A 9-year-old boy presents with 6 months of progressive personality change, declining school performance, and frequent myoclonic jerks. He had uncomplicated measles at age 2 years. EEG shows periodic burst-suppression complexes. Which finding will confirm the diagnosis?

• A Rise in heterophile antibody titers
• B Isolation of measles virus by culture from throat swab
• C Detection of oligoclonal bands restricted to serum
• D Detection of high-titer anti-measles IgG antibodies in the cerebrospinal fluid ✓

Explanation

Subacute sclerosing panencephalitis is a rare late complication of measles caused by a defective, non-productive viral infection of neurons, appearing years after the initial illness. The hallmark diagnostic test is demonstration of markedly elevated anti-measles antibodies in the CSF, since intrathecal synthesis cannot be explained by serum transfer. Live virus is never recoverable from secretions at this stage, and heterophile antibodies relate to Epstein-Barr virus, not measles.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.