Evaluation of Organic Causes in Dementia

Initial Laboratory Tests (Tier 1)

The American Geriatrics Society recommends a basic panel including complete blood count, electrolytes, glucose, calcium, thyroid function, vitamin B12, liver and kidney function as first-line tests, complemented with brain neuroimaging (preferably non-contrast MRI or CT scan if MRI is not available) 1, 2, 3
The initial laboratory tests should include a complete metabolic panel that comprises electrolytes (sodium, potassium) 1, 2, 3
Glucose levels should be assessed as part of the initial evaluation 1, 2, 3
Calcium levels should be evaluated in the initial assessment 1, 2, 3
Renal function (BUN, creatinine) should be assessed 2, 3
Liver function should be evaluated 2, 3
Thyroid function (TSH) should be assessed 1, 2, 3
Vitamin B12 levels should be evaluated 1, 2, 3
Homocysteine levels may be considered for evaluation 4

The American College of Radiology recommends non-contrast brain MRI (or CT scan if MRI is not available) as the first-line neuroimaging test 4, 5
Neuroimaging is crucial for evaluating patterns of atrophy (hippocampal and cortical) 4, 6
Lesions such as infarcts and leucoaraiosis should be assessed through neuroimaging 4, 5
Non-degenerative conditions (hydrocephalus, space-occupying lesions) should be evaluated through neuroimaging 4, 6

In cases with atypical presentations, serology for syphilis (RPR, FTA-ABS) may be considered 2, 3, 4
Serology for HIV may be considered in certain cases 4, 7
Lipid profile may be evaluated in patients with suspected dementia 4, 8
Erythrocyte sedimentation rate (ESR) may be considered in the evaluation 4, 7
C-reactive protein (CRP) may be evaluated in certain cases 4, 9
Antithyroid antibodies (anti-TPO, anti-thyroglobulin) may be considered to rule out Hashimoto's encephalopathy 4, 7
HbA1c may be evaluated in patients with suspected diabetes 4, 7

For complex cases, early onset (<65 years), or rapidly progressive dementia, lumbar puncture with CSF analysis may be considered 4, 7
Advanced neuroimaging studies, including PET scans with FDG (or SPECT) and amyloid PET, may be considered in complex cases 4, 5, 10

In patients with Down syndrome, special attention should be given to hypothyroidism, which is more prevalent 1
In cases of rapid cognitive decline, a broader panel including tests for autoimmune, paraneoplastic, or infectious diseases should be considered 10, 5

In patients presenting with new‑onset memory loss, hypoglycemia and hyponatremia are the most common metabolic disturbances that are often missed; timely identification and correction can completely reverse the cognitive impairment 11 (Evidence level: observational study).