Possible clinical features of delirium include:
- in a hospital
- hypoactive form- most common form seen in older individuals which often goes unrecognised
- makes a person withdrawn, quiet, sleepy with additional features such as   - unawareness
- decreased alertness
- sparse or slow speech
- lethargy
- reduced/slowed movements
- reduced appetite
- apathy
 
 
- hyperactive form- makes a person restless, agitated, aggressive along with:     - increased confusion
- hallucinations (visual or auditory)/delusions
- sleep disturbance
- fast or loud speech
- irritability
- combativeness
- impatience
- uncooperativeness
- euphoria
- anger
- easy startling
- distractibility
 
 
- mixed form- most commonly diagnosed subtype
- patient may present with features of hyper and hypoactive forms
 
- in the community- an increased risk of delirium is seen in recently discharged patients sent directly to their homes
- they may experience - loss of behaviour control, mood fluctuations, episodes of frank psychosis, or agitation
 
- in long-term care facility- patients usually have hypoactive form of delirium in this setting
 
- nearing death- in the hospice or palliative care setting, patients commonly have hypoactive delirium
- usually misdiagnosed in these terminally ill patients as depression or severe fatigue (1)
 
NICE have outlined a set of indicators of delirium: at presentation (2)
- at presentation, assess people at risk for recent (within hours or days) changes or fluctuations in behaviour. These may be reported by the person at risk, or a carer or relative. Be particularly vigilant for behaviour indicating hypoactive delirium (marked *). These behaviour changes may affect: - cognitive function: for example, worsened concentration*, slow responses*, confusion
- perception: for example, visual or auditory hallucinations
- physical function: for example, reduced mobility*, reduced movement*, restlessness, agitation, changes in appetite*, sleep disturbance
- social behaviour: for example, lack of cooperation with reasonable requests, withdrawal*, or alterations in communication, mood and/or attitude
 
NICE suggest that if any of these behaviour changes are present, a healthcare professional who is trained and competent in diagnosing delirium should carry out a clinical assessment to confirm the diagnosis.
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