Delirium (Acute Confusional State)

By | February 5, 2015

Description of Medical Condition

Delirium is a neurologic complication of illness and/or medication use that is especially common in older patients. The key diagnostic features are an acute change in mental status that fluctuates, abnormal attention, and either disorganized thinking or altered level of consciousness. Delirium is a medical emergency requiring immediate evaluation in order to decrease morbidity, mortality, and health-care costs. The Confusion Assessment Method (CAM), which focuses on diagnostically important issues, is an easily used and well-validated tool for delirium screening. The CAM has been adapted for use in the ICU setting.

• While the neuropathophysiology of delirium is not clearly defined, a multi-component approach addressing multiple potential contributing factors can reduce its incidence and complications.

System(s) affected: Nervous

Genetics: None known

Incidence/Prevalence in USA: The prevalence of delirium in hospitalized older patients ranges from 10-40%, with and incidence of 25-60%. In high-risk older patients such as those with hip fracture, >50% experience delirium. Since about 1/3 of adults age > 65 are hospitalized annually in the United States, and assuming a conservative delirium rate of 20%, each year 7% of all persons age 65 or older develop delirium.

Predominant age: Older persons

Predominant sex: Male = Female

Medical Symptoms and Signs of Disease

Diagnostic criteria

• CAM: Five features indicate the presence of delirium

• First 3 along with either of the last 2 are present

– Acute onset

– Fluctuating course

– Abnormal attention and inability to sustain focus

– Disorganized thinking; problems with planning/reasoning/insight

– Abnormal level of consciousness

• Any of the following may also be present in the delirious patient, but are not diagnostically specific to delirium

– Short- and long-term memory problems

– Sleep-wake cycle disturbances
– Misperceptions, hallucinations, and/or delusions

– Emotional lability

– Tremors and asterixis

Delirium subtypes

• Four subtypes based on level of consciousness

– Hyperactive delirium (15%): Patients are loud, rambunctious, and disruptive.

– Hypoactive delirium (20%): Patients are quietly confused, and may sit in bed without eating, drinking, or moving.

– Mixed delirium (50%): Features of both hyper- and hypoactive delirium

– Normal consciousness delirium (15%): Patients have an apparently normal level of consciousness, but still display disorganized thinking (confused, irrelevant, rambling speech), along with the acute onset, inattention, and fluctuating mental state

What Causes Disease?

• Usually multifactorial; often an interaction between predisposing and precipitating risk factors. With more predisposing factors (i.e. the frailer the patients), the less severe the precipitating factors must be to produce delirium. Conversely, those with few predisposing factors (i.e. very robust patients) require a greater illness-related insult to manifest delirium.

• Consider medications strongly in searching for a cause

Risk Factors

• Predisposing risk factors: Advanced age, prior cognitive impairment, functional impairment, high BUN/Cr ratio, dehydration, malnutrition, hearing or vision impairment, or any underlying medical condition that produces frailty

• Precipitating risk factors: Severe illness in any organ system(s), need for a urinary catheter, more than three medications, pain, any adverse iatrogenic event. Medications deserve special attention — the most important include sedative-hypnotics (especially long-acting benzodiazepines, e.g., diazepam and flurazepam), narcotics (especially meperidine), and anticholinergics (especially diphenhydramine, which should not be used to treat insomnia in older persons)

Diagnosis of Disease

Differential Diagnosis

Depression (slower onset, primarily a disturbance of mood, a normal level of consciousness and fluctuates over weeks to months)

Dementia (insidious onset, memory problems, normal level of consciousness and fluctuates over days to weeks)

• Psychosis


• Initially: CBC, electrolytes, BUN/Cr, urinalysis, and chest X-ray

• If needed: ECG, ABGs, drug screen, and liver function tests

Drugs that may alter lab results: N/A

Disorders that may alter lab results: N/A

Pathological Findings



• Non-contrast head CT scan if diagnosis unclear, recent fall, receiving anticoagulants or new focal neurologic signs; or to rule out increased intracranial pressure prior to lumbar puncture

Diagnostic Procedures

• Lumbar puncture, rarely, but perform if clinical suspicion of a CNS bleed or infection is high

Treatment (Medical Therapy)

Appropriate Health Care

New delirium is a medical emergency usually deserving of evaluation in the inpatient setting

General Measures

• There is little evidence to suggest that restraints decrease the risk of falls or injury and should be used only in the most difficult to manage patients, for as brief a time as possible

• Post-operative patients should be monitored and treated for:

– Myocardial infarction/ischemia

– Arrhythmias

– Pulmonary complications/pneumonia (especially if COPD present)

– Pulmonary embolism

– Urinary or stool retention (attempt urinary catheter removal by postoperative day 2)

• The route of anesthesia (general versus epidural) does not effect the risk of delirium

Treatment is multifactorial, involving identification of contributing factors and preemptive care to avoid iatrogenic problems. Several areas of care deserve special attention in all patients:

– CNS oxygen delivery (attempt to attain the following)

– Sa02 > 90% with goal of Sa02>95%

– Systolic BP > 2/3 baseline or > 90 mmHg

– Hematocrit > 30%

– Fluid/electrolyte balance

– Sodium, potassium, and glucose normal (glucose < 300 mg/dl in diabetics)

– Treat fluid overload or dehydration

– Treat pain

– Scheduled acetaminophen at 1 gram QID if daily pain

Morphine or oxycodone for breakthrough pain if acetaminophen ineffective

– Avoid meperidine (Demerol)

– Eliminate unnecessary medications

– Discontinue or minimize benzodiazepines, anticholinergics, and antihistamines

– Eliminate medication redundancies

– Investigate new patient symptoms as potential manifestation of medication side effect

– Regulate bowel/bladder function

– Bowel movement at least every 48 hours

– Screen for urinary retention or incontinence, especially after catheter removal

– Nutrition

– Dentures used properly

– Proper positioning for meals

– Assistance with meals when necessary

– Nutritional supplements (1-3 cans daily) if intake is poor

– Temporary nasogastric tube if unable to take food orally and bowels working

– Mobilization

– Out of bed on hospital day 2 (or postoperative day 1)if no contraindications

– Out of bed several hours daily if no contraindications

– Daily physical therapy if not ambulating independently

– Daily occupational therapy if not functionally independent

– Prevention of major hospital-acquired problems

• 6-inch thick foam mattress overlay if not on a special pressure reducing bed

– Avoid urinary catheter.

– Institute skin care program for patients with established incontinence

– Incentive spirometry if bed-bound

– Subcutaneous heparin 5000 units BID if bed-bound

– Environmental stimulation

– Glasses and hearing aids if used prior to illness

– Clock and calendar

– Soft lighting

– Radio, tapes, television if desired

– Sleep

– Quiet environment

– Soft music

– Therapeutic massage

– Medication if required: trazodone 25 mg qhs prn sleep; zolpidem (Ambien) 5 mg qhs prn sleep; no diphenhydramine, no benzodiazepines


As tolerated. Early physical therapy consultation may help prevent deconditioning.

Patient Education


Medications (Drugs, Medicines)

Drug(s) of Choice

Nonpharmacological approaches are preferred for initial treatment. Medications often only treat the symptoms of delirium and do not address the underlying cause.

• Neuroleptics are the preferred medications

Haloperidol (Haldol). Initially, 0.25-0.5mg PO/IM/IV unless urgent sedation is required such as with an intubated patient

Quetiapine (Seroquel). 25mg q/day bid

• Short acting benzodiazepines, if neuroleptics don’t work or should be avoided

Lorazepam (Ativan). Initially, 0.25-0.5mg PO/IM/IV

Risperidone (Risperdal) 0.25-0.5mg

Contraindications: Avoid neuroleptics in patients with parkinsonism or Parkinson disease


• Neuroleptics may cause significant extrapyramidal problems and benzodiazepines may lead to sedation. Both may increase the risk of falls.

• Risperidone may be associated with hyperglycemia and ketoacidosis

Significant possible interactions: N/A

Alternative Drugs

Olanzapine (Zyprexa) 2.5-5.0mg

Patient Monitoring

Patients should be monitored and mental status reassessed at least daily. Other monitoring depends upon the specific medical conditions present.

Prevention / Avoidance

In patients at high risk for delirium due to age and/or frailty the approach to prevention is the same as for treatment of delirium.

Possible Complications

Falls, pres sure ulcers, malnutrition, functional decline, oversedation, polypharmacy.

Expected Course / Prognosis

Delirium is usually thought of as acute and hence usually improves with treatment of the underlying condition. However, it is not unusual for delirium to become chronic. In one study, only 42% of patients had resolution of their symptoms 6 months after discharge.


Associated Conditions

• New medicine or medicine changes

• Infections (especially lung and urine)

• Heart attack

• Stroke

• Alcohol or drug withdrawal

Age-Related Factors

Pediatric: N/A

Geriatric: Older patients are at the highest risk of delirium




• Acute confusional state

• Altered mental status

• Organic brain syndrome

• Acute mental status change

International Classification of Diseases

780.09 Alterations of consciousness, other

293.0 Acute delirium

293.1 Subacute delirium

293.89 Other specified transient organic mental disorders, other

292.81 Drug-induced delirium

290.11 Presenile dementia with delirium

290.3 Senile dementia with delirium

291.0 Alcohol withdrawal delirium

291.1 Alcohol amnestic syndrome

292.0 Drug withdrawal syndrome

See Also

Alcohol use disorders Dementia Depression Restlessness

Other Notes


CAM = Confusion Assessment Method