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This is a clinician-written, evidence-based guide aligned to the MCC Examination Objectives. It is structured by clinical presentation — the way the MCCQE tests and the way patients actually present. Management reflects current Canadian guidelines (CMA, CFPC, CPS). Always cross-reference with institutional protocols and clinical judgment.
Key points
- First exclude delirium: acute fluctuation and inattention are not dementia.
- Collateral history is essential to establish decline, function, safety, driving, finances, medication management and caregiver strain.
- Screen reversible contributors: medications, depression, alcohol, sleep apnoea, hypothyroidism, B12 deficiency, normal-pressure hydrocephalus and subdural haematoma.
- Alzheimer disease is common, but vascular, Lewy body, frontotemporal and Parkinson disease dementia have distinctive patterns.
- Canadian preventive guidance recommends against instrument-based screening of asymptomatic older adults, but symptomatic patients require assessment.
Approach to the Presentation
Assess time course, affected cognitive domains, functional impairment and safety. Use MoCA or MMSE as a tool, not a diagnosis. Examine gait, parkinsonism, focal deficits, mood, vision/hearing and medication burden. Involve family/caregivers early.
Differential Diagnosis
| diagnosis | likelihood | key features | distinguishing test |
|---|---|---|---|
| Delirium | must-not-miss | Acute fluctuating attention impairment, altered consciousness, medical trigger | CAM and medical workup |
| Depression/pseudodementia | common | Low mood, anhedonia, sleep/appetite change, prominent subjective memory complaints | PHQ-9/clinical interview; cognitive improvement with treatment |
| Alzheimer disease | common | Insidious episodic memory loss then language/executive deficits; preserved motor early | Clinical criteria, cognitive testing, exclusion of reversible causes |
| Vascular cognitive impairment | common | Stepwise or executive dysfunction, gait changes, stroke risk factors | MRI/CT showing vascular disease |
| Medication/substance cognitive impairment | common | Anticholinergics, benzodiazepines, opioids, cannabis/alcohol, polypharmacy | Medication review and deprescribing trial |
| Lewy body dementia | less common | Fluctuating cognition, visual hallucinations, REM sleep behaviour disorder, parkinsonism, antipsychotic sensitivity | Clinical pattern |
| Frontotemporal dementia | less common | Early behaviour/personality or language change, younger onset | Neuropsychology, MRI frontal/temporal atrophy |
| Normal-pressure hydrocephalus | less common | Gait apraxia, urinary symptoms, cognitive decline | MRI/CT ventriculomegaly; specialist CSF tap test |
| B12/thyroid/neurosyphilis/HIV | less common | Reversible or treatable contributors depending on risk factors | B12, TSH, CBC; HIV/syphilis if indicated |
Red Flags & Key History
Symptoms
Acute change or fluctuation
Rapidly progressive dementia over weeks-months
New focal deficit, seizure or headache
Unsafe driving, wandering, medication errors or financial vulnerability
Gradual decline over years
Signs
Inattention or reduced consciousness
Parkinsonism, hallucinations or gait apraxia
Focal neurological signs
Poor vision/hearing confounding testing
Approach to Investigation
First-line
Collateral history + functional assessmentEssential for diagnosis and safety.
MoCA or MMSEQuantifies cognitive domains; interpret with education/language context.
CBC, electrolytes, calcium, creatinine, liver enzymes, TSH, B12Baseline reversible-cause screen.
Second-line
CT or MRI brainYoung onset, rapid progression, focal signs, gait disorder, anticoagulation/trauma, atypical features or to support subtype.
Depression, sleep and medication assessmentCommon reversible contributors.
HIV/syphilis testingWhen risk factors or atypical presentation.
Specialist
Memory clinic/geriatrics/neurologyYoung onset, rapid progression, atypical features, diagnostic uncertainty or complex safety planning.
Management Principles
MCC Neurocognitive Disorders objective + Canadian Task Force cognitive impairment guidance1
Initial management
- Treat delirium, depression, sleep disorder and reversible metabolic causes
- Deprescribe anticholinergics/sedatives where possible
- Assess driving, finances, cooking, medication management and caregiver support
2
Dementia care
- Discuss diagnosis, prognosis, advance care planning and substitute decision-making
- Consider cholinesterase inhibitor for Alzheimer, Parkinson or Lewy body dementia when appropriate
- Connect to community supports and caregiver resources
3
Risk reduction
- Exercise, vascular risk management, hearing/vision optimization, social engagement and medication review
Complications & Pitfalls
- Screening asymptomatic people: Canadian guidance recommends against instrument-based screening in asymptomatic older adults.
- Missing delirium: acute inattention is not dementia.
- Ignoring caregiver history: function and safety often come from collateral sources.
- Overusing antipsychotics: especially dangerous in Lewy body dementia.
MCCQE1 Exam Tips
- 1Dementia has stable consciousness; delirium fluctuates.
- 2Collateral history is not optional.
- 3NPH triad: gait first, urinary symptoms, cognitive decline.
- 4Lewy body dementia: visual hallucinations + parkinsonism + fluctuations.
- 5Depression can mimic cognitive decline and is treatable.
- 6MoCA/MMSE supports assessment but does not replace clinical diagnosis.
Put your reading into practice
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