What differentiates delirium from dementia?

From the Guidelines

Delirium is differentiated from dementia by its acute onset, fluctuating course, and reversibility when the underlying cause is treated, whereas dementia is a chronic, progressive neurocognitive disorder characterized by gradual decline in cognitive function that is generally irreversible. The key features of delirium include reduced awareness of the surrounding environment, poor thinking skills, and behavioral and emotional changes, which can develop over a short period of hours to days 1. In contrast, dementia is a chronic condition characterized by gradual decline in cognitive function, with features such as memory loss, personality changes, and cognitive deficits 1.

Some of the key differences between delirium and dementia include:

• Onset: Delirium has an acute onset, whereas dementia has a gradual onset
• Course: Delirium has a fluctuating course, whereas dementia has a progressive course
• Reversibility: Delirium is typically reversible when the underlying cause is treated, whereas dementia is generally irreversible
• Awareness: Delirium is characterized by reduced awareness of the surrounding environment, whereas dementia is characterized by preserved awareness

It is essential to identify delirium promptly, as it indicates an underlying medical condition requiring treatment and has significant implications for patient management during hospitalization 1. The economic impact of delirium is also profound, with total costs estimated at $38 to $152 billion each year 1.

In clinical practice, validated assessment scales such as the Richmond Agitation Sedation Scale and Glasgow Coma Scale can be employed to objectively quantify the severity of symptoms, and screening tools such as the Confusion Assessment Method (CAM) can be used to assess for delirium 1. Management of delirium is based on treatment of the underlying cause, control of symptoms with nonpharmacological approaches, medication when deemed appropriate, and effective after-care planning 1.

From the Research

Differentiation between Delirium and Dementia

The key differences between delirium and dementia are:

• Delirium is an acute confusional state characterized by inattention, cognitive dysfunction, and an altered level of consciousness 2, 3, 4, 5, 6
• Dementia is an insidious, chronic, and progressive loss of previously acquired cognitive ability 2, 3

Clinical Characteristics

Some clinical characteristics that distinguish delirium from dementia include:

• Onset: Delirium has a rapid onset, while dementia has a gradual onset 2, 3
• Duration: Delirium is typically short-term, while dementia is long-term 2, 3
• Level of consciousness: Delirium is characterized by an altered level of consciousness, while dementia is not 2, 3, 4
• Cognitive function: Delirium is associated with cognitive dysfunction, while dementia is associated with a decline in cognitive ability 2, 3, 4, 5, 6

Relationship between Delirium and Dementia

There is a complex relationship between delirium and dementia, with:

• Individuals with dementia being at higher risk for delirium 2, 3, 4, 5, 6
• Delirium being a risk factor for incident dementia 2, 3
• Delirium in individuals with dementia accelerating the underlying cognitive decline 2, 3