Delirium diagnosis in the patient who is too sleepy to speak
You approach a patient’s bedside with the aim of doing an assessment for delirium. The first thing you notice is that the patient is very sleepy, and they do not respond verbally to your greeting and a touch on their shoulder. They open their eyes for a few seconds, but they show no other response. They do not produce any speech.
What is your opinion: is assessment for a delirium diagnosis possible in this patient?
One of the controversies in delirium assessment is how we handle drowsiness in the diagnostic process. Especially when the patient is unable to produce speech.
Terms like stupor, obtundation, and so on, were advocated by some as a kind of intermediate stage between coma and delirium.
This issue was forced out into the open at around the time of publication of the DSM-5 criteria for delirium.
The DSM-5 criteria for delirium
A. A disturbance in attention (i.e., reduced ability to direct, focus, sustain, and shift attention) and awareness (reduced orientation to the environment).
B. The disturbance develops over a short period of time (usually hours to a few days), represents a change from baseline attention and awareness, and tends to fluctuate in severity during the course of a day.
C. An additional disturbance in cognition (e.g., memory deficit, disorientation, language, visuospatial ability, or perception).
D. The disturbances in Criteria A and C are not explained by another preexisting, established, or evolving neurocognitive disorder and do not occur in the context of a severely reduced level of arousal, such as coma.
E. There is evidence from the history, physical examination, or laboratory findings that the disturbance is a direct physiological consequence of another medical condition, substance intoxication or withdrawal (i.e., due to a drug of abuse or to a medication), or exposure to a toxin, or is due to multiple etiologies.
Criterion D seems to imply that as well as coma that there could be other forms of severely reduced level of arousal. However, the DSM-5 Guidance Notes went on to clarify this:
Normal attention/arousal, delirium, and coma lie on a continuum, with coma defined as the lack of any response to verbal stimuli. The ability to evaluate cognition to diagnose delirium depends on there being a level of arousal sufficent for response to verbal stimulation; hence, delirium should not be diagnosed in the context of coma (Criterion D).
Many non-comatose patients have a reduced level of arousal. Those patients who show only minimal responses to verbal stimulation are incapable of engaging with attempts at standardized testing or even interview.
This inability to engage should be classified as severe inattention. Low-arousal states (of acute onset) should be recognized as indicating severe inattention and cognitive change, and hence delirium.
They are clinically indistinguishable from delirium diagnosed on the basis of inattention or cognitive change elicited through cognitive testing and interview.
Drawing from the DSM-5 Guidance Notes and other sources, the consensus in the field is now that terms like ‘stupor’ are unhelpful. There are essentially three states in this context: coma, delirium with reduced level of arousal, or a normal level of arousal (with or without delirium or other cognitive impairment).
Do we need cognitive test scores when diagnosing delirium?
Cognitive testing is helpful in determining if there is inattention, and also also other cognitive deficits. However when person is unable to engage with the practitioner such they can understand what is being said and then respond meaningfully, they are not capable of performing cognitive tests.
If you are using a test that requires some cognitive test scoring the risk here is that the test will be abandoned. The ‘Unable To Assess’ (UTA) result, which can leave the patient without a test result and in diagnostic limbo.
The DSM-5 guidance clearly states that when there altered arousal of a severity that makes cognitive testing or even a basic interview impossible, that this should be considered ‘severe inattention’.
So the answer is that we do not need cognitive test scores as such when the person cannot do the cognitive tests at all. I would consider complete inability to produce any meaningful answers as indicating a score of zero (or whatever indicates the lowest possible score).
This conclusion has major patient safety implications. That is, when a diagnosis of delirium is made this opens up access to a process in which the causes are considered and treated, the patient’s distress is assessed and treated if needed, and so on. The diagnosis matters.
The alternative is a mixture of vague terms like ‘altered mental status’, ‘encephalopathy’, and so on, being used, mostly without a clear pathway to investigation and treatment being stimulated.
This issue was covered in a very important joint statement by the European Delirium Association and the American Delirium Society, published in BMC Medicine in 2014. It is well worth a read.
Altered arousal is a highly specific sign of delirium
Helpfully, not only is a severely reduced level of arousal (above the level of coma) consistent with delirium, it is highly specific to delirium. In fact, going through the delirium literature one can find evidence of this, e.g. in the original Confusion Assessment Method (CAM) paper:
And also in the original 4AT paper:
There are other studies that have specifically tested level of arousal as a sign of delirium, and these have also found the same results. A list can be found under the LEVEL OF ALERTNESS/AROUSAL COMPONENT section of www.the4at.com/references. This is important because chronically low arousal is unusual, especially in the context of hospital care. Altered arousal is usually acute, and it usually means that the person fulfils criteria for delirium.
The clinical implication is that not only should a patient who is too sleepy to speak be considered assessable for delirium, they very likely have delirium.
The ‘Unable To Assess’ (UTA) problem in delirium assessment
Some delirium testing processes result in lots of ‘Unable To Assess’ ratings. As we have seen from the above, many non-comatose patients with reduced level of arousal will fulfil criteria for delirium.
Note that in the CAM-ICU testing process a RASS score of -4 of -5 is termed UTA, but only because these scores are taken to indicate that the person has a coma.
My take: there should be no UTA ratings on tests in patients with clinically diagnosable delirium. Yet UTA ratings are commonly seen, especially with tests that rely on cognitive testing or interview content to determine if a patient has inattention.
I will be covering UTA in delirium assessment in more detail in a future blog. For now I would ask these questions: do you see in your practice a testing process giving UTAs in people with delirium? If so, should the testing process be more carefully evaluated, and modified or changed?