Meningitis

Excerpt

Meningitis is a broad term encompassing many causes of meningeal irritation and inflammation, both infectious and non-infectious. It describes inflammation of the meningeal layers of the brain and is most often associated with bacteria or viruses. While meningitis can be a life-threatening disorder, particularly bacterial meningitis, other entities can cause meningeal irritation, eg, viruses, systemic inflammatory disorders, certain medications, and even vaccinations, some with good outcomes. Before the era of antibiotics, bacterial meningitis was universally fatal. Nevertheless, even with innovations in diagnosis and treatment, bacterial meningitis can still carry a mortality rate of 25% or greater, particularly in low-income countries. Signs and symptoms of meningeal inflammation have been recorded in countless ancient texts; however, the term "meningitis" did not come into general use until surgeon John Abercrombie defined it in 1828.

Despite breakthroughs in diagnosis, treatment, and vaccination, in 2024, 2.5 million cases of bacterial meningitis were reported worldwide, with 300,000 subsequent deaths. The impact on prevention has been complicated by the increasing number of individuals who oppose routine vaccinations for their families, creating gaps in herd immunity and opportunities for outbreaks. Additionally, natural and man-made disasters have disrupted health care systems and vaccination delivery, with serious consequences for both children and adults.

Viral meningitis and aseptic meningitis are much more common than bacterial meningitis, and while both can potentially cause significant morbidity, these entities tend to be less severe in nature than bacterial meningitis.