Differentiating Between Delirium and Age-Related Dementia

Featured as a web exclusive in Today’s Geriatric Medicine Magazine (September 2019)

By Jason Bloome

Dementia is a fact of life for many older adults. According to the Institute for Dementia Research & Prevention, 1 in 6 women and 1 in 10 men who live past the age of 55 will have dementia in their lifetimes. Symptoms of dementia might include the inability to remember recent events, problems communicating, misplacing things, mood changes, and, when more advanced, wandering.

These symptoms can, however, be caused by other conditions that are often overlooked, resulting in patients being misdiagnosed as having dementia.

Delirium in Disguise
Delirium, for example, can masquerade as dementia. It’s caused by various factors, including chemical imbalances in the body, urinary tract infections, dehydration, malnourishment, and liver and kidney diseases. It can also be caused by use of a class of drugs known as anticholinergics, a wide-ranging group of medicines taken by an estimated 1 in 4 older adults to treat insomnia, diarrhea, asthma, Parkinson’s disease, allergies, incontinence, and various psychiatric disorders.

These drugs block acetylcholine, an important chemical messenger in the brain. Acetylcholine regulates heart rate, muscle contractions, and body secretions while dilating the blood vessels, among other functions. It plays a pivotal role in the brain for concentration, attention, memory function, and consolidation of memories.

Some prescribed medicines have strong anticholinergic properties, such as antidepressants including imipramine (brand name Trofanil), antipsychotics such as clozapine (Clozaril and FazaClo), antispasmodics such as dicyclomine (Bentyl), antihistamines such as hydroxyzine (Vistaril and Atarax), and drugs for urinary incontinence such as tolterodine (Detrol).

Anticholinergic properties are also found in many common over-the-counter drugs, including antihistamines such as Benadryl and Chlor-Trimeton and sleep aids such as Tylenol PM, Aleve PM, and Nytol.

Side effects from these drugs can include drowsiness, confusion, agitation, disorientation, difficulty in sleeping, and delirium. Doctors seeing patients with these symptoms might diagnose them with age-related dementia when they’re actually experiencing delirium caused by anticholinergics.

The Scale
When Malaz Boustani, MD, MPH, a professor of aging research at the Indiana University School of Medicine, saw a patient with all the signs of dementia, he suspected the symptoms were not age related after he began to evaluate the patient’s medicines, which included those for urinary incontinence and gastrointestinal upset as well as Benadryl (for seasonal allergies) and Seroquel (an antipsychotic medicine). To varying degrees, all the medicines were blocking acetylcholine.

Over the course of six months, the doctor and pharmacist gradually weaned the patient off the medicines while substituting alternative treatments, and almost all the signs of dementia disappeared. The patient’s score on a Mini-Mental State Exam went from 11, indicating severe dementia, to 28, in the normal range.

Based on his experiences, Boustani created the Anticholinergic Cognitive Burden List, which rates drugs based on their suspected effects on cognition.

Researchers at the Indiana University School of Medicine hope to study the link between anticholinergic drugs, dementia, and delirium with a $6.8 million grant from the National Institute on Aging.

Effects on Older Adults
Older adults in particular are susceptible to the effects of anticholinergic drugs since their bodies break down the drugs more slowly, the medicines are more likely to cross the blood-brain barrier, and their brains are less efficient in processing acetylcholine.

Anticholinergic drugs that cause delirium if taken long enough could also cause dementia, making a possibly reversible condition permanent. In the 1970s, researchers found deficits in the brains of patients with Alzheimer’s, a form of dementia, in the enzyme that processes acetylcholine. At first it was assumed that the effects of anticholinergic drugs were short-term and when the drugs were discontinued patients would return to normal. Subsequent research, however, has shown that even after they’re discontinued, anticholinergic drugs may produce long-term effects, including the death of neurons and the development of plaques and tangles associated with neurodegeneration and Alzheimer’s.

An association between anticholinergics and a heightened risk of dementia was cited in a June 2019 JAMA Internal Medicine report that studied 284,000 British adults who were 55-plus years of age from 2004–2016. The study found that more than one-half the subjects had been prescribed at least one or more of 56 anticholinergic drugs. Taking a daily dose of one of these drugs for more than three years heightened the risk of dementia by 49%. While the studies did not show that these drugs caused dementia, they did show an association.

Looking for a care home for a senior who’s been misdiagnosed with age-related dementia vs reversible delirium has life-altering consequences and fiscal ramifications for families because private-paid care homes that accept patients with dementia can be costly. Such misdiagnoses are especially tragic for low-income families who have no choice but to place their loved ones into locked skilled nursing facilities that accept Medicaid—assuming the families can even find an available bed. Most of these facilities are not secured, and those that are usually do not want long-term Medicaid patients when Medicare, for short-term stays, pays much higher rates.

Physicians need to investigate all the possible causes of a patient’s confusion before diagnosing age-related dementia or delirium, which, in some cases, can be reversed. Good detectives follow all the leads to solve the case, and, as in many crime novels, finding the right suspect is seldom as simple as it first appears. Taking a closer look at a patient who is confused might reveal a critical plot twist: The true culprit, masquerading as age-related dementia, is delirium produced by anticholinergic drugs.

—Jason Bloome is owner of Connections—Care Home Referrals, an information and referral agency for care homes for the elder population in Southern California (www.carehomefinders.com).