Delirium diagnostic criteria

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vishal Khurana, M.B.B.S., M.D. [2] ; Pratik Bahekar, MBBS [3] ; Ahmed Zaghw, M.D. [4]

Diagnostic Criteria

Diagnostic and Statistical Manual (DSM-5) Diagnostic Criteria

1. Diminished focus or concentration and lack of knowledge or perception of the surroundings .

1. Developing in a brief period of time accounting to hours to days, a shift from a baseline which change in severity in it’s course.

1. Also, interference in faculties of cognition like, memory, orientation, visuospatial ability, or language).

1. 1st and 3rd criteria are not a result of any previous, current, or developing neurocognitive disorder and also not related to change in arousal status e.g. coma

1. The manifestation of the disturbances resulting as a physiological sequel of a medical condition, intoxication or withdrawal of substance(s) or medicine(s), or a toxin(s); or is due to multiple etiologies, is explained by the history, physical examination, or laboratory findings.

ICD-10 Diagnostic Criteria

Scoring Systems for the Diagnosis of Delirium in Critically Ill Patients

• Confusion Assessment Method for the ICU (CAM-ICU)

The test should be done on a sufficiently awake patient (RASS score, -3 or more)

The criteria of scoring scale:

• An acute change from mental status at base line or fluctuating mental status during the past 24 hr(must be true to be positive)
• More than 2 errors on a 10­point test of atten tion to voice or pictures (must be true to be positive)

The interpretation of scoring system:

• If the RASS is not 0 and the above two criteria are positive, the patient is delirious
• If the RASS is 0 and the above two criteria are positive, test for disorganized thinking using 4 yes/no questions and a 2­step command; >1 error means the patient is delirious; ≤1 error excludes delirium

• Intensive Care Delirium Screening Checklist (ICDSC)

Scoring Systems for the Diagnosis of Delirium in Critically Ill Patients

• Confusion Assessment Method for the ICU (CAM-ICU)

The test should be done on a sufficiently awake patient (RASS score, -3 or more)

The criteria of scoring scale:

• An acute change from mental status at base line or fluctuating mental status during the past 24 hr(must be true to be positive)
• More than 2 errors on a 10­point test of atten tion to voice or pictures (must be true to be positive)

The interpretation of scoring system:

• If the RASS is not 0 and the above two criteria are positive, the patient is delirious
• If the RASS is 0 and the above two criteria are positive, test for disorganized thinking using 4 yes/no questions and a 2­step command; >1 error means the patient is delirious; ≤1 error excludes delirium

• Intensive Care Delirium Screening Checklist (ICDSC)

Diagnosis in ICU

In the ICU, international guidelines recommend that every patient gets checked for delirium every day (usually twice or more a day) using a validated clinical tool. The two most widely used are the Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC). There are translations of these tools in over 20 languages and they are used globally in many thousands of ICUs, and instructional videos and a myriad of implementation tips are available. It is not as important which tool is used as that the patient gets monitored. Without using one of these tools, 75% of ICU delirium is missed by the practicing team, which leaves the patient without any likely active interventions to help reduce the duration of his/her delirium.

The most salient component of the definition of delirium that nurses and other healthcare professionals use at the bedside is whether or not the patient can pay attention and follow simple commands (see videos and literature). The advent of daily monitoring for delirium had led to important changes in the culture of ICUs and rounds in that the entire team can now discuss the brain and how it is doing in terms of being “on” (not delirious) or “off” (delirious) and then focus on the several most likely causes of delirium in any specific patient. Thus, it is not the monitoring itself that changes the patient’s clinical course, but rather it is this combination of monitoring and then relaying the information on rounds in the ICU that makes such a huge difference in awareness of this form of organ dysfunction and then enables a difference to be made in clinical outcomes.

Differential Diagnosis

Differential points from other processes and syndromes that cause cognitive dysfunction:

• Delirium may be distinguished from psychosis, in which consciousness and cognition may not be impaired (however, there may be overlap, as some acute psychosis, especially with mania, is capable of producing delirium-like states).
• Delirium is distinguished from dementia (chronic organic brain syndrome) which describes an "acquired" (non-congenital) and usually irreversible cognitive and psychosocial decline in function. Dementia usually results from an identifiable degenerative brain disease (for example Alzheimer disease or Huntington's disease). Dementia is usually not associated with a change in level of consciousness, and a diagnosis of dementia requires a chronic impairment.
• Delirium is distinguished from depression.
• Delirium is distinguished by time-course from the confusion and lack of attention which result from long term learning disorders and varieties of congenital brain dysfunction. Delirium has also been referred to as 'acute confusional state' or 'acute brain syndrome'. The key word in both of these descriptions is "acute" (meaning: of recent onset), since delirium may share many of the clinical (i.e., symptomatic) features of dementia, developmental disability, or attention-deficit hyperactivity disorder, with the important exception of symptom duration.
• Delirium is not the same as confusion, although the two syndromes may overlap and be present at the same time. However, a confused patient may not be delirious (an example would be a stable, demented person who is disoriented to time and place), and a delirious person may not be confused (for example, a person in severe pain may not be able to focus attention because of the pain, and thus be by definition delirious, but may be completely oriented and not at all confused).

Delirium represents an organically caused decline from a previously attained level of cognitive functioning. It is a corollary of these differential criteria that a diagnosis of delirium cannot be made without a previous assessment, or knowledge, of the affected person's baseline level of cognitive function. In other words, a mentally disabled or demented person who is operating at their own baseline level of mental ability might appear to be delirious without a baseline functional status against which to compare.