What is Delirium?

Delirium is another word to describe an abrupt change in mentation. It can be thought of as analogous to other acute organ failures such as heart failure, liver failure, or kidney failure. In this case, 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 may be referred to as Altered Mental Status (AMS), Encephalopathy, or Altered level of consciousness (ALOC).

How Common is Delirium?

Prevalence rates vary depending on age, setting, and study. While there is little consistency in reported prevalence rates across studies, many report rates as high as 70-87% in patients admitted to the Intensive Care Unit (ICU) and 15-53% in elderly patients after surgery. In patients admitted to medical-surgical hospitals, rates may be as high as 10-31%. These prevalence rates highlight how common this disorder is and how important it is to recognize and treat. In fact, the mortality rate of untreated delirium can be as high as 15%!

What are common Signs and Symptoms of Delirium?

The hallmark sign of delirium is an acute or abrupt change (within hours to days) in an individuals mental status. Typically, consciousness, arousal, and attention fluctuate over time (“wax and wane”) such that individuals may go through periods of apparent lucidity followed by periods of confusion. In addition to changes in consciousness, arousal, and attention, other symptoms often include:

  • Cognitive problems 
  • Memory impairment (usually limited to recent memories and formation of new memories)
  • Disorientation to time and place (but rarely to self)
  • Speech and language problems
  • Perceptual disturbances such as illusions and hallucinations (visual hallucinations are probably more common in delirium than auditory hallucinations)
  • Delusions (fixed, false beliefs such as paranoia)

What is the Pathophysiology or Cause of Delirium?

The pathophysiology or cause of delirium remains a mystery. However, delirium is probably a final common pathway with many different causes involving inflammatory mediators (cytokines), hormones, and dysregulation of aminergic, cholinergic, glutamatergic, and GABAergic neurotransmission. It is important to note that delirium is always attributable to a medical or organic cause even if the cause cannot be identified (which is often the case).

Current theory postulates that delirium results from a combination of predisposing factors and precipitating factors. That is, various factors increase the risk for developing delirium but other factors precipitate the delirious state. Think of delirium as spilling water from a cup. The predisposing factor is a cup full of water and the precipitating factor is someone bumping into you.

Predisposing Factors include

  • History of delirium increases the risk for another episode
  • Advanced age
  • Neurocognitive disorders (Dementia)
  • Depression
  • 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 include

  • 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
  • Seizures
  • Poisons
  • Autoimmune diseases: NMDA Receptor Encephalitis, Lupus Cerebritis
  • Tacrolimus (Posterior Reversible Encephalopathy Syndrome)
  • Opioids/Opiates
  • Barbiturates
  • Antihistamines
  • Anticholinergics
  • Benzodiazepines
  • 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?

  • Elderly (>60 years old)
  • Cognitively Impaired Patients
  • Patients with history of CVA
  • Post-op patients
  • Sensory Impaired patients (blind, deaf)
  • Patients in the Intensive Care Unit (ICU)
  • Patients with multiple medical conditions
  • Patients with sepsis (i.e., blood infections)

How do we 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 an individual’s risk. These prevention strategies include close observation (having someone sit with the patient), frequently reorienting the individual to their location/time/date, and enhancing social interaction by engaging and interacting with the patient as much as possible. It is important to keep visible the time (via a large clock), date, and location in case a patient forgets. Encouraging family to visit can be helpful as familiar faces or familiar items (pictures, blankets, etc) can prevent confusion.

If sensory impairments are present, these need to be addressed (such as providing hearing aids and glasses). One of the most common mistakes hospitals make is closing the curtains and turning out the lights during the day. It is essential to maintain a consistent sleep/wake cycle by minimizing naps during the day and ensuring adequate sunlight so the patient can easily estimate the time of day. Because sleep deprivation is a common precipitating factor, every effort should be made to minimize the disruption of sleep during the night. Lastly, help the patient maintain adequate nutrition and strongly encourage ambulation and/or 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 addressing the medical cause, it is important to continue to use the prevention strategies above to minimize any contributing factors. Thorough review of medications may provide insight into the cause of confusion. For example, benzodiazepines, opioids, and antihistamines are medications that can induce a confusion state in older adults and should be used judiciously. If behavioral strategies are not effective, then medications may be used to prevent harm to the patient and staff. Physical restraints should be considered a last resort for severe agitation and violence. 

Medications

Antipsychotics 

  • 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)

Melatonin Modulators 

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

Acetylcholinesterase Inhibitors

  • Physostigmine
  • Donepezil (5mg PO Daily)

Other Medication Options

  • Clonidine
  • Dexmedetomidine (commonly used in ICU)

References

  1. J. Ferrando, J. L. Levenson, & J. A. Owen (Eds.), Clinical manual of psychopharmacology in the medically ill(pp. 3-38). Arlington, VA, US: American Psychiatric Publishing, Inc.
  2. Stahl, S. M. (2014). Stahl’s essential psychopharmacology: Prescriber’s guide (5th ed.). New York, NY, US: Cambridge University Press.
  3. McCarron, Robert M., et al. Lippincotts Primary Care Psychiatry: for Primary Care Clinicians and Trainees, Medical Specialists, Neurologists, Emergency Medical Professionals, Mental Health Providers, and Trainees. Wolters Kluwer Health/Lippincott Williams & Wilkins, 2009.
  4. Focus Psychiatry Review, Dsm-5: Dsm-5 Revised Edition by Deborah J. Hales (Author, Editor), Mark Hyman Rapaport (Author, Editor)
  5. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC.
  6. Arciniegas, Yudofsky, Hales (editors). The American Psychiatric Association Publishing Textbook Of Neuropsychiatry And Clinical Neurosciences. Sixth Edition.
  7. Blumenfeld, Hal. Neuroanatomy Through Clinical Cases. 2nd ed. Sunderland, Mass.: Sinauer Associates, 2010.
  8. Higgins, E. S., & George, M. S. (2019). The neuroscience of clinical psychiatry: the pathophysiology of behavior and mental illness. Philadelphia: Wolters Kluwer.
  9. Levenson, J. L. (2019). The American Psychiatric Association Publishing textbook of psychosomatic medicine and consultation-liaison psychiatry. Washington, D.C.: American Psychiatric Association Publishing.
  10. Schatzberg, A. F., & DeBattista, C. (2015). Manual of clinical psychopharmacology. Washington, DC: American Psychiatric Publishing.
  11. Schatzberg, A. F., & Nemeroff, C. B. (2017). The American Psychiatric Association Publishing textbook of psychopharmacology. Arlington, VA: American Psychiatric Association Publishing.
  12. Neuroscience, Sixth Edition. Dale Purves, George J. Augustine, David Fitzpatrick, William C. Hall, Anthony-Samuel LaMantia, Richard D. Mooney, Michael L. Platt, and Leonard E. White. Oxford University Press. 2018.
  13. Stahl, S. M. (2013). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications (4th ed.). New York, NY, US: Cambridge University Press.
  14. Stern, T. A., Freudenreich, O., Fricchione, G., Rosenbaum, J. F., & Smith, F. A. (2018). Massachusetts General Hospital handbook of general hospital psychiatry. Edinburgh: Elsevier.
  15. Hales et al. The American Psychiatric Association Publishing Textbook of Psychiatry. 6th
  16. Goldberg & Ernst. Managing Side Effects of Psychotropic Medications. 1st 2012. APP.
  17. Benjamin J. Sadock, Virginia A. Sadock. Kaplan & Sadock’s Comprehensive Textbook of Psychiatry. Philadelphia :Lippincott Williams & Wilkins, 2000.
  18. Ebenezer, Ivor. Neuropsychopharmacology and Therapeutics. John Wiley & Sons, Ltd. 2015.
  19. Stein, Lerer, and Stahl. Essential Evidence-Based Psychopharmacology. Second Edition. 2012.
Subscribe to this Blog via Email!

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

One thought on “What is Delirium?”

Leave a Reply