Acute disseminated encephalomyelitis in an elderly patient following pneumococcal vaccination with extremely high cerebrospinal fluid interleukin-6

Background

Postvaccination acute disseminated encephalomyelitis (ADEM) may develop 2–30 days after vaccination. However, ADEM following pneumococcal vaccination has never been reported.

Case presentation

We report a 73-year-old woman with ADEM following pneumococcal vaccination. She developed acute fever and consciousness disturbance 17 days after the second administration of 23-valent pneumococcal polysaccharide vaccine (PPSV23). Head magnetic resonance imaging (MRI) revealed numerous T2-high lesions, mainly involving the cerebral and cerebellar white matter and brainstem. Cerebrospinal fluid examination showed polymorphonuclear pleocytosis and markedly elevated interleukin-6 (58,400 pg/ml). Her symptoms and MRI lesions were promptly resolved by steroid pulse therapy, with no relapse.

Conclusion

Although PPSV23 is recommended for elderly individuals, this case highlights the risk of ADEM caused by unexpected immune activation following repeated administration of the vaccine.