Histopathology of bacterial meningitis Snapshots of the brain

Bacterial meningitis shows histopathological characteristics that are specific to each causative agent. Identifying these specific characteristics is important because it adds to the knowledge about the pathophysiology of tissue damage by the various causative agents. This could possibly lead to the development of new, more effective treatments.
We studied 31 cases of pneumococcal meningitis and the specific histopathological characteristics were described, namely: inflammation of the medium and large arteries, intraparenchymal bleeding, cerebritis, thrombosis, and infarctions. Of these characteristics, inflammation of medium and large arteries is not only practically universally present, but is also clearly associated with thrombosis and infarctions. This suggests that vascular damage plays a key role in the pathophysiology of brain damage in pneumococcal meningitis.
The study of 4 autopsy cases of pneumococcal meningitis with catastrophic cebrovascular complications after initially successful recovery showed that its etiology is multifactorial with vascular inflammation, thromboembolism in the large arteries and infectious intracranial aneurysms. The observation that Streptococcus pneumoniae could be detected intra- and extracellularly (individually or in groups) in patients treated with antibiotics (up to 35 days in length) is striking.
We studied the histopathological characteristics of listeria meningitis with the same methodology and the observations show that Listeria monocytogenes penetrates further into the CNS via the ventricles and spreads through the perivascular spaces and thus forms abscesses. Extensive efferocytosis observed is believed to be used by L. monocytogenes for cell-to-cell spread.
Furthermore, we studied animal models of bacterial meningitis to determine if these mimic meningitis in humans.