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04/04/2022

Dementia or Delirium?

Many patients with memory, thinking, language, and behavioral difficulties are misdiagnosed as having dementia, when delirium is to blame. Here's a guide to differentiating these copycat conditions.

At a Glance

  • Up to half of patients with memory, thinking, language, and behavioral difficulties are misdiagnosed as having dementia, when delirium is to blame.
  • By paying close attention to a patient’s cognitive status, asking about new changes in the ability to think clearly or focus, and performing a brief standardized screening, nurse practitioners, physician assistants, doctors, and other health care providers are in a prime position to correctly spot delirium.
  • Delirium symptoms appear suddenly, while dementia has a slower, insidious presentation.
  • Delirium is characterized by altered awareness, which primarily impacts attention, while dementia is more about deficits in memory, problem solving, and judgment.
  • With delirium, intervention should be swift and address the cause. Delirium can often be resolved within hours to days.

Dementia has no cure, but families and caregivers can take steps to help patients.

Ms. Bell, 83, arrived at the clinic with her daughter, who reported that for the past two days her mother had seemed unusually tired. The night before her clinic visit, the normally talkative senior, who had been diagnosed with dementia a few years prior, didn’t respond when her daughter asked if she knew what day it was and simply stared off into space.

After performing a thorough medical history and exam, Ms. Bell’s nurse practitioner suspected worsening dementia. But she was wrong. Had she run a nasal PCR test, she would have discovered that Ms. Bell was positive for COVID-19, and the infection was causing delirium, a state of sudden confusion induced by some sort of physical or emotional stressor.

Underrecognized Diagnosis

Many patients with memory, thinking, language, and behavioral difficulties are misdiagnosed as having dementia,1,2 when delirium is to blame. Delirium is significantly underrecognized, says Carolyn K. Clevenger, DNP, GNP-BC, AGPCNP-BC, FAANP, FGSA, FAAN, a past president of the Gerontological Advanced Practice Nurses Association and clinical director of the Emory Integrated Memory Care Clinic in Atlanta.

Delirium isn’t a disease, but rather a cluster of symptoms that include trouble maintaining focus and attention, disorientation or impaired judgment, and possible (usually visual) hallucinations.3 These symptoms can manifest when a person has an underlying illness; is dehydrated, recovering from surgery, or taking multiple medications; recently stopped taking a medication;4 or has sensory issues such as low vision or hearing impairment. Delirium is toxic to the brain and increases 12-month mortality risk, which underscores the importance of recognition and intervention, Dr. Clevenger adds.

Dig Deeper

When patients present with symptoms that could also indicate dementia, health-care providers often don’t look deeper. “Clinicians tend not to look for the underlying cause,” Dr. Clevenger says. “We just think, ‘Oh, they’re older,’ and chalk their confusion up to dementia.” Between 35% and 50% of people ages 85 and older indeed have dementia, she adds, “but the danger zone for clinicians is when we assume it’s 100%. Because even at 50%, that means half those people don’t have dementia.”

In fact, there is up to a 40% incidence of delirium among nursing home residents.5 It’s the most common surgical complication among older adults, with a 50% incidence following high-risk operations such as cardiac surgery or hip fracture repair,6 and is the most common presenting symptom in geriatric COVID-19. “Not coughing, not fever,” Dr. Clevenger says, “but delirium.”

Though delirium and dementia share several overlapping features, and clinicians frequently use the terms interchangeably, they’re distinct diagnoses, says Bhanu Gogia, MD, a vascular neurology fellow at Harvard Medical School’s Beth Israel Deaconess Medical Center in Boston.

“People with dementia are more likely to experience delirium, and age is a predisposing factor for both, but if a known dementia patient … has a new feature,” it makes sense to suspect delirium, Dr. Gogia says. That’s critical, as the condition is linked with substantial rates of cognitive deterioration7 and increased mortality,1 but delirium is actually easily reversed once the underlying cause is diagnosed and treated.

Further complicating matters, two types of delirium exist. A quarter of cases are hyperactive, characterized by restless, agitated, stereotypically “delirious” behavior.6More common, though, is hypoactive, or “quiet,” delirium, like Ms. Bell’s. “That gets missed,” Dr. Clevenger says, with caregivers and clinicians assuming a lethargic patient just “had a rough night and is tired, but that person is just as delirious as the person pulling out their IV.”

 Key Distinguishing Features

Symptoms of both delirium and dementia can fluctuate, worsening at night.1,11 But fortunately, by paying close attention to a patient’s cognitive status, asking about new changes in the ability to think clearly or focus, and performing a brief standardized screening, nurse practitioners, physician assistants, doctors, and other health care providers are in a prime position to correctly spot delirium.

Despite the aforementioned parallel symptoms, delirium and dementia—the most common causes of altered mental status in elderly patients5—have discernible differences:

Sudden onset. Delirium symptoms appear suddenly, within hours to days,8 and loved ones can typically pinpoint when they began. Dementia has a slow, insidious presentation,9 so it’s “hard to put your finger on the moment it started,” Dr. Clevenger explains. Delirium patients’ family members have told her things like: “My mom got lost driving once, but we thought she was just distracted,” or, “There was this one time she put Saran Wrap on the baked potatoes instead of foil. We thought it was strange, but assumed it was because she was cooking in a different kitchen than her own.”

Difficulty maintaining attention.Delirium is characterized by altered awareness, which primarily impacts attention, Dr. Gogia says,5 while dementia is more about deficits in memory, problem solving, and judgment. The ability to pay attention may deteriorate in the late stages of dementia, but this occurs slowly and gradually.

 Different Causes

Dementia is a progressive, irreversible neurodegenerative process resulting from the buildup of toxic proteins and other substances in the brain.5 Alzheimer’s disease causes most, but not all, dementia.(Parkinson’s disease is another cause.)10 One in nine people ages 65 and older has Alzheimer’s dementia, but the rates of all-cause dementia are higher.11

Delirium, on the other hand, is a signal that something is amiss healthwise. “It can be your body telling you you’ve had a heart attack, are in kidney failure, have appendicitis, or are hypoxic,” Dr. Clevenger says.

Other common culprits include pneumonia, urinary tract infections, dehydration, immobility, sleep deprivation, severe constipation, a history of alcoholism, uncontrolled hyper- or hypothyroidism, vitamin B deficiency, or even the psychological toll of social isolation.13 Prescribed drugs also frequently play a role in delirium, especially those with anticholinergic properties, sedating drugs like benzodiazepines or sleep-promoting drugs with names ending in PM, and narcotic analgesics.6,11

Factors such as these wouldn’t likely cause delirium in a young person with a healthy brain, Dr. Gogia says, but the wear and tear of aging increases susceptibility. Men are more prone to delirium, women to dementia.5,14

Delirium can follow a stroke, with a 2019 Stroke meta-analysis concluding that approximately one in four stroke patients will experience delirium in the acute period.13 Delirium can also develop after the stress of surgery, sometimes called “post-op confusion,” “ICU psychosis,” or “hospital dementia,” says board-certified geriatrician Leslie Kernisan, MD, MPH, a clinical instructor in the division of geriatrics at the University of California, San Francisco.

Evaluation

Delirium demands an urgent evaluation, Dr. Gogia says, while dementia is more likely to be diagnosed in an outpatient setting and requires a more detailed neurocognitive assessment. Drs. Gogia and Clevenger both note that as part of the history and physical, collecting details from the patient as well as their family and caregivers is invaluable when determining baseline mental and functional status.5

Several validated standardized assessment tools can help differentiate dementia from delirium. “These are going to be your best friend,” Dr. Clevenger says. “It’s not just about clinical judgment.” The Mini-Cog three-minute assessment can help detect dementia in its early stages. The Confusion Assessment Method is a five-minute screener to aid in delirium diagnosis. Clinicians should also consider the DSM-5 diagnostic criteria for delirium and dementia.5,15

If you suspect delirium, medical, lab (blood and urine), and imaging (brain and chest) tests pinpoint the underlying cause,3 as might a thorough medication review, including any nonprescription drugs, dietary supplements, and alcohol.6

 Treatment

With delirium, intervention should be swift and address the cause.4 Delirium can often be resolved within hours to days. In fact, if dehydration is the cause, improvement could be seen in just minutes of drinking a glass of water or juice, Dr. Kernisan says. But sometimes, it can take weeks or longer for cognitive abilities to fully recover.3,16,17During that time, antipsychotics may be prescribed to manage symptoms.18

Dementia has no cure. “Our goal is to keep the patient safe, support the caregiver, and delay disease progression,” Dr. Clevenger says. Memory-enhancing medications may be prescribed along with an emphasis on maximizing vascular brain health via aerobic exercise and blood pressure management.4

Providing structure to the day and maintaining a warm, welcoming environment can help with both dementia and delirium and may even help prevent delirium from occurring in the first place by minimizing disorientation and offering a sense of reassurance.6

References

1. Fick DM, Hodo DM, Lawrence F, Inouye SK. Recognizing delirium superimposed on dementia. J Gerontol Nurs. 2007;333(2):40-49.

2. Cleveland Clinic. Dementia. Accessed Dec. 13, 2021.
https://my.clevelandclinic.org/health/diseases/9170-dementia

3. Francis J and Young GB. Patient Education: Delirium
(Beyond the Basics). Accessed Dec. 13, 2021.
https://www.uptodate.com/contents/delirium-beyond-the-basics

4. Lippmann S, Perugula ML. Delirium or dementia?
Innov Clin Neurosci. 2016;13(9-10):56-57.

5. Gogia B, Frang X. Differentiating delirium versus dementia
in the elderly. StatPearls. Accessed Dec. 13, 2021.
https://www.ncbi.nlm.nih.gov/books/NBK570594/

6.  Marcantonio E. Delirium in hospitalized older adults.
N Engl J Med. 2017;377:1456-1466.

7. Gross AL, Jones RN, Habtemariam DA, et al. Delirium and
long-term cognitive trajectory among persons with dementia. Arch Intern Med. 2012;172(17):1324-1331.

8.  Brown TM, Boyle MF. Delirium. BMJ. 2002;325(7365):644-647.

9. Varghese R, Irfan M. Delirium versus dementia: a diagnostic conundrum in clinical practice. ePsychiatric Annals.
2017;47(5). Published online. Accessed Dec. 13, 2021.
https://journals.healio.com/doi:10.3928/00485713-20170411-02

10. Johns Hopkins Medicine. Parkinson’s Disease and
Dementia. Accessed Dec. 13, 2021. https://www.hopkinsmedicine.org/health/conditions-and-diseases/parkinsons-disease/parkinsons-disease-and-dementia

11. Alzheimer’s Association. Facts and Figures. Accessed Dec. 13, 2021. https://www.alz.org/alzheimers-dementia/facts-figures

12. Stewart MH, Arora VM. Sleep in hospitalized older adults. Sleep Med Clin. 2018;13(1):127-135.

13. Shaw RC, Walker G, Elliott E, Quinn TJ. Occurrence rate
of delirium in acute stroke settings: systematic review and
meta-analysis. Stroke. 2019;50(11):3028-3036.

14. Alzheimer’s Association. Women and Alzheimer’s. Accessed December 13, 2021. https://www.alz.org/alzheimers-dementia/what-is-alzheimers/women-and-alzheimer-s

15.  Alagiakrishnan K, Xiong GL. Delirium Clinical Presentation. Medscape. Accessed Dec. 13, 2021. https://emedicine.medscape.com/article/288890-clinical#b4

16.  Kernisan L. 10 things to know about delirium. Better Health While Aging. Accessed Dec. 13, 2021. https://betterhealthwhileaging.net/what-is-delirium-10-things-to-know/

17. Saczynski JS, Marcantonio ER, Quach L, et al. Cognitive trajectories after postoperative delirium. N Engl J Med. 2012;367(1):30-39.

18. Nikooie R, Neufeld K, Oh E, Wilson LM. Antipsychotics for treating delirium in hospitalized adults. Ann Intern Med. 2019 Oct 1;171(7):485-495.

19. Mental Health America. Paranoia and delusional disorders. Accessed Dec. 13, 2021. https://mhanational.org/conditions/paranoia-and-delusional-disorders

20. Psychotic Disorders. Medline Plus. Accessed Dec. 13, 2021. https://medlineplus.gov/psychoticdisorders.html

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