What are the key differences in diagnosis and treatment between delirium and dementia?

Differentiating Delirium from Dementia: Diagnosis and Management

Delirium is an acute confusional state with disturbed consciousness, cognitive dysfunction, and fluctuating course that develops rapidly over hours to days, while dementia is a chronic, progressive neurocognitive disorder with insidious onset over months to years. 1

Key Diagnostic Differences

Feature	Delirium	Dementia
Onset	Acute (hours to days)	Insidious (months to years)
Course	Fluctuating	Stable, gradually progressive
Attention	Severely impaired	Generally preserved until late stages
Consciousness	Altered	Clear until late stages
Reversibility	Often reversible with treatment	Generally irreversible
Hallucinations	Common	Less common (except in certain types)
Sleep-wake cycle	Disturbed	Usually preserved until late stages

Diagnostic Approach for Delirium

1. Use validated assessment tools:

   • Confusion Assessment Method (CAM) is the most widely used diagnostic instrument 1
   • Intensive Care Delirium Screening Checklist (ICDSC) for critically ill patients 1

2. Look for cardinal features:

   • Disturbed level of consciousness
   • Acute change in cognition
   • Perceptual disturbances
   • Fluctuating course throughout the day (often worse in evening - "sundowning") 1

3. Identify delirium subtype:

   • Hyperactive: agitation, restlessness, attempting to remove medical devices
   • Hypoactive: lethargy, reduced awareness, apathy (often underdiagnosed)
   • Mixed: features of both 1

4. Investigate underlying causes:

   • Laboratory investigations (CBC, metabolic panel, thyroid function)
   • Medication review (especially steroids, anticholinergics, opioids)
   • Assessment for infection, metabolic disorders, or organ failure 1

Diagnostic Approach for Dementia

1. Establish gradual cognitive decline over time
2. Document impairment in multiple cognitive domains
3. Rule out delirium and other causes of cognitive impairment
4. Assess functional impact on activities of daily living

Management Differences

Delirium Management

1. Non-pharmacological interventions (first-line):

   • Environmental modifications (reduce noise, provide orientation cues)
   • Cognitive support (frequent reorientation, orientation boards)
   • Sensory optimization (ensure glasses and hearing aids are available)
   • Early mobilization
   • Sleep-wake cycle regulation 1

2. Address underlying causes:

   • Identify and discontinue delirium-inducing medications
   • Treat infections, metabolic disturbances, or other medical conditions
   • Manage pain effectively 2, 1

3. Pharmacological management (for severe symptoms only):

   • For moderate symptoms: oral haloperidol, risperidone, olanzapine, or quetiapine
   • For severe agitation: haloperidol, olanzapine, or chlorpromazine
   • Benzodiazepines only for refractory agitation or alcohol withdrawal 1

4. Specific interventions:

   • Encourage mobilization after surgery
   • Address pain using both verbal and non-verbal assessment
   • Review medications, especially in polypharmacy
   • Address poor nutrition and sensory impairments 2

Dementia Management

1. Long-term cognitive support
2. Cholinesterase inhibitors and/or memantine
3. Management of behavioral symptoms
4. Caregiver education and support
5. Advance care planning

Special Consideration: Delirium Superimposed on Dementia (DSD)

DSD is a common but often undetected problem that significantly reduces quality of life in patients with dementia 3. It presents unique diagnostic challenges:

• Requires knowledge of patient's baseline cognitive status
• Look for acute changes in attention, alertness, and motor function
• Informant history is crucial to identify acute changes 4

Management of DSD:

1. Prevention is critical - implement multicomponent interventions
2. Identify and treat underlying precipitants
3. Create an optimal environment for brain recovery
4. Involve family members/caregivers who can recognize changes from baseline 4

Common Pitfalls and Caveats

1. Hypoactive delirium is frequently missed but is the most prevalent subtype in palliative care 1

2. Medication-induced delirium is usually reversible, while delirium due to hypoxic encephalopathy or organ failure is often irreversible 1

3. Avoid assuming cognitive impairment in elderly patients is always dementia - always consider delirium first as it is potentially reversible

4. Polypharmacy is a significant risk factor - always perform a medication review 2

5. Pain can be a risk factor for delirium but is difficult to detect in persons with dementia 2

6. Delirium may highlight vulnerability to developing dementia - follow-up cognitive assessment after resolution is important 5

7. Untreated DSD leads to worse outcomes including higher rates of mortality and institutionalization compared to either condition alone 4