Delirium

Introduction to Delirium in the Canadian Healthcare Context

Delirium is a common and serious neuropsychiatric syndrome that presents a significant challenge in Canadian healthcare settings. As a medical student preparing for the MCCQE1, understanding delirium is crucial for your success in the exam and future practice in the Canadian healthcare system.

Definition and Epidemiology

Delirium is defined as an acute, fluctuating disturbance in attention, awareness, and cognition that is not better explained by a pre-existing neurocognitive disorder.

Canadian Epidemiology

• Prevalence in Canadian hospitals: 10-31% of admitted patients
• Incidence in ICUs: Up to 80% of mechanically ventilated patients
• Elderly patients (>65 years): 30-40% develop delirium during hospitalization

Pathophysiology

The exact pathophysiology of delirium is not fully understood, but several mechanisms are thought to contribute:

1. Neurotransmitter imbalances (especially acetylcholine and dopamine)
2. Neuroinflammation
3. Oxidative stress
4. Disruption of the sleep-wake cycle
5. Alterations in cerebral blood flow and metabolism

Risk Factors

Understanding risk factors is crucial for identifying high-risk patients and implementing preventive strategies in Canadian healthcare settings.

Clinical Presentation and Diagnosis

Recognizing the clinical features of delirium is essential for prompt diagnosis and management in Canadian healthcare settings.

Key Features

1. Acute onset and fluctuating course
2. Inattention
3. Disorganized thinking
4. Altered level of consciousness

Subtypes of Delirium

1. Hyperactive: Agitation, restlessness, hallucinations
2. Hypoactive: Lethargy, decreased responsiveness
3. Mixed: Fluctuation between hyperactive and hypoactive states

Diagnostic Criteria (DSM-5)

A. Disturbance in attention and awareness B. Acute onset and fluctuating course C. Additional cognitive disturbance D. Not better explained by another neurocognitive disorder E. Evidence of an underlying cause

Diagnostic Tools

• Confusion Assessment Method (CAM): Widely used in Canadian hospitals
• 4AT: Rapid assessment tool for delirium and cognitive impairment
• Richmond Agitation-Sedation Scale (RASS): Used in ICU settings

Management of Delirium in Canadian Healthcare

Management of delirium in Canada focuses on a multicomponent approach, emphasizing prevention and non-pharmacological interventions.

Canadian Guidelines for Delirium Management

The Canadian Coalition for Seniors' Mental Health (CCSMH) has published guidelines for the assessment and treatment of delirium in older adults. Key recommendations include:

1. Routine screening for delirium in high-risk patients
2. Use of validated assessment tools (e.g., CAM)
3. Implementation of multicomponent non-pharmacological interventions
4. Judicious use of antipsychotics, with close monitoring for adverse effects
5. Education of healthcare providers and family members about delirium prevention and management

Key Points to Remember for MCCQE1

• Delirium is common in Canadian hospitals, especially among elderly patients
• Understand the risk factors specific to the Canadian population
• Know the diagnostic criteria and commonly used assessment tools in Canada
• Emphasize non-pharmacological management strategies
• Be familiar with Canadian guidelines for delirium management
• Recognize the importance of delirium prevention in Canadian healthcare settings

Sample MCCQE1-Style Question

# Sample Question

An 82-year-old woman is admitted to a Canadian hospital for management of a urinary tract infection. On the second day of admission, the nurse reports that the patient has become confused and agitated. The patient was oriented and calm yesterday. Which one of the following is the most appropriate next step in management?

- [ ] A. Administer intravenous haloperidol
- [ ] B. Order a CT scan of the head
- [ ] C. Perform a Confusion Assessment Method (CAM) evaluation
- [ ] D. Prescribe oral lorazepam
- [ ] E. Restrain the patient for her safety

Explanation

The correct answer is:

• C. Perform a Confusion Assessment Method (CAM) evaluation

Explanation: In this scenario, the patient is showing signs suggestive of delirium (acute onset of confusion and agitation). The most appropriate next step is to perform a structured assessment using a validated tool such as the Confusion Assessment Method (CAM). This aligns with Canadian guidelines for delirium management, which recommend routine screening and use of validated assessment tools.

Option A (haloperidol) is incorrect as pharmacological management should not be the first-line approach. Option B (CT scan) may be considered later but is not the most appropriate initial step. Option D (lorazepam) is incorrect as benzodiazepines can worsen delirium and should be avoided except in specific situations like alcohol withdrawal. Option E (restraints) is not recommended as it can exacerbate delirium and should be used only as a last resort.

References

1. Canadian Coalition for Seniors' Mental Health. (2014). The Assessment and Treatment of Delirium. Toronto: CCSMH.

2. Inouye, S. K., Westendorp, R. G., & Saczynski, J. S. (2014). Delirium in elderly people. The Lancet, 383(9920), 911-922.

3. Bush, S. H., Marchington, K. L., Agar, M., Davis, D. H., Sikora, L., & Tsang, T. W. (2017). Quality of clinical practice guidelines in delirium: a systematic appraisal. BMJ Open, 7(3), e013809.

4. Michaud, L., Büla, C., Berney, A., Camus, V., Voellinger, R., Stiefel, F., & Burnand, B. (2007). Delirium: Guidelines for general hospitals. Journal of Psychosomatic Research, 62(3), 371-383.

5. Canadian Patient Safety Institute. (2016). Hospital Harm Improvement Resource: Delirium. Retrieved from CPSI website (opens in a new tab)