Delirium



Delirium


Walter Knysz III

C. Edward Coffey



I. Background


A. Definitions



  • Delirium refers to a clinical syndrome characterized by a disturbance of arousal, attention, perception, and other cognitive domains, which tends to have a fluctuating course. Onset is usually (but not always) acute. Numerous disorders may cause delirium (see subsequent text).


  • Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for delirium:



    • Disturbance of consciousness with a reduced ability to focus, sustain, or shift attention



      • We prefer to think of this as a disturbance in arousal that can range from the hypoaroused (drowsy, lethargic, obtunded) to hyperaroused (agitated and hypervigilant).


    • A change in cognition (such as memory deficit, disorientation, or language disturbance) or the development of a perceptual disturbance that is not better accounted for by a preexisting, established, or evolving dementia.


    • The disturbance developing over a short period of time (usually hours to days) and tending to fluctuate during the course of the day.


  • The term “delirium” is generally considered synonymous with the term encephalopathy. Other terms found in the literature include organic brain syndrome, confusional state, acute brain failure, acute dementia, reversible dementia, cerebral insufficiency, toxic psychosis, posttraumatic amnesia, and “ICU psychosis” among others.


B. Classification of delirium



  • The DSM-IV differentiates delirium by etiology:



    • Delirium due to a general medical condition


    • Substance-induced delirium


    • Delirium due to multiple etiologies


    • Delirium not otherwise specified



  • Some authors propose two other subtypes of delirium not in the DSM-IV.



    • Hyperkinetic or hyperactive delirium is characterized by hyperarousal, hypervigilance, elevated psychomotor activity, fast or loud speech, restlessness, irritability, anger, euphoria, laughter, delusions, hallucinations, distractibility, or tangentiality. Patients suffering from hyperkinetic delirium are more likely to generate psychiatric consultation (the squeaky wheel gets the oil) for assistance in managing behavior or psychosis, or possibly the capacity to sign out of the hospital against medical advice.


    • Hypokinetic, or hypoactive, delirium is characterized by decreased arousal and psychomotor activity, lethargy, apathy, and slow or decreased speech. These patients are less likely to generate a psychiatric consultation and often when they do, it is to assess for depression. The presence of delirium in these patients tends to be underappreciated, which can result in morbidities including dehydration, medication noncompliance, pressure ulcers, and aspiration pneumonia. It is thought that approximately half the patients with delirium will experience features of both subtypes over the course of the delirium.

      Additionally, some authors describe two subtypes of delirium, namely, “acute confusional states” and “acute agitated delirium”

As noted in the preceding text, there are several classifications of delirium. Each has its usefulness with certain clinicians in certain clinical situations. Use of the DSM-IV classification is apt to be the most clear when communicating with other clinicians.


C. Presentation

The clinical syndrome of delirium typically has an acute onset (hours to days) and is manifest by a disturbance of consciousness (arousal → remember hyperkinetic/hypokinetic) with reduced ability to focus, sustain, or shift attention; a change in cognition (such as disorientation, problems with memory, or a language disturbance); or the development of a perceptual disturbance (not better accounted for by a dementing process) with an overall fluctuating course.

Keep in mind that delirium can present with a wide range of signs and symptoms including disturbances in the following:



  • Level of arousal


  • Speech and language


  • Mood (dysphoria/euphoria)


  • Affect (crying, laughing, yelling, labile, constricted, etc.)


  • Thought process (tangential, circumstantial, disorganized)


  • Thought content (paranoia, delusions)


  • Perception (illusions; hallucinations visual more than auditory, tactile, and other domains)


  • Insight and judgment


  • All domains of cognition (especially attention, orientation and memory)


Some patients may also display neurologic signs such as myoclonus, nystagmus, or asterixis.


D. Epidemiology

The incidence and prevalence of delirium depend on the definitions being used and the populations being studied. The prevalence of delirium in hospitalized patients ranges from 10% to 30%. The prevalence is higher in elderly hospitalized patients (up to 40%) and in postoperative patients (as high as 50%). Patients who have undergone a cardiotomy, hip surgery, or organ transplant are at a particularly increased risk. The prevalence of delirium in terminally ill patients who are near death has been reported to be as high as 80%.


E. Potential etiologies

There are numerous potential etiologies of delirium. It is quite common for the etiology to be multifactorial. However, on occasion, no clear etiology is identified. It is imperative to remember that just because an etiology has not been identified it does not mean the diagnosis is no longer correct. Common etiologies include substance intoxication and/or withdrawal states, polypharmacy, metabolic derangements, and infection. Table 2.1 provides a more complete (yet partial) list of etiologies.


F. Prognosis

Generally, patients with delirium whose etiology is identified and treated in a timely manner will recover without observable sequelae. Full recovery is less likely in the elderly patient population. If untreated, delirium may progress to stupor, coma, seizures, or death, depending upon its etiology. It has been reported that there is a 25% mortality rate at 6 months associated with patients suffering from delirium. It is possible that these data may be skewed by the high prevalence of delirium in terminally ill patients.

The patient with delirium may experience morbidity from decubitus ulcers, aspiration pneumonia, and increased cardiovascular stress. When delirium is associated with cognitive impairment, patients may have difficulty relating a reliable medical history, thereby making diagnosis and treatment more difficult, possibly prolonging hospitalization. Patients suffering from delirium are also at risk for posthospital institutionalization (skilled nursing facility, rehab, nursing home).


G. Risk factors

Common risk factors for delirium include the following:

Tags:
Oct 2, 2016 | Posted by in PSYCHIATRY | Comments Off on Delirium

Full access? Get Clinical Tree
Get Clinical Tree app for offline access