Acute Confusion Clinical Scenarios

Posted in Med Surg

In this article we’ll explore four common cases of acute confusion (AKA delirium) in the hospital setting. Note these are not the only cause of acute confusion, and all cases of confusion should be evaluated thoroughly. You can review these four common cases of acute confusion in episode 369 of the Straight A Nursing podcast from your favorite podcast platform.

Patient #1: Phyllis

Phyllis is a 76 year old widowed female with a PMH of atrial fibrillation, hyperlipidemia, hypertension, Type 2 diabetes, migraine, cholelithiasis, and post-operative nausea/vomiting (PONV). Home medications are taken each morning and include apixaban, simvastatin, metoprolol, metformin, multivitamin, and Omega-3 fish oil capsules.

Phyllis recently fell at home and was brought to the ED at 0530 this morning for severe hip pain. X-ray showed a fracture of the femoral head and she underwent surgical repair at 0830. To help prevent PONV, the anesthesiologist administered 10 mg dexamethasone as well as 4 mg ondansetron prior to reversing the anesthetic.

In PACU she received 50 mcg fentanyl, 10 mg oxycodone, and 4 units of insulin for a blood glucose level of 215. Since arriving from PACU at 1115, she has been awake, oriented, and communicative. Pain has been controlled with hydrocodone and ice. Unfortunately, she has been complaining of nausea throughout the shift. For this she has received one dose of ondansetron and one dose of metoclopramide. You’ve been encouraging small sips of water and utilizing other interventions to relieve nausea including a cool cloth to the forehead and slow, deep breathing. She declined lunch and it is now 1830. You enter the room and notice she has not eaten dinner.

You ask Phyllis if the nausea has returned and she looks at you with confusion saying, “Where’s my husband?” and “Who changed my bedroom around?” You ask Phyllis some clarifying orientation questions and while she is able to state her name, she does not know where she is, she is unaware she had surgery, and cannot state the year.

What is your priority assessment?

When a patient taking antidiabetic medications experiences acute confusion, the first thing to check is a blood glucose level. You check Phyllis’ blood glucose and see get a result of 38.

Considering this data, what is your priority intervention?

With a confused patient, your first intervention is safety. STAY WITH THE PATIENT. Call a coworker and ask them to bring the dextrose. For a blood glucose level this low, we are going to administer IV dextrose, rather than have the patient drink some juice or eat some crackers. We’ll administer the dextrose, stay with Phyllis, and re-check her blood glucose level in 15 minutes.

Why do you think Phyllis had this particular problem?

Looking back at Phyllis’ medications, you notice she takes them all in the morning. It is likely she took her metformin before coming to the hospital. She subsequently received insulin in the PACU and hasn’t eaten anything all day. Oral antidiabetics and insulin carry a high risk of hypoglycemia, especially when PO intake is low.

Why didn’t Phyllis display the common signs and symptoms of hypoglycemia?

Beta blockers can mask the signs and symptoms of hypoglycemia, and we suspect Phyllis took her metoprolol just prior to falling this morning.

Why was Phyllis’ blood glucose elevated in PACU?

There are two key reasons Phyllis’ blood glucose level was elevated in PACU. One is the body’s stress response and the other is that she received dexamethasone to prevent nausea and vomiting. Dexamethasone is a corticosteroid and it definitely raises blood glucose levels.

Patient #2: Stanley

Stanley is an 84 year old male with a PMH of hypertension, COPD, OA, BPH, diverticulosis, and cataracts. He developed severe abdominal pain while having dinner at his daughter’s house and was brought to the ER. Stanley was found to have a small bowel obstruction which was repaired in surgery. Prior to surgery, the anesthesiologist performed an ESP block (erector spinae plane block) which can provide pain control for up to 24 hours, though the range varies widely from patient to patient. Pain was well controlled in the PACU and Stanley arrives to his room at 0115.

At 0430 Stanely’s daughter comes to the nurses’ station to inform you her dad is experiencing 5/10 pain. You administer 2 mg morphine and stay with Stanley for a few minutes to ensure he is not oversedated or experiencing respiratory depression.

After about 30 minutes the daughter returns to the nurses’ station to inform you her dad is now experiencing itching, which is troublesome enough that it is keeping him awake. You administer 25 mg diphenhydramine IV and assure Stanley and his daughter that this will take care of the opioid-induced pruritus and allow him to get some rest.

Twenty minutes later, the daughter calls out for help. You hurry into the room to see Stanely trying to get out of bed stating he “has to get to the bakery before the good donuts are all gone.” He is able to state his name, but is disoriented to time, place, and situation. Thankfully he does recognize his daughter as someone he knows, but keeps calling her by his ex-wife’s name. With some effort, you and Stanley’s daughter are able to convince him to get back to bed, though he continues to be restless and confused.

What is likely causing Stanley’s confusion?

Considering the timing of the confusion’s onset, the combination of diphenhydramine and morphine is the likely cause. All opioids can cause acute confusion in patients of any age, though the risk is higher in the elderly. Diphenhydramine has anticholinergic properties which can (and often do) cause acute confusion in the elderly. Taken together, the risk is much higher.

What else would you want to assess with Stanley?

Though we’re pretty sure the culprit is medication, we can also check a blood glucose level, oxygen saturation level, and do a quick neuro assessment to evaluate if Stanley is having stroke symptoms. Thankfully, blood glucose is WNL, SpO2 is 98% on RA, and your BEFAST assessment reveals nothing that indicates stroke. Whew!

Many medications can cause acute confusion, especially in the elderly. The Beers List is a compilation of medications that are known to be at high-risk for causing harm in the elderly, and confusion is certainly a complication we are concerned about. Other medications that can cause acute confusion in the elderly are tricyclic antidepressants, antipsychotics, benzodiazepines, and meperidine. Learn more about the Beers list here.

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Patient #3: Bob

Bob is a 64 year old male with a PMH of HTN, COPD, PVD, recurrent cellulitis, and CAD. He is in the hospital for a COPD exacerbation and pneumonia. When you first come on shift at 1900, Bob’s VS are as follows: HR 72, RR, 14, SpO2 93% on 2L NC, BP 142/76, T 36.8° C. You administer his 2100 meds and get Bob tucked in for a good night’s sleep.

Around 0200 you enter Bob’s room to take a set of VS. You notice he’s removed his nasal cannula, taken off his gown, and is currently stuck at the bottom of his bed trying to get untangled from the blankets. At least he hasn’t also removed his IV! What ensues is an hours-long struggle to get Bob to wear his oxygen, leave his clothes on, and stay in bed. Every time you get him settled, he quickly becomes restless and agitated again. He knows his name, knows he’s in the hospital, but doesnt know why he’s there or what day it is.

What assessment data do we want to obtain from Bob?

Since Bob is there for a respiratory disorder and has COPD, obtaining a set of VS is key, especially the SpO2. You measure the SpO2 and are shocked to see it is 81% on RA. Yikes! If we really want to get into the details of Bob’s oxygenation status, then an ABG may be utilized. An ABG tells us the oxygen level in arterial blood as well as other key information such as pH and CO2 levels.

What is causing Bob’s acute confusion?

Bob’s acute confusion is due to hypoxia. His brain is simply not getting enough oxygen. Ironically, patients experiencing hypoxia often remove oxygen-delivery devices, which allows the condition to quickly progress.

What do you expect to see on the ABG?

Since Bob has a history of COPD that has been exacerbated by his acute infection, you expect the ABG to be abnormal, especially considering his SpO2 is only 81% on RA. The PaO2 will be decreased, and the CO2 is typically elevated in patients with COPD. The increase in CO2 will cause the pH to decrease, so he may be a bit acidotic.

What is the treatment for Bob?

The treatment for Bob will depend on the CO2 level. If it’s elevated, then a common treatment is BIPAP. If CO2 is normal, we may be able to improve Bob’s confusion with oxygen administration, provided he allows the device to remain in place. Perhaps the nasal cannula is uncomfortable for Bob. If this is the case, you could try a different oxygen delivery device such as an oxymask.

Patient #4: Meredith

Meredith is a 53 year old woman with a PMH of hypothyroidism, cholecystitis, uterine fibroids, and hyperlipidemia. She presents to the ER at 1017 with a cough, shortness of breath, chest pain, and a fever. Her family tells you that she’s been confused all morning. Upon examination, she appears a bit lethargic and is disoriented to place, time and situation. You obtain a set of VS which reveal: HR 119, RR 25, SpO2 87% on RA, BP 88/63, T 38.9° C. Since you know confusion can be related to hypoglycemia, you check a blood glucose level and are surprised to see it is 215.

What is likely causing Meredith’s confusion?

Meredith is showing clinical signs of sepsis. Not only does she have a known infection, she has tachycardia, tachypnea, decreased SpO2, hypotension, a fever, confusion, and hyperglycemia.

What is the treatment for Meredith?

While the treatment for sepsis can be complex, the key things are source control (when possible), fluids, and antibiotics. In addition, Meredith is going to get blood cultures and a sputum culture obtained and it’s vital we do this prior to starting the broad-spectrum antibiotic. We’ll also support oxygenation with supplemental O2, treat fever and pain, and get her admitted as soon as possible. Of course, sepsis can be highly complex and challenging to treat. To learn more about this condition, click here to explore the components of the sepsis bundle.

I hope these scenarios taught you a bit about some common causes of acute confusion and how to respond. Remember, there are many more causes, so it’s always important to evaluate your patient thoroughly. Never brush off a change in mental status as it means something unexpected is happening with your patient.

Want to explore these topics further?

Learn about delirium in this article.
Dive into hypoglycemia here.
Explore the sepsis bundle here.

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References:

Hénon, H., Lebert, F., Durieu, O., Godefroy, O., Lucas, C., Pasquier, F., & Leys, D. (1999). Confusional State in Stroke. AHA, 30(4). https://www.ahajournals.org/doi/10.1161/01.STR.30.4.773

IHSS Training Academy. (n.d.). Medications that Can Cause Confusion in Elderly Persons. California Department of Social Services. https://www.cdss.ca.gov/agedblinddisabled/res/VPTC2/10%20Medication%20Management/Medications_That_Can_Cause_Confusion_in_Elderly.pdf

Johns Hopkins Medicine. (2023, December 14). Polypharmacy in Adults 60 and Older. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/wellness-and-prevention/polypharmacy-in-adults-60-and-older

NHS.UK. (2017, October 18). Sudden confusion (delirium). NHS.UK. https://www.nhs.uk/conditions/confusion/

Last Updated on May 25, 2026 by Maureen Osuna, MSN, RN