Textbook of Urgent Care Medicine, Chapter 6, Altered Mental Status

Published on October 26, 2026

Original authors: Raul Rodon and Emma Rodon

Originally published in 2014. Substantially updated and clinically reviewed in 2026 to reflect current evidence, guidelines, and urgent care practice.

INTRODUCTION

Altered mental status (AMS) is a term that denotes an undifferentiated assortment of disorders of mentation that may include impaired cognition, attention, awareness, or level of consciousness. Alterations may be transient, sustained, fluctuating, or progressive.

In urgent care, the first task is not to assign a final neurologic or psychiatric diagnosis. It is to determine whether the change is acute, identify immediately reversible causes, recognize life-threatening disease, and decide whether the patient can be managed safely in the clinic or requires emergency transfer.

Delirium remains one of the most important forms of AMS seen in urgent care, especially in older adults. Dementia, intoxication or withdrawal, metabolic disease, medication effects, infection, stroke, seizure, trauma, and hypoxia are other common considerations.

PRESENTATION

AMS presents as

• Delirium
• Dementia
• Amnesia

Symptoms may include

• Acute confusion or inattention
• Somnolence, decreased responsiveness, or fluctuating level of consciousness
• Agitation, restlessness, hallucinations, or unusual behavior
• New memory difficulty or disorientation
• Focal neurologic symptoms, gait change, seizure, or postictal state

Common Risk Factors

• Older age
• Preexisting cognitive impairment or dementia
• Acute illness, dehydration, hypoxia, pain, or sleep deprivation
• Polypharmacy or a recent medication change
• Alcohol, sedative, or other drug use or withdrawal
• Renal, hepatic, endocrine, or metabolic disease

TRIAGE PEARLS

• The initial focus for all patients with AMS should be on airway, breathing, circulation, and immediate threats to life.
• Obtain a rapid bedside glucose early. Check oxygen saturation, temperature, heart rate, blood pressure, respiratory rate, and level of consciousness.
• Consider cervical spine injury when trauma is possible. Look for evidence of head injury, anticoagulant use, or an unwitnessed fall.
• Activate EMS for persistent or unexplained acute AMS accompanied by focal neurologic findings, seizure, severe headache, meningismus, respiratory depression, severe hypoxemia, shock, major trauma, persistent hypoglycemia, suspected toxicologic emergency, or agitation that cannot be managed safely in the clinic.
• Do not assume that an older patient who is quiet or sleepy is simply fatigued. Hypoactive delirium is easily missed.

HISTORY PEARLS

Mental status changes can evolve acutely, with a rapid, fluctuating, and usually transient course, as in delirium. Conversely, dementia advances insidiously and inexorably over months or years, with a gradually worsening or stuttering course.

• Establish the patient’s baseline mental status. When possible, obtain collateral history from family, caregivers, staff, or EMS because the patient may not be a reliable historian.
• Determine the exact time of onset or last known normal. Ask whether symptoms fluctuate and whether attention, behavior, speech, gait, or functional ability changed from baseline.
• Ask about recent falls, head injury, headache, seizure, fever, dyspnea, chest pain, urinary or respiratory symptoms, vomiting, diarrhea, poor intake, and new focal neurologic symptoms.
• Review all prescription, over-the-counter, and nonprescription substances. Pay particular attention to anticholinergics, sedative-hypnotics, opioids, antihistamines, muscle relaxants, anticonvulsants, psychoactive medications, insulin or sulfonylureas, and recent medication additions or dose changes.
• Ask about alcohol and benzodiazepine use and the timing of the last dose. Withdrawal may present with tremor, agitation, hallucinations, autonomic symptoms, or seizures.
• Ask about environmental exposures, including carbon monoxide, especially when more than one person is ill or symptoms improve away from a location.

Delirium

• Acute onset of AMS is characterized by impaired awareness, easy distractibility, confusion, and disturbances of perception, which may include illusions, misinterpretations, or visual hallucinations.
• There may be a recent memory deficit, with disorientation to the present time and place.
• The patient’s level of awareness may fluctuate over brief periods of time; speech may be incoherent, pressured, nonsensical, perseverating, or rambling.

• Delirium may be hyperactive, hypoactive, or mixed. Hypoactive delirium may present chiefly as sleepiness, slowed responses, poor intake, or reduced interaction and is commonly overlooked.
• If there is difficulty distinguishing delirium from dementia, treat the acute change as delirium until a reversible cause has been evaluated.

TABLE 1. COMMON CAUSES OF ALTERED MENTAL STATUS

Cause	Examples / Clues
Infection or systemic illness	Sepsis; pneumonia; meningitis/encephalitis; symptomatic urinary infection; severe viral illness.
Medication, toxin, or withdrawal	Opioids; sedatives; anticholinergics; alcohol or benzodiazepine withdrawal; recreational drugs; carbon monoxide or other toxic exposure.
Metabolic or endocrine	Hypoglycemia or hyperglycemic crisis; sodium disturbance; renal or hepatic failure; thyroid or adrenal disease; dehydration; temperature extremes.
Hypoxemia or hypercapnia	Pneumonia; COPD exacerbation; heart failure; pulmonary embolism; respiratory depression.
Neurologic	Ischemic or hemorrhagic stroke; seizure/postictal state; subdural hematoma; traumatic brain injury; CNS infection; mass lesion.
Cardiovascular	Arrhythmia; myocardial ischemia; shock; hypertensive emergency.
Psychiatric	Primary psychiatric disease is a diagnosis of exclusion when the change is acute or atypical.

Dementia

• Dementia is a chronic condition that involves a progressive decline in cognition and function.
• A patient with dementia may also develop delirium. A new change from the patient’s usual cognition, attention, or behavior should not be attributed to dementia without evaluation.
• Depression can impair concentration and memory, but the older term “pseudodementia” is imprecise. Acute or fluctuating cognitive change still requires a medical evaluation.

PHYSICAL EXAM PEARLS

• For an urgent care provider, an accurate history and comparison with the patient’s baseline are often as important as the examination.
• Assess general appearance, hydration, odor or evidence of exposure only as supporting clues; do not rely on appearance or odor alone to diagnose intoxication or metabolic disease.
• Repeat a complete set of vital signs when the first set is abnormal or the patient’s status changes.
• Perform a focused neurologic examination, including level of consciousness, speech, pupils, eye movements, facial symmetry, limb strength, sensation, coordination, and gait when safe. Any new focal deficit raises concern for stroke or other intracranial disease.
• Look for signs of trauma, infection, meningismus, respiratory failure, toxidromes, dehydration, and urinary retention or fecal impaction when clinically plausible.
• In older adults, review hearing and vision needs and look for pain, unfamiliar surroundings, and other factors that can worsen delirium.

DELIRIUM SCREENING PEARLS

The Mini-Mental State Examination was historically used to describe cognitive impairment, but it is not the preferred tool for identifying acute delirium in urgent or emergency care.

• Use a brief validated delirium assessment when feasible. Current guidance supports tools such as the 4AT or brief Confusion Assessment Method (bCAM) in older adults.
• A screening score does not replace clinical judgment. The key findings remain acute change from baseline, fluctuating course, impaired attention, and altered cognition or level of consciousness.
• If the presentation is concerning and the clinician cannot confidently distinguish delirium from dementia or psychiatric illness, transfer for further evaluation.

TABLE 2. CLINICAL FEATURES OF DELIRIUM, DEMENTIA, AND PRIMARY PSYCHIATRIC ILLNESS

Characteristic	Delirium	Dementia	Primary Psychiatric Illness
Onset	Acute, hours to days	Usually insidious	Variable
Course	Fluctuating	Progressive or stable baseline	Often more stable than delirium
Attention	Impaired	Often preserved early	Usually preserved unless severe illness/intoxication
Consciousness	May be altered	Usually alert until advanced disease	Usually alert
Hallucinations	May occur, often visual	May occur in some dementias	May occur; often organized within psychiatric syndrome
Focal neurologic findings	Not expected from delirium itself; seek structural cause	Not usually acute	Not explained by primary psychiatric illness

TESTING PEARLS

• Bedside glucose is the most important immediate test because hypoglycemia is rapidly reversible and potentially fatal.
• Testing should be directed by the history and physical examination rather than ordered as a routine “AMS panel.”
• Consider ECG when arrhythmia, ischemia, syncope, medication toxicity, overdose, or QT-prolonging drugs are possible.
• Urinalysis or urine culture should not be used to explain delirium solely because bacteriuria is present. In older adults without urinary symptoms or systemic signs of infection, look for other causes rather than treating asymptomatic bacteriuria.
• Chest radiography is useful when respiratory symptoms, hypoxemia, fever, abnormal lung findings, or aspiration are present.
• If stroke, intracranial hemorrhage, CNS infection, nonconvulsive seizure, serious toxic exposure, or other intracranial disease is suspected, the patient generally requires ED transfer for advanced testing and imaging. Do not delay transfer to complete nonessential office testing.

DIAGNOSIS PEARLS

The following questions should be considered:

• Is the AMS acute or chronic, and what is the patient’s usual baseline?
• Has there been fluctuation in its course?
• Is attention impaired or is there a reduced or altered level of consciousness?
• Is there a focal neurologic deficit, seizure, severe headache, or recent trauma?
• Could hypoglycemia, hypoxia, hypercapnia, sepsis, medication toxicity, intoxication, or withdrawal be present?
• Is there evidence of an opioid toxidrome, including respiratory depression and decreased responsiveness?
• Is delirium superimposed on known dementia?

TREATMENT PEARLS

Treatment of AMS is cause directed. In urgent care, stabilize immediately reversible problems while arranging transfer when the cause is serious, uncertain, or outside the clinic’s capabilities.

• Hypoglycemia: If the patient is awake and can safely swallow, give oral glucose. If the patient cannot safely take oral carbohydrate, treat promptly with IV dextrose according to local protocol or glucagon if IV access is not available. Recheck glucose and clinical status. Do not delay treatment of hypoglycemia while waiting to administer thiamine.
• Thiamine deficiency: In a patient with alcohol use disorder, malnutrition, bariatric surgery, prolonged vomiting, or other risk for Wernicke encephalopathy, give parenteral thiamine promptly when feasible. Transfer if Wernicke encephalopathy is suspected.
• Suspected opioid overdose: Support ventilation, give naloxone according to the available product and local protocol, repeat as needed to restore adequate breathing, and activate EMS. The goal is adequate ventilation, not necessarily complete arousal.
• Hypoxemia or respiratory failure: Give oxygen and airway support as indicated and transfer for higher-level care.
• Severe agitation: Start with verbal de-escalation, a quiet environment, and help from family or caregivers when appropriate. Avoid benzodiazepines for routine delirium in older adults unless treating alcohol/benzodiazepine withdrawal or another specific indication. If medication or physical restraint is required for immediate safety, use the least restrictive approach within local capability and arrange ED transfer.

TABLE 3. URGENT CARE MANAGEMENT OF ALTERED MENTAL STATUS

Situation	Immediate Urgent Care Action	Disposition
Hypoglycemia	Treat immediately; repeat glucose and reassess mental status.	Transfer if persistent, recurrent, severe, or cause is uncertain.
Opioid respiratory depression	Airway/ventilation support and naloxone.	EMS/ED.
New focal deficit, suspected stroke/hemorrhage, seizure, meningismus	Stabilize; note last known normal; avoid delays for nonessential testing.	EMS/ED.
Sepsis, shock, severe hypoxemia, hypercapnia concern	Oxygen/airway support, IV access if it does not delay transport, rapid transfer.	EMS/ED.
New delirium or unexplained acute AMS	Check glucose, vitals, focused exam, targeted testing only if it changes immediate management.	Usually ED evaluation.
Known dementia at usual baseline with no acute change	Evaluate the presenting complaint and caregiver concern.	Outpatient management may be appropriate if no acute medical issue is found.

DISPOSITION PEARLS

• Because of the potential for serious underlying disease, most patients with new, unexplained, or persistent acute AMS or delirium require emergency department evaluation.
• A patient whose mental status returns completely to a reliable baseline after treatment of a clearly identified minor reversible cause may sometimes be managed without transfer, provided vital signs are stable, no red flags remain, the patient has decision-making capacity, and reliable observation and follow-up are available.
• Chronic dementia alone is not an indication for emergency transfer; a change from baseline is.
• Do not permit a patient with unresolved AMS to drive. Ensure safe transport and supervision.

MEDICOLEGAL PEARLS

• Document the patient’s baseline mental status, who provided collateral history, the time course of change, vital signs, glucose, neurologic examination, and response to treatment.
• Decision-making capacity is specific to the decision and may be impaired by delirium, intoxication, dementia, or other causes of AMS. Do not assume that every patient with AMS automatically lacks capacity; document the assessment. When capacity is absent, use an appropriate surrogate or emergency exception consistent with local law and policy.
• Document why transfer was or was not required, including unresolved red flags, limitations of urgent care testing, and the patient’s clinical response.
• Consider abuse, neglect, unsafe living conditions, medication mismanagement, and caregiver limitations when relevant, and follow mandatory reporting requirements.

REFERENCES

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2. National Institute for Health and Care Excellence. Delirium: prevention, diagnosis and management in hospital and long-term care. NICE guideline CG103. Updated January 18, 2023.
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11. Rodon R, Rodon E. Altered Mental Status. In: Urgent Care Textbook. 2014. Chapter 6, pp. 55-62.