Difference Between Delirium and Dementia

Key Difference – Delirium vs Dementia
 

Dementia and delirium are often seen among elderly people, and these diseases are responsible for the deterioration of cognitive functions in the affected group of patients. Delirium, also known as acute organic psychosis or toxic confusional state, is an acute or subacute brain failure in which the impairment of attention is accompanied by abnormalities in mood and perception. Dementia, on the other hand, is a clinical syndrome which is defined by the presence of acquired loss of higher mental functions, sufficient severity to cause social or occupational impairment and the occurrence in clear consciousness. The main difference between delirium and dementia is that in dementia, there are no alterations in the level of consciousness while in delirium, the consciousness is impaired.

CONTENTS

1. Overview and Key Difference
2. What is Delirium
3. What is Dementia
4. Similarities Between Delirium and Dementia
5. Side by Side Comparison – Delirium vs Dementia in Tabular Form
6. Summary

What is Delirium?

Delirium, which is also known as acute organic psychosis or toxic confusional state, is an acute or subacute brain failure in which the impairment of attention is accompanied by abnormalities in mood and perception.

Predisposing Factors for Delirium

• Extremes of age
• Brain damage
• Dislocation to an unfamiliar environment
• Sleep deprivation
• Sensory extremes
• Immobilization
• Visual and hearing impairment

Causes of Delirium

• Systemic infections
• Metabolic disturbances in conditions such as heart failure, renal failure, and liver failure
• Vitamin B12 and thiamine deficiency
• Hypothyroidism and Cushing’s syndrome
• Epilepsy and space-occupying lesions in the cranial cavity
• Adverse effects of drugs such as anticonvulsants and antimuscarinic agents
• Drug and alcohol withdrawal

Diagnostic Criteria

• Disturbance of consciousness
• Change in cognition
• Development of the symptoms over a short period of time (hours to days)
• Fluctuation over the course of day

Management

A proper history can reveal the underlying cause. The patient should be treated in a place that does not allow exits. The nutritional status of the patient must be improved. Any current medications that the patient is on should be thoroughly reviewed. Haloperidol has been proven to be effective in the management of severe delirium. The use of benzodiazepine is not advocated because it can prolong the period of confusion.

What is Dementia?

Dementia is a clinical syndrome which is defined by the following criteria:

• Acquired loss of higher mental functions
• Sufficient severity to cause social or occupational impairment
• Occurring in clear consciousness

Dementia is most often an irreversible, progressive condition.

Causes of Dementia

• Degenerative brain conditions such as Alzheimer’s disease
• Vascular Lesions
• Metabolic causes such as uremia
• Toxicity of heavy metals and alcohol
• Vitamin B12 and thiamine deficiency
• Trauma
• Infections such as HIV
• Hypothyroidism and hypoparathyroidism
• Psychiatric illnesses

Clinical Assessment

A clear and descriptive history should be carefully taken right at the beginning. The patient may not divulge all the relevant information mostly due to the social stigma associated with conditions like this. The mini-mental state examination and Addenbrooke’s Cognitive examination are the tools that can be used to assess the mental health status of the patient.

Investigations

1. Blood Tests

• FBC, ESR, vitamin B12
• Urea and electrolytes
• Glucose
• Liver biochemistry
• Serum calcium
• Thyroid functions
• HIV serology

2. Imaging

• CT or MRI brain scan

3. Occasionally brain biopsies and genetic studies

Management

In most cases, the exact cause of dementia is not identified. Therefore, only supportive management that is aimed at preserving the dignity of the patient is provided. Pharmacological agents such as cognitive enhancers, cholinesterase inhibitors, and memantine are often prescribed, but their effect in modifying the disease progression remains controversial. Since there is a strong association between dementia and depression, antidepressants should be given when depression is suspected.

What are the Similarities Between Delirium and Dementia?

• Both conditions are associated with an impairment in the cognitive functions.
• Elderly people are more likely to be affected by dementia and delirium.

What is the Difference Between Delirium and Dementia?

Summary – Delirium vs Dementia

Delirium, which is also known as acute organic psychosis or toxic confusional state, is an acute or subacute brain failure in which the impairment of attention is accompanied by abnormalities in mood and perception. A diagnosis of dementia is made by observing acquired loss of higher mental functions, sufficient severity to cause social or occupational impairment, and occurring in clear consciousness. Unlike in dementia where there is no change in the patient’s level of consciousness, in delirium, the consciousness is impaired. This is the major difference between delirium and dementia.

Reference:

1.Kumar, Parveen J., and Michael L. Clark. Kumar & Clark clinical medicine. Edinburgh: W.B. Saunders, 2009.

Image Courtesy:

1. “Delirium” by Erich Ferdinand (CC BY 2.0) via Flickr
2. “63612” (Public Domain) via Pixabay