerging hypothesis is that delirium may represent a state of neuroinflammation. It is believed that this neuroinflammation could be the link between delirium and dementia and if this theory is confirmed, it could have some very important therapeutic effects for both conditions.
Learn more about the link between dementia and delirium in Dr. Marcantonio’s full lecture starting at 0:40:05:
Although we have come a long way over the years to better understand delirium, there is still much work left to do. The ultimate goals are to establish effective and efficient assessments of delirium as a part of daily hospital vital sign checks and to develop pathophysiologically-based treatments to improve the short and long-term outcomes of this condition.
* Dr. Marcantonio is also the Section Chief for Research in the Division of General Medicine and Primary Care at Beth Israel Deaconess Medical Center (BIDMC).