What's new in bacterial meningitis

Acute Bacterial Meningitis in Healthy Adult Patients: A Prospective Cohort Study

Spontaneous bacterial meningitis (BM) is more common among patients with underlying conditions, but its characteristics in previously healthy patients are not well described. We analyzed the time trends of BM in terms of characteristics, and outcomes in patients without comorbidities.

PATIENTS AND METHODS

Single-center, prospective observational cohort study of 328 adults with BM hospitalized in a tertiary university hospital in Barcelona (Spain). We compared the features of infections diagnosed in 1982-2000 and 2001-2019. The main outcome measure was in-hospital mortality.

RESULTS

The median age of the patients increased from 37 to 45 years. Meningococcal meningitis significantly diminished (56% versus 31%, p < 0.000) whereas listerial meningitis increased (1.2% versus 8%, p = 0.004). Systemic complications were more common in the second period, although mortality did not vary significantly between periods (10.4% versus 9.2%). However, after adjusting for relevant variables, infection in the second period was associated with lower risk death.

CONCLUSIONS

Adult patients without underlying comorbidities that developed BM in recent years were older and more likely to have pneumococcal or listerial infections and systemic complications. In-hospital death was less likely in the second period, after adjusting for risk factors of mortality.

Neurological Emergencies in the Intensive Care Unit

Neurological emergencies carry significant morbidity and mortality, and it is necessary to have a multidisciplinary approach involving the emergency physician, the neurologist, the intensivist, and the critical care nursing staff. These disorders can be broadly divided into noninfectious and infectious etiologies. In this article, we review a few of the neurological emergencies that present to the neurological intensive unit, with emphasis on convulsive status epileptics, myasthenia gravis, Guillain-Barré syndrome, meningitis, encephalitis, and brain abscess.

Bacterial Meningitis in Children: Neurological Complications, Associated Risk Factors, and Prevention

Bacterial meningitis is a devastating infection, with a case fatality rate of up to 30% and 50% of survivors developing neurological complications. These include short-term complications such as focal neurological deficit and subdural effusion, and long-term complications such as hearing loss, seizures, cognitive impairment and hydrocephalus. Complications develop due to bacterial toxin release and the host immune response, which lead to neuronal damage. Factors associated with increased risk of developing neurological complications include young age, delayed presentation and Streptococcus pneumoniae as an etiologic agent. Vaccination is the primary method of preventing bacterial meningitis and therefore its complications. There are three vaccine preventable causes: Haemophilus influenzae type b (Hib), S. pneumoniae, and Neisseria meningitidis. Starting antibiotics without delay is also critical to reduce the risk of neurological complications. Additionally, early adjuvant corticosteroid use in Hib meningitis reduces the risk of hearing loss and severe neurological complications.

Community-acquired acute meningitis and encephalitis: a narrative review

Meningitis and encephalitis are medical emergencies. Patients need prompt evaluation and immediate empiric therapy to reduce the likelihood of fatal outcomes and chronic neurological sequelae. Conjugate bacterial vaccines have significantly reduced the incidence of bacterial meningitis, especially in children. As the results of changes in patterns of bacterial drug sensitivity, ceftriaxone is now part of the recommended empiric treatment for bacterial meningitis and should be administered as early as possible. Neuroimaging delays the treatment of meningitis and is not needed in most cases. Adjunctive corticosteroid therapy is of benefit for many patients with meningitis and should be initiated in most adults before antibiotic therapy. Molecular testing can assist the specific diagnosis of encephalitis and should be based on the exposure history and geographic risk factors relevant to the patient, but non-infectious causes of encephalitis are also common. Empiric therapy for encephalitis should be directed at the most frequently identified infectious pathogen, herpes simplex virus type 1 (ie, intravenous aciclovir). Vaccines can protect against the major pathogens of childhood infections (measles, mumps, rubella, polio, varicella viruses), influenza viruses, and exotic pathogens that cause meningitis and encephalitis (rabies, Japanese encephalitis, dengue, yellow fever, tick-borne encephalitis viruses, Mycobacterium tuberculosis).

Meningococcal disease, a clinical and epidemiological review

Meningococcal disease is the acute infection caused by Neisseria meningitidis, which has humans as the only natural host. The disease is widespread around the globe and is known for its epidemical potential and high rates of lethality and morbidity. The highest number of cases of the disease is registered in the semi-arid regions of sub-Saharan Africa. In Brazil, it is endemic with occasional outbreaks, epidemics and sporadic cases occurring throughout the year, especially in the winter. The major epidemics of the disease occurred in Brazil in the 70's caused by serogroups A and C. Serogroups B, C and Y represent the majority of cases in Europe, the Americas and Australia. However, there has been a growing increase in serogroup W in some areas. The pathogen transmission happens for respiratory route (droplets) and clinically can lead to meningitis and sepsis (meningococcemia). The treatment is made with antimicrobial and supportive care. For successful prevention, we have some measures like vaccination, chemoprophylaxis and droplets' precautions. In this review, we have described and clarify clinical features of the disease caused by N. meningitidis regarding its relevance for healthcare professionals.

Community-acquired bacterial meningitis

Meningitis is an inflammation of the meninges and subarachnoid space that can also involve the brain cortex and parenchyma. It can be acquired spontaneously in the community - community-acquired bacterial meningitis - or in the hospital as a complication of invasive procedures or head trauma (nosocomial bacterial meningitis). Despite advances in treatment and vaccinations, community-acquired bacterial meningitis remains one of the most important infectious diseases worldwide. Streptococcus pneumoniae and Neisseria meningitidis are the most common causative bacteria and are associated with high mortality and morbidity; vaccines targeting these organisms, which have designs similar to the successful vaccine that targets Haemophilus influenzae type b meningitis, are now being used in many routine vaccination programmes. Experimental and genetic association studies have increased our knowledge about the pathogenesis of bacterial meningitis. Early antibiotic treatment improves the outcome, but the growing emergence of drug resistance as well as shifts in the distribution of serotypes and groups are fuelling further development of new vaccines and treatment strategies. Corticosteroids were found to be beneficial in high-income countries depending on the bacterial species. Further improvements in the outcome are likely to come from dampening the host inflammatory response and implementing preventive measures, especially the development of new vaccines.