Table of Contents

What is Delirium?

Delirium is an acute failure of brain function. The term Delirium, from latin Delirare (deviate from the furrow), describes a syndrome of acute alterations in attention, consciousness, and cognition. Delirium is also referred to as:


Altered Mental Status (AMS)


Altered Level of Consciousness (ALOC)

Hepatic Encephalopathy

Acute Brain Failure


How Common is Delirium?

Prevalence rates vary depending on age, setting, and study but are as high as 70-87% in ICU patients, 15-53% in postoperative elderly patients. Surprisingly, delirium may occur in 10-31% of patients admitted to a medical hospital. 


What are common Signs and Symptoms of Delirium?

  • Acute change (hours to days) in consciousness and attention that commonly fluctuates (wax and wane) over time
  • Marked impairment of attention (most delirious patients are unable to perform simple attention tasks)
  • Cognitive deficits 
  • Memory impairment (usually limited to recent memories and formation of new memories)
  • Disorientation to time and place but rarely to self
  • Speech and language disturbances
  • Perceptual disturbances such as illusions and hallucinations 
  • Delusions


What is the Pathophysiology of Delirium?

The pathophysiology of delirium is currently unknown. However, Delirium is likely a final common pathway involving inflammatory mediators (cytokines), hormones, and dysregulation of aminergic, cholinergic, glutamatergic, and GABAergic neurotransmission. Delirium is always attributable to a medical or organic cause and is thought to result from both predisposing and precipitating factors


Predisposing Factors

History of delirium increases the risk for another episode

Advanced age

Neurocognitive disorders (Dementia)


Any neurological insult (Stroke, Traumatic Brain Injury)

Alcohol Abuse

History of Delirium Tremens

Sensory impairment (especially hearing/vision)

Recent surgery (especially neurosurgery, cardiac, and transplant)

Intensive Care Unit (ICU) stay

Sleep deprivation


Precipitating Factors

Infections: Urinary tract infections (UTI), Pneumonia, Sepsis, Encephalitis, Meningitis, HIV/AIDS

Hypoperfusion/Hypoxia: Significant blood loss/volume loss (bleeding), Heart failure, cardiac arrest, arrhythmia, Cerebrovascular Accident (CVA), Anemia (sickle cell, B12 def, Folate def, Iron def)

Metabolic Derangement: Hypoglycemia/Hyperglycemia, Hyponatremia/hypernatremia, Uremia, Hyperammonemia

Increased Intracranial Pressure: Cerebral edema, Tumors/Mass lesions, Intracranial Hemorrhage, Hypertensive crisis



Autoimmune diseases: NMDA Receptor Encephalitis, Lupus Cerebritis

Tacrolimus (Posterior Reversible Encephalopathy Syndrome)






Lithium toxicity

Valproic Acid toxicity

TCA toxicity

Serotonin Syndrome

Neuroleptic Malignant Syndrome (NMS)

Illicit Drugs: Alcohol intoxication/withdrawal, Wernicke-Korsakoff Syndrome, Inhalant Intoxication, Opioid intoxication/withdrawal, Marijuana Intoxication, Synthetic cannabinoids (K2, Spice), Synthetic Cathinones (bath salts), PCP, LSD, Psilocybin


Who is at highest risk for delirium?

Elderly (>60 years old)

Cognitively Impaired Patients

Patients with history of CVA

Post-op patients

Sensory Impaired patients (blind, deaf)

ICU patients

Patients with multiple medical conditions

Patients with sepsis


How do you screen for delirium?

Screening Tools for High Risk Patients include the Confusion Assessment Method (CAM), Confusion Assessment Method for the ICU (CAM-ICU), Intensive Care Delirium Screening Checklist, Delirium Rating Scale, Memorial Delirium Assessment Scale, and the Nursing Delirium Screening Scale (NuDESC).

Delirium can be prevented by using various strategies that reduce a patient’s risk. These prevention strategies include Close observation (1:1 sitter), Fall precautions, and enhancing social interaction by engaging and interacting with the patient as much as possible. In addition, it is essential to frequently reorient the patient and to be sure the time (clock), date, and location are clearly visible and accurate. Encourage family to visit as familiar faces or familiar items (pictures, blankets, etc) can be helpful in preventing confusion. It is important to correct sensory impairments by making sure the patient has his or her hearing aids and glasses. Help the patient maintain a consistent sleep/wake cycle by minimizing naps during the day. Be sure the patient has sunlight during the day and that lights are off at night. Try to minimize the disruption of sleep by reducing the frequency of vital checks during the night or opening the door multiple times. Lastly, help prevent confusion by helping the patient maintain an adequate diet and encourage ambulation and light physical activity.


How is Delirium Treated?

Delirium is reversible and should be considered a medical emergency. If the cause of the delirium is identifiable, treating the medical cause is considered the primary treatment. While treating the medical cause, continue to use the prevention strategies above while minimizing the contributing factors, reviewing the medication list for precipitants, and employ behavioral interventions. Medications may be used if behavioral interventions are unsuccessful or violence/danger is imminent. Physical Restraints are a last resort for severe agitation and violence. 




  • Haloperidol (1mg-5mg PO/IM q6hr PRN)
  • Risperidone (0.5mg-2mg PO BID PRN)
  • Quetiapine (25mg-100mg PO q6hr PRN)
  • Olanzapine (2.5mg-10mg PO/IM q6hr PRN)
  • Ziprasidone (10mg-20mg PO/IM q6hr PRN)



  • Ramelteon (8mg PO QHS)
  • Melatonin (3mg-10mg PO QHS)



  • Physostigmine
  • Donepezil (5mg PO Daily)



  • Clonidine
  • Dexmedetomidine (commonly used in ICU)
  • Ketamine