Delirium

Delirium is an important cause of confusion, with symptoms including disorientation, confused speech and bizarre behaviour. It differs from dementia in that it comes on abruptly, typically over hours or days, unlike dementia which has a more prolonged course. People with delirium generally cannot hold their attention.

When delirium co-exists in those with dementia, it can be more difficult to diagnose, but if a person appears more confused than usual, it is worth considering that they may be delirious. People with dementia are more prone to delirium and in this group delirium can accelerate the rate of progression of dementia.

The causes of delirium are myriad and include medication (as per my previous blog post), infections, and metabolic disorders e.g. low sodium and high calcium. Alcohol withdrawal causes delirium tremens which is life threatening. In older people, constipation, dehydration and even surgery are important causes of delirium. Constipation and dehydration are preventable and should be avoided. There are many other causes of delirium but only the commonest have been mentioned here.

Hypoactive delirium is characterised by lethargy, reduced mobility and reduced oral intake, as well as confusion, whilst those with hyperactive delirium exhibit agitation, restlessness and sometimes aggressive behaviour. Hospital inpatients with hyperactive delirium may be subjected to a DOLs authorisation.

Conducting a mental capacity assessment in an individual with delirium should ideally not be done as delirium is generally reversible, although it can be prolonged.

It is highly recommended that a person noted to be acutely confused or more confused than usual see their GP as soon as the change in behaviour is observed as delirium is a medical emergency which carries a high rate of mortality especially in older people.