What is delirium?

Let’s begin with a definition and an introduction to the common signs and symptoms of delirium, and how we can gain confidence in diagnosing it.

Delirium is a syndrome, which means a group of signs and symptoms that occur together and characterise a particular abnormality or clinical problem. Delirium classically results in changes in a patient’s cognitive function, where there is an inability to acquire and/or process information through thought, experience and senses (more of this in a minute).

Delirium results from physiological disturbances which may have a number of causes. It’s diagnosed based on clinical assessment of the patient alone, and there is no specific diagnostic test for delirium, though blood tests and other investigations may help to identify the underlying cause(s).

An everyday example of a patient at risk of delirium.

Delirium….so what?

Going back to what was said in the earlier part of this module: the surgical population is ageing and with it, diseases once considered uncommon or (more likely) unrecognised – are on the increase. Delirium is one such clinical disorder associated with patient distress, harm, and adverse outcomes.

While delirium is indeed commonly seen in surgical patients, it is not limited to surgical patients and is often seen in many ward settings. Most commonly in the surgical setting it develops a few hours to a few days after surgery, and so it may not be as familiar a condition to those working with patients immediately recovering from surgery compared to that of a POCU or ward staff member, looking after postoperative patients.

How is delirium diagnosed?

The current DSM (Diagnostic and Statistical Manual of Mental Disorders) criteria for delirium includes:

Wow, it’s not so user-friendly this DSM-V criteria, but we should spend a little time picking out the most important aspects of this and how these translate to changes in behaviour we might see in our patients in any busy day in surgery.

Lets break it down a little:

3 important features of delirium include:

3 important features of delirium. (Image credit: Dr Humphry)

The above diagram is absolutely key to understanding delirium and is an important learning point to take away this week.

Why is delirium important?

Delirium has a negative impact on patient outcomes including an increased length of POCU care and total hospital length of stay, as well as more hospital complications (e.g. falls, pressure sores). You will remember from earlier – patients with delirium postoperatively, are at an increased risk of needing admission to care homes on discharge from hospital and more likely to die earlier than those who do not develop delirium .