Bilateral functional hippocampectomy following recurrent bacterial meningitis: a case report

BACKGROUND: The hippocampal formation is indispensable to convert short-term into long-term memories. It is a brain region particularly vulnerable to a variety of noxious stimuli. Severe hippocampal injury with complete inability to convert short-term into long-term memories is very rare in bacterial meningitis. CASE PRESENTATION: At the age of 62 years, a white German female teacher acquired Listeria monocytogenes meningitis after the consumption of goat cheese manufactured from raw milk. Malabsorptive hydrocephalus required placement of a ventriculoperitoneal shunt. The further course became complicated by two shunt infections. Severe bilateral hippocampal atrophy developed. In spite of restoration of CSF drainage via a replacement shunt, the patient lost the capacity to form new memories. Conversely, her personality and the ability to work with previously stored information remained intact for many years. CONCLUSIONS: Protection of the hippocampal formation and preservation of the capacity to form new memories is a major goal in the treatment of bacterial meningitis. Further improvement of outcome in bacterial meningitis will depend on approaches that effectively protect the hippocampal formation.