What is the recommended lab workup for a young person presenting with perceived memory loss?

Recommended Laboratory Workup for Young Persons with Perceived Memory Loss

The recommended laboratory workup for a young person presenting with perceived memory loss should include complete blood count with differential, comprehensive metabolic panel, thyroid function tests, vitamin B12 and folate levels, inflammatory markers, and structural brain imaging, with additional specialized testing based on clinical presentation. 1

Initial Laboratory Assessment

• Complete blood count with differential to rule out anemia and other hematologic abnormalities 1
• Comprehensive metabolic panel including electrolytes, calcium, magnesium, and liver function tests 1
• Thyroid function tests (TSH, free T4) to identify thyroid dysfunction that can affect cognition 1, 2
• Vitamin B12, homocysteine, and folate levels to rule out deficiencies associated with cognitive impairment 1, 2
• Inflammatory markers (erythrocyte sedimentation rate and C-reactive protein) to identify inflammatory conditions 1
• Urinalysis and toxicology screen to identify potential metabolic or substance-related causes 2
• Serum or urine pregnancy test for all female patients 2

Neuroimaging

• Structural brain imaging with MRI (preferred) or CT scan if MRI is contraindicated 1, 3
• Neuroimaging is particularly important when there is:
  • Onset of cognitive symptoms within the past 2 years
  • Unexpected decline in cognition or function
  • Significant vascular risk factors 1, 3

Specialized Testing Based on Clinical Presentation

• Electrocardiogram to assess for cardiac abnormalities that may affect cerebral perfusion 2
• Cerebrospinal fluid (CSF) analysis should be considered in patients with:
  • Early-onset symptoms (under age 65)
  • Diagnostic uncertainty
  • Predominance of language, visuospatial, dysexecutive, or behavioral features 2
• HIV testing if risk factors are present 3
• Screening for depression and anxiety, which can manifest as or exacerbate cognitive symptoms 1

Advanced Biomarkers (for Specialized Settings)

• For patients seen in specialized memory clinics with persistent diagnostic uncertainty after initial workup:
  • [18F]-FDG PET scan can be considered for differential diagnosis purposes 2
  • Amyloid PET imaging may be considered in select cases, but should be ordered only by dementia experts 2
  • Blood-based biomarkers (BBMs) should only be used in specialist clinics and results confirmed with CSF or PET 2

Assessment of Non-Cognitive Markers

• Gait speed assessment (cut-off below 0.8m/s) as slower gait speed is associated with future dementia 2
• Dual-task gait testing in specialized memory clinics to help identify those at higher risk of progression 2
• Assessment for parkinsonism, which may increase odds of developing dementia 2
• Frailty assessment as a marker of future dementia risk 2

Important Considerations

• Corroborative history from a reliable informant is essential and more strongly predictive of cognitive impairment than subjective symptoms 4
• Medication review is crucial as certain medications (especially anticholinergics or sedative hypnotics) can contribute to cognitive symptoms 1
• Assessment of specific cognitive domains (memory, executive function, visuospatial abilities, language, personality/behavior) should be performed using standardized tools 1, 3

Common Pitfalls to Avoid

• Failing to obtain corroborative history from an informant 1
• Overlooking medical conditions that can influence biomarker interpretation 3
• Not considering age-specific etiologies - young-onset cognitive impairment has different common causes than late-onset 2
• Relying solely on patient self-report of memory problems without objective testing 4

Young patients with perceived memory loss require thorough evaluation as early diagnosis can identify potentially reversible causes and guide appropriate management strategies. The workup should be comprehensive but targeted based on clinical presentation and risk factors.