TABLE 7-3.
Recommended Initial Screening Tests for Evaluation of a Rapidly Progressive Dementia
| Category | Initial Screen | Secondary Tier (Depending on Initial Screen and Clinical Scenario) |
|---|---|---|
| Blood tests | Complete blood cell count with differential | Cancer screen (eg, serum protein electrophoresis, serum immunoelectrophoresis, cancer antigen 125) |
| Basic metabolic panel (including calcium, magnesium, phosphorus) |
Blood smear | |
| Liver function tests | Coagulation profile | |
| Rapid plasma reagin (RPR) | Hypercoagulability testing | |
| Rheumatologic screen (erythrocyte sedimentation rate, antinuclear antibody, and C-reactive protein) |
Homocysteine | |
| Methylmalonic acid | ||
| Thyroid function tests (thyroid-stimulating hormone [TSH], free thyroxine) |
Additional rheumatologic tests (eg, cytoplasmic antineutrophil cytoplasmic antibody, perinuclear antineutrophil cytoplasmic antibody, double-stranded DNA, Smith antigen-ribonucleoprotein, SCL-70, SSA/SSB, rheumatoid factor, C3, C4, CH50) |
|
| Vitamin B12 | ||
| Human immunodeficiency virus | ||
| Medication levels as clinically indicated (eg, lithium, phenytoin) |
Antithyroglobulin and antithyroperoxidase antibodies |
|
| Lyme antibodies | ||
| Paraneoplastic/autoimmune antibodies | ||
| Additional endocrinologic tests (eg, cortisol) | ||
| Lymphoma markers15 | ||
| Urine | Urine analysis (with or without culture) | Urine culture |
| Urine toxicology screen (if indicated) | Heavy metal screen (24 hours) | |
| CSF | Cell count and differential | Whipple PCR |
| Protein | Metagenomic deep sequencing (CSF, biopsy tissue) | |
| Glucose | Phosphorylated tau, amyloid-β42 | |
| IgG index | CSF β2-microglobulin and Epstein-Barr virus PCR (lymphoma) |
|
| Oligoclonal bands | ||
| Venereal Disease Research Laboratory (VDRL) | ||
| 14-3-3 protein western blot | ||
| Total tau enzyme-linked immunosorbent assay (ELISA) |
||
| Neuron specific enolase ELISA | ||
| Real-time quaking induced conversion (RT-QuIC) test |
||
| Cryptococcal antigena | ||
| Viral polymerase chain reactions (PCRs), antibodies, and culturesb |
||
| Bacterial, fungal, acid-fast bacilli stains, and culturesc |
||
| Cytologyd | ||
| Flow cytometryd | ||
| Imaging | Brain MRI (including T1, T2, fluid-attenuated inversion recovery [FLAIR], diffusion-weighted imaging, apparent diffusion coefficient map, hemosiderin sequence) with and without contrast |
CT head |
| CT chest, abdomen, and pelvis with and without contrast | ||
| Magnetic resonance angiography/magnetic resonance venography | ||
| Chest x-ray (if clinically indicated) | Computed tomography angiography/brain angiogram |
|
| Magnetic resonance spectroscopy (for lesions or masses) |
||
| Mammogram | ||
| Body fluorodeoxyglucose positron emission tomography (FDG-PET)/CT scan |
||
| Testicular or pelvic ultrasound | ||
| Carotid ultrasound | ||
| Echocardiogram | ||
| Other tests | EEG | Electromyogram/nerve conduction study |
| Ophthalmologic examination or vitreous sampling (eg, for lymphoma) |
||
| Brain biopsy with or without meningeal biopsy (especially if above tests are nondiagnostic) |
||
CSF = cerebrospinal fluid; CT = computed tomography; DNA = deoxyribonucleic acid; EEG = electroencephalogram; IgG = immunoglobulin G; MRI = magnetic resonance imaging; SSA = Sjögren syndrome A; SSB = Sjögren syndrome B.
Initial screening for cryptococcal antigen depends on the clinical scenario and the geographic location.
Initial screening for viral PCRs, antibodies, and cultures depends on the clinical scenario, MRI findings, geographic location, and patient’s travel history.
Initial screening for bacterial, fungal, acid-fast bacilli stains, and cultures depends on the clinical scenario and imaging findings.
Initial screening for cytology and flow cytometry depends on the clinical scenario, MRI findings, if cancer is suspected, or if CSF pleocytosis is present.