Nursing care
Delirium nursing care: what to assess and what to do first
Written and reviewed by Dana Whitfield, RN, MSN · 6 min read · Updated September 2026
Short answer
Delirium is an acute, fluctuating disturbance in attention and awareness, usually caused by an underlying medical problem such as infection, medication or metabolic imbalance. Unlike dementia, it comes on over hours to days, waxes and wanes through the shift, and is reversible once the cause is found and treated.
What it is and why it happens
Delirium is a disturbance of attention, awareness and cognition that develops over a short period, typically hours to days, and tends to fluctuate in severity across a single shift. That acute, fluctuating course is the feature that separates it from dementia, which develops over months to years and stays relatively stable day to day. A patient can be lucid at 0800 and disoriented by 1400, then improve again by evening. This is not a personality change or a baseline decline; it is a medical emergency until proven otherwise.
The underlying driver is almost always identifiable and often reversible. Common causes include infection (urinary tract infection and pneumonia are frequent culprits, especially in older adults), medication effects (opioids, benzodiazepines, anticholinergics), metabolic derangement (hypoxia, hyponatraemia, hypoglycaemia), dehydration, substance withdrawal, and post-operative states. Because the cause is treatable, delirium itself is potentially reversible, which is exactly why early recognition matters. Missing it, or writing it off as "just confusion" in an older patient, delays treatment of the underlying problem.
How it presents — what you will actually see
Delirium shows up in three patterns, and only one of them is loud. Hyperactive delirium looks like agitation, restlessness, pulling at lines, and sometimes hallucinations — it gets noticed because it disrupts the unit. Hypoactive delirium looks like lethargy, withdrawal, and reduced responsiveness, and it is frequently mistaken for tiredness, depression or the patient "just being quiet today." Mixed delirium alternates between the two. Hypoactive delirium is the one most often missed on a busy shift, and it carries a worse prognosis when it goes unrecognised.
Across all three types, the common thread is inattention: the patient struggles to focus, follow a conversation, or stay oriented to what is happening around them, and this ability fluctuates rather than staying fixed. Sleep-wake cycles are often disrupted, with daytime drowsiness and night-time agitation — the classic "sundowning" pattern. Speech may become disorganised or rambling. The patient's baseline mental status, as reported by family or documented on admission, is the reference point that makes the change visible.
Nursing assessment priorities
Establish the patient's baseline cognition as early as possible, ideally from family or prior records, because delirium is defined by change from that baseline. Use a validated screening tool at regular intervals rather than relying on a gestalt impression — the Confusion Assessment Method (CAM) is the most widely used bedside tool and asks specifically about acute onset and fluctuating course, inattention, disorganised thinking, and altered level of consciousness. Screen on admission and at set intervals through the shift, not just when something looks obviously wrong, since hypoactive presentations are easy to miss on a single glance.
Work backward from presentation to cause. Check vital signs and oxygen saturation for hypoxia, review the medication administration record for recently added or increased sedating drugs, check glucose, review labs for electrolyte and renal derangement, and assess for signs of infection including a bladder scan or urinalysis if indicated. Review the last bowel movement and bladder status, since constipation and urinary retention are underrecognised contributors. Document findings clearly and specifically, because the CAM result and the suspected precipitating factor both need to be visible to the next shift and to the physician.
Interventions and what to do first
The first priority is safety: fall precautions, close observation or one-to-one supervision if agitation or wandering risk is high, and removal or securing of lines and tubes the patient may pull at. Reorient the patient frequently and simply, stating the day, time, location and what is happening, and keep a visible clock and calendar in the room. Involve family at the bedside where possible; a familiar voice is often more effective than any pharmacological intervention at calming an agitated, confused patient.
In parallel, address the underlying cause identified during assessment: treat the infection, correct the electrolyte imbalance, hold or reduce the offending medication, and rehydrate. Non-pharmacological measures come first and should be maximised before reaching for sedation: minimise unnecessary noise and light at night, cluster care to protect sleep, ensure glasses and hearing aids are in and being used, and mobilise the patient as soon as it is safe. Physical restraints and sedating medications are a last resort, not a first response, because both can prolong or worsen delirium. If pharmacological management becomes necessary, it should be at the lowest effective dose and reviewed daily, with the goal of discontinuing as soon as possible.
Complications to watch for
Untreated or prolonged delirium carries real risk. Falls and line removal are the immediate physical dangers, particularly in the hyperactive presentation, but hypoactive delirium carries its own hazards through immobility, including pressure injury, deconditioning, aspiration and venous thromboembolism. Watch closely for both.
Longer term, delirium is associated with extended hospital stay, increased likelihood of discharge to a higher level of care rather than home, and higher mortality independent of the underlying illness that caused it. There is also growing evidence linking delirium episodes, particularly prolonged ones, to accelerated cognitive decline afterward. None of this is inevitable, but it is the reason delirium is treated as urgent rather than incidental — every day it goes unaddressed adds to the risk profile.
Patient teaching before discharge
Before discharge, talk to the patient and family together about what happened, using plain language: delirium is a temporary, treatable state caused by an illness or medication, not a sign of permanent dementia, and it should resolve as the underlying cause resolves. Patients are often distressed or embarrassed by what they said or did while delirious, and reassurance that this was the illness, not them, matters.
Teach the family to recognise early signs of recurrence — sudden difficulty concentrating, unusual drowsiness, disorientation to time or place, or a personality shift — and to seek medical review promptly rather than waiting to see if it passes. Review any medication changes made because of the delirium episode and explain why they were made, since resuming a discontinued sedating drug without medical guidance is a common route back into a second episode. If the patient had a urinary tract infection, dehydration, or a metabolic cause, give specific guidance on preventing recurrence: hydration targets, hygiene measures, or follow-up bloodwork as appropriate.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our neurological practice questions are the closest set to what this page covers.
Common questions
What is the main difference between delirium and dementia?
Onset and course. Delirium comes on acutely, over hours to days, and fluctuates through the day. Dementia develops gradually over months to years and stays relatively stable day to day. A sudden change in a patient with known dementia should still be treated as possible delirium layered on top.
Which delirium type is most often missed?
Hypoactive delirium. The patient is quiet, withdrawn and drowsy rather than agitated, so it gets mistaken for tiredness or low mood instead of being flagged and screened with a tool like the CAM.
Is delirium reversible?
Often, yes, if the underlying cause is identified and treated promptly. Infection, medication effects, dehydration and metabolic imbalance are the most common reversible causes. Delay in treatment increases the risk of prolonged symptoms and complications.
What is the first nursing priority when a patient develops delirium?
Safety first, alongside identifying the cause. Fall precautions, close observation, and reorientation happen immediately while assessment for infection, medication effects, hypoxia and metabolic derangement runs in parallel.
Should physical restraints be used for agitated delirium?
Only as a last resort after non-pharmacological measures have failed and safety cannot otherwise be maintained. Restraints and sedatives can prolong delirium and increase complication risk, so they are reviewed and discontinued as soon as possible.