Atypical Presentation of Illness is when an older adult has an illness or condition that doesn’t show up in the typical textbook definition/ways. – Jamie Smith, MSN, FNP

“Mrs. Jones just isn’t ‘right’ today”. Subtle, non-specific changes in an older adult may be the first sign that family members and caregivers see when an older adult is developing an illness. In today’s episode, we will talk about how changes in mental status (hypo- and hyperactive delirium) can be the first sign of an infection, how some infections are show up differently for younger and older adults (e.g., bladder infections), and how depression shows up differently for younger and older adults.

Jamie Smith MSN, FNP, in this episode of This Is Getting Old: Moving Towards an Age-Friendly World, highlights some salient points on how to recognize atypical presentations of illness among older adults.

Part One Of ‘Atypical Presentation Of Illness In Older Adults’

What Is Atypical Presentation Of Illness? 

Conventional healthcare education teaches the typical symptoms of common illnesses. However, for older adults, these common illnesses do not show up in the same way. The symptoms are usually more subtle and less specific than in younger adults and often are first noticed as a change in mental status, energy level or function (such as a fall or a new onset of losing control of their bladder (incontinence)).

Atypical Presentation of Illness means that an older adult will have little or no typical signs and symptoms that usually indicate a specific illness or diagnosis.  Failure to investigate atypical presentations in older patients, and identify the true medical problem, may result in undesirable outcomes, inaccurate diagnoses, and the wrong treatment for the illness.

Delirium is one way an illness may show up (or “present”) and has been attributed to adverse health outcomes.

The Seriousness Of Deliriousness: Delirium In Older Adults

What is Delirium?

Delirium usually develops quickly in a matter of hours or days. Thus, healthcare providers should be well aware of the signs and symptoms of delirium. Doing so may help them recognize atypical presentations of illness and at best help curtail severe medical conditions.

Delirium is characterized by a sudden change in attention, awareness, and cognition. Delirium may be hypoactive (meaning the person may be more tired or sleepy than usual but the changes in behavior are more subtle) or hyperactive (meaning the person is trying to crawl out of bed or some other active, agitated behavior).

Accurately diagnosing delirium in a patient population prone to dementia, depression, fatigue, and other conditions whose symptoms can mirror those of delirium can be challenging. It is estimated that between 32-66% of delirium cases are missed by healthcare professionals.

This failure to diagnose delirium has two significant consequences for patients.

  • First, the patient is presumed to have a condition, often dementia, that they do not have, which leads to false assumptions about prognosis and the possible ordering of inappropriate treatments.
  • Second, and of equal importance, missing the diagnosis of delirium may cause clinicians to fail to investigate its underlying medical causes.

Delirium may indicate a life-threatening condition. It carries an increased risk of functional decline and falls, cognitive decline, recurrent hospitalizations, and mortality. In addition, it can take months to clear, and some older adults may never regain their prior functional level.

What does Hypoactive Delirium look like?

Symptoms Of Hypoactive Delirium

Hypoactive delirium is often missed because it doesn’t create a problem for others – basically, this type of delirium is characterized by reduced motor activity, sluggishness, seeming to be in a daze, lack of interest in anything,  and reduced alertness. Symptoms in older adults include:

  • The person “isn’t right” – a sudden change in thinking/ mental status, tired (lethargic), staying in bed.
  • May or may not have a fever
  • Change in baseline vital signs (heart rate, weight loss, change in appetite)

Things that can cause hypoactive delirium include:

  • Constipation
  • or an underlying infection

Symptoms Of Hyperactive Delirium:

Hyperactive delirium gets attention! This type of delirium is characterized by increased motor activity, wandering hyper alertness, rapid speech, irritability, and combativeness. Among older adults, common symptoms include:

  • Behaviors are trying to get out of bed, fighting, fluctuating mental status.

Things to consider when trying to identify the underlying cause of either h

  • Water depletion (dehydration)
  • Infection
  • Laboratory results which are abnormal (hyponatremia, WBCs)
  • Drugs: delirium is sometimes the direct effect of medication (new medications, toxicity, adverse effects). With that, you can use Beers Criteria for Inappropriate Medication Use in Older Patients to check for polypharmacy.

Part Two Of ‘Atypical Presentation of Illness in Older Adults’

Examples Of How Infections Present Differently …


Younger Adults:  Usually have the textbook or typical symptoms for pneumonia such as fever, cough, having trouble breathing (shortness of breath), and their vital signs will be different.

Older Adults: The onset of pneumonia in older adults usually starts when “she’s not right”. There may be a sudden incontinence, they may be unusually tired, and/or they may falls. You often will NOT see a fever.  They may or may not have a cough, but hypoxia (low oxygen) and tachycardia (heart rate over 100 beats per minutes) are expected.


Younger Adults: With UTI, textbook symptoms are experiencing pain or burning with urination, having an abnormal frequency and urgency in urination, and/or flank pain. There may also be blood in the urine as analyzed on laboratory assessments—this isn’t usually visible with the naked eye.

Older Adults: A TUI in an older adult may show up as a sudden loss of bladder control and/or a change in mental status. They may be unusually tired or  may fall.


Younger Adults:  Manifestations of depression among younger adults can be more easily diagnosed through their apparent behaviors.  They can be directly asked or may say they are depressed.

Older Adults: On the other hand, older adults may be less social and many have more stigma around mental health. Symptoms include changes in appetite, flat affect, weight loss or gain, change in functional status, pain without an identifiable underlying cause (e.g., pain due to a fall, injury). Medications may cause depression for older adults; or it can be situational, like a grief process or adjustment to living arrangements.

As health care providers, the best way to diagnose depression in an older adult is sitting with the older adult, engaging them in a conversation, and asking them if they’re “feeling sad or blue”.

With older adults, I have learned from speaking with my doctors and peers not just to come out and ask, are you depressed? Because a lot of times, they shut down when you ask him that question. So I sit down with them and  notice little cues that let me know that they’re depressed.
 Jamie Smith MSN, FNP

About Jamie Smith MSN, FNP

Jamie Smith MSN, FNP, is the author of Geriatric Notes. This pocket guide has been recommended and adopted into several nursing programs across the US and won the 3rd place award with the American Journal of Nursing in 2019 (under Gerontologic Nursing). She is a full-time practicing NP in long-term care, trains new clinicians, precepts NP students, and is the Director of Education at Premier Geriatric Solutions.

Geriatric Notes by Jamie Smith MSN, FNP:
The Story Behind A Very Helpful Book

Jamie worked five years as a nurse. But she was a geriatric nurse first before becoming a nurse practitioner. New to the profession, she was utterly overwhelmed. So to help cut back on her stress, she ended up carrying a book around—some textbooks like Hazard’s Geriatric Medicine, which is a great source. She knew after a while that she couldn’t keep toting around bulky and massive resources with her.

Consequently, Jamie started making notes of good stuff that the textbooks pointed out that she would need to quit, especially when she’s seeing 20 or 30 patients a day. She wanted to see what she wanted to have handy. So she took everything that she wrote down off to the side and turned it around, made it into a pocket and got it published. Jamie was glad it worked out the way it did because universities across the United States are using it for their students and employees.

Jamie’s book is available here:
**Use the Code: GERIATRIC to save 20% plus free shipping.



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