An 88-year-old presents with dementia; which reversible condition should be checked?

• A. A brain biopsy is recommended to determine a therapeutic plan.
• B. Thyroid function testing is used to rule out a reversible cause of dementia.
• C. Hyperreflexia and sensory loss occur early in Alzheimer's disease.
• D. A CT scan is the gold standard to confirm the diagnosis.

Answer: (B)

Screening for reversible contributors to cognitive decline is essential in an elderly patient with dementia. Thyroid dysfunction, especially hypothyroidism, can cause cognitive impairment that mimics dementia and is treatable. Checking thyroid function with TSH and free T4 helps identify this reversible factor, and treatment with thyroid hormone can improve or even reverse cognitive symptoms in some cases.

Brain biopsy is invasive and not indicated for dementia workup. A CT scan can help rule out other brain issues but is not the standard test to confirm dementia itself. Hyperreflexia and sensory loss are not typical early features of Alzheimer's disease, so that pattern does not point to the most reversible cause.