When measles is not benign: meningoencephalitis and status epilepticus in an unvaccinated adolescent (case report).

Measles is a highly contagious viral exanthematous disease, caused by a Morbillivirus, that continues to cause outbreaks in under-immunized populations. While neurologic complications are rare, the progression to meningoencephalitis with convulsive status epilepticus is exceptional, particularly in immunocompetent adolescents. We report a 17-year-old unvaccinated male who presented with a febrile, descending asymptomatic maculopapular rash, lacking Koplik spots, followed by rapid onset of severe headache, photophobia, vomiting, and convulsive status epilepticus. Day-7 IgM was negative, and PCR was unavailable, prompting a broad viral, bacterial, and autoimmune workup, all of which were excluded. Cerebrospinal Fluid (CSF) showed mild protein elevation without pleocytosis, and repeat serology confirmed measles (IgM 1210 IU/mL; IgG 1980 IU/mL). The patient received meningeal-dose ceftriaxone, acyclovir, antiepileptics, and high-dose vitamin A per World Health Organization (WHO) recommendations, with complete neurologic recovery. This case highlights an uncommon but severe neurologic complication of measles in an unvaccinated adolescent, emphasizing the risk of diagnostic delay due to atypical features and early seronegativity. It reinforces the need for high clinical suspicion, broad etiologic evaluation, early empiric therapy, and sustained efforts to ensure complete vaccination.