In a patient with rapidly progressive dementia and typical EEG changes suggestive of Creutzfeldt-Jakob disease, which CSF finding provides supportive laboratory evidence of the diagnosis?
- A Reduced Aβ42 with elevated tau
- B Oligoclonal bands with raised IgG index
- C Elevated 14-3-3 protein ✓
- D Positive cryptococcal antigen
Correct answer: C. Elevated 14-3-3 protein
Explanation
Detection of 14-3-3 protein in CSF supports a diagnosis of sporadic Creutzfeldt-Jakob disease when combined with a compatible clinical picture and EEG showing periodic sharp wave complexes, reflecting rapid neuronal destruction. Oligoclonal bands point toward multiple sclerosis, the reduced Cβ42 with raised tau pattern is the Alzheimer signature, and cryptococcal antigen diagnoses fungal meningitis in the immunosuppressed. None of these fit a prion disease.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.