6 - Delirium in critical care: why is it important?

Summary

Introduction

Delirium is common, especially in vulnerable elderly patients or the seriously ill, it often goes unrecognized and the pathophysiology is still unclear. So what? This chapter is all about the ‘so what’, the adverse outcomes associated with delirium. Delirium is not benign.

Often the question is ‘are patients dying with delirium or because of delirium?’ This chapter will show that both statements are true.

Severity and duration of delirium

In general, it is thought that the degree and duration of delirium will have an impact on outcomes. So patients who develop subsyndromal delirium will have better outcomes than those who meet the full criteria. This is true for both elderly medical patients and patients in intensive care. Those patients who recover from full-blown delirium before discharge will fare better than those who are admitted to rehabilitation hospitals with prevalent delirium.

This suggests that aggressively managing an episode of delirium in patients with a view to reducing the duration is a good idea; secondly that persistence of symptoms in a patient up to discharge needs to be followed up.

But as often, the evidence (scientific or statistical) is lacking… and studies are much needed!

Persistent delirium

Traditionally it has been thought that delirium is a temporary state and self-limiting even if it is not treated pharmacologically. However, as referred to in Chapter 2, some patients never recover completely and continue to demonstrate symptoms of delirium up to and following discharge.