American Board of Internal Medicine (ABIM) Certification Practice Exam

What does elevated 14-3-3 protein in the cerebrospinal fluid indicate?

1. Multiple sclerosis

2. Alzheimer's disease

3. Creutzfeldt-Jakob disease

4. Parkinson's disease

The correct answer is: Creutzfeldt-Jakob disease

The presence of elevated 14-3-3 protein in the cerebrospinal fluid (CSF) is particularly associated with Creutzfeldt-Jakob disease (CJD), a rapidly progressive neurodegenerative disorder caused by prion infection. 14-3-3 proteins are a family of regulatory proteins that have a role in various cellular processes, including the response to cellular stress and apoptosis. When neuronal injury occurs, these proteins can leak into the CSF, where they can be measured as a biomarker. In cases of CJD, the elevation of 14-3-3 protein is typically interpreted in conjunction with clinical findings and other diagnostic tests, as it may not be exclusive to this condition and can be seen in other forms of neurodegeneration. However, its significant levels are a strong signal that raises suspicion for CJD, and additional tests such as EEG or brain MRI might corroborate the diagnosis. In contrast, while multiple sclerosis, Alzheimer's disease, and Parkinson's disease may present with various neurological symptoms and changes in CSF composition, they are not specifically identified by elevated 14-3-3 protein. Thus, the elevation is a vital indicator predominantly associated with Creutzfeldt-Jakob disease in the context