From the Guidelines
For a patient with dementia experiencing increased confusion, I recommend ordering a comprehensive set of routine Tier 1 laboratory studies, including a comprehensive metabolic panel (CMP), complete blood count (CBC), urinalysis, thyroid function tests (TSH, free T4), vitamin B12 and folate levels, and a urine toxicology screen, as these tests are essential in identifying common reversible causes of worsened confusion in dementia patients, as suggested by the Alzheimer's Association clinical practice guideline 1. When evaluating a patient with dementia and increased confusion, it is crucial to consider the patient's medical risks and profile, and to obtain laboratory tests in a multi-tiered and individualized approach, as recommended by the Alzheimer's Association clinical practice guideline 1. Some key laboratory tests to consider ordering include:
- Comprehensive metabolic panel (CMP) to evaluate for metabolic disturbances
- Complete blood count (CBC) to evaluate for infections or other hematologic abnormalities
- Urinalysis to evaluate for urinary tract infections or other renal abnormalities
- Thyroid function tests (TSH, free T4) to evaluate for thyroid dysfunction
- Vitamin B12 and folate levels to evaluate for nutritional deficiencies
- Urine toxicology screen to evaluate for substance use or toxicity Additionally, consider ordering blood glucose, electrolytes (particularly sodium, calcium, and magnesium), blood urea nitrogen (BUN), creatinine, liver function tests, ammonia levels, and arterial blood gases if indicated, as these tests can help identify underlying causes of confusion, such as metabolic disturbances, medication effects, dehydration, and organ dysfunction, as suggested by the guideline 1. In selected cases, consider ordering medication levels (especially for anticonvulsants or digoxin), HIV testing, RPR/VDRL for syphilis, and inflammatory markers like ESR and CRP, as these tests can help identify underlying causes of confusion, such as infections, medication effects, or inflammatory conditions, and prompt identification and treatment of these underlying causes can significantly improve the patient's cognitive status and prevent further decline, as recommended by the guideline 1.
From the Research
Laboratory Tests for Dementia
When evaluating a patient with dementia and increased confusion, the following laboratory tests are recommended:
- Complete blood count and electrolyte, glucose, calcium, and thyroid levels, as suggested by the Canadian Consensus Conference on the Assessment of Dementia (CCCAD) guidelines 2
- B12 levels, computed tomography scan of the head, and testing for syphilis, which should be considered when the clinical situation warrants 2
- Basic metabolic panel, including electrolytes such as potassium and chloride, as well as blood urea nitrogen and creatinine, to assess renal function and acid-base homeostasis 3
Diagnostic Evaluation
A comprehensive evaluation for dementia includes:
- A thorough medical history and physical examination to identify potential underlying causes of cognitive decline 4, 5
- Validated cognitive assessment tools to identify the extent and nature of cognitive deficits and track disease progression over time 4
- Brain imaging studies to help identify any contributing factors 4, 5
- Laboratory tests, such as those mentioned above, to identify specific causes contributing to memory loss 5
Approach to Investigations
The approach to investigations should be selective, using clinical judgment to order laboratory tests, as the prevalence of reversible dementias is likely lower than previously believed 2. A patient-centered, multidisciplinary team approach, including nonpharmacological and pharmacologic treatments, should be used to guide care 5.