From the Guidelines
A secondary dementia workup should include a comprehensive diagnostic assessment, starting with an expanded history, neurologic physical examination, and general labs, as well as structural brain imaging with MRI, as recommended by the most recent guidelines 1. When evaluating a patient with suspected dementia, it is essential to prioritize a thorough diagnostic workup to identify potentially reversible causes of cognitive impairment. The diagnostic process should begin with:
- Obtaining an expanded history focused on cognitive abilities, including onset of complaint, pace of decline, and nature of cognitive loss, such as short-term memory and instrumental ADLs 1
- Conducting a neurologic physical examination to assess for any neurological abnormalities
- Assessing risk factors for cognitive decline, such as cerebrovascular risk factors, and medications that may contribute to cognitive impairment, like anticholinergics or sedative hypnotics 1
- Evaluating for psychiatric conditions that may mimic or contribute to dementia symptoms The laboratory testing should include:
- General labs, such as thyroid function tests, vitamin B12, homocysteine, complete blood count with differential, complete metabolic panel, erythrocyte sedimentation rate, and C-reactive protein 1
- Structural brain imaging with MRI, or head CT if MRI is contraindicated, to detect vascular changes, atrophy patterns, and structural abnormalities 1 By following this comprehensive approach, clinicians can increase the chances of identifying reversible causes of dementia and providing appropriate treatment to improve patient outcomes.
From the Research
Secondary Dementia Workup
- A thorough diagnostic evaluation for dementia involves a clinical history, physical examination, and brief cognitive testing 2, 3, 4, 5.
- Laboratory tests, such as complete blood count and electrolyte, glucose, calcium, and thyroid levels, are recommended as part of the core investigations 3, 4.
- Structural imaging with computed tomography or magnetic resonance imaging is recommended in selected cases to rule out treatable causes of dementia or to rule in cerebrovascular disease 2, 3.
- Neuropsychological testing and measurement of biomarkers may be considered in atypical dementia cases, such as age of onset younger than 65 years, rapid symptom onset, and/or impairment in multiple cognitive domains but not episodic memory 2.
- Vitamin B12 deficiency is a potentially reversible cause of dementia, and replacement therapy may improve cognitive outcomes in deficient patients 6.
Diagnostic Approaches
- Clinical criteria for diagnosing most forms of dementia are available, and a standard diagnostic evaluation can be performed by family physicians over multiple visits 3.
- A list of core laboratory tests is recommended, including complete blood count and electrolyte, glucose, calcium, and thyroid levels 3, 4.
- Structural neuroimaging is advised in selected cases, while functional neuroimaging, neuropsychological testing, and measurement of biomarkers have shown promise but are not yet recommended for routine use by family physicians 3.
Laboratory Evaluation
- The Canadian Consensus Conference on the Assessment of Dementia (CCCAD) guidelines recommend core investigations, including complete blood count and electrolyte, glucose, calcium, and thyroid levels 4.
- Tests to be done "when the clinical situation warrants" include B12 levels, computed tomography scan of the head, and testing for syphilis 4.
- Prospective cohort studies suggest the use of clinical judgment in ordering laboratory investigations, and the prevalence of reversible dementias is likely lower than previously believed 4.