From the Guidelines
Meningitis is a severe and potentially life-threatening inflammation of the protective membranes covering the brain and spinal cord, caused by various factors including bacterial, viral, fungal, and parasitic infections, as well as non-infectious triggers. The main causes of meningitis include bacterial infections, such as those caused by Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae, which are the most severe forms and require immediate antibiotic treatment 1. According to the UK Joint Specialist Societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults, the incidence of meningitis in adults has remained stable or increased, with a mortality rate of approximately 20% for all causes and up to 30% in pneumococcal meningitis, increasing with age 1. The types of meningitis include:
- Bacterial meningitis, which is the most severe form and requires immediate antibiotic treatment
- Viral meningitis, which is generally less severe and resolves without specific treatment
- Fungal meningitis, which often occurs in immunocompromised patients and requires antifungal medications
- Parasitic meningitis, which is rare but can be caused by organisms like Angiostrongylus cantonensis
- Non-infectious meningitis, which may require corticosteroids or other immunosuppressants Symptoms of meningitis typically include fever, headache, neck stiffness, and altered mental status, and prevention includes vaccines against common bacterial causes, practicing good hygiene, and avoiding close contact with infected individuals 1. Prompt medical attention is crucial, especially for suspected bacterial meningitis, as delayed treatment can lead to serious complications including brain damage, hearing loss, or death. The ESCMID guideline on the diagnosis and treatment of acute bacterial meningitis also emphasizes the importance of prompt and appropriate treatment, taking into account the increasing rate of reduced susceptibility to common antimicrobial agents among strains of Streptococcus pneumoniae and Neisseria meningitidis 1. Key considerations and risk factors for the likelihood of specific aetiology include age, immune status, and exposure history, and the diagnosis of meningitis is typically made based on a combination of clinical presentation, laboratory tests, and imaging studies 1. In many cases, no pathogen is identified, highlighting the need for a thorough diagnostic workup and empiric treatment based on regional epidemiology and resistance patterns 1. Overall, meningitis is a serious and potentially life-threatening condition that requires prompt and appropriate treatment to prevent complications and improve outcomes.
From the Research
Causes of Meningitis
- Bacterial meningitis is caused by bacteria such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae, which are responsible for most cases diagnosed in children, adolescents, and adult population 2, 3, 4, 5
- These bacteria can colonize the nasopharynx and may invade the bloodstream to cause systemic infections and meningitis 5
- Streptococcus agalactiae (group B Streptococcus) is also an important meningitis agent, particularly in newborns, and can cause invasive infections in infants or adults 5
Types of Meningitis
- Bacterial meningitis: caused by bacteria such as Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae 2, 3, 4
- Vaccine-preventable bacterial meningitis: caused by Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, and Streptococcus agalactiae, which can be prevented by conjugate vaccines 5
- Meningitis can be classified based on the causative agent, such as Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, and Streptococcus agalactiae 5
Diagnosis of Meningitis
- Laboratory diagnosis of bacterial meningitis can be done using culture, PCR, and other molecular techniques 2, 3, 4
- PCR can provide better sensitive diagnostic tests than culture, particularly when antimicrobial treatment is initiated before clinical samples can be obtained 2, 3, 4
- Multiplex PCR can detect multiple pathogens simultaneously, increasing the diagnostic yield for bacterial meningitis 3, 4