Community-acquired acute meningitis and encephalitis: a narrative review

Area of Science:

• Neurology
• Infectious Diseases
• Public Health

Background:

• Meningitis and encephalitis are critical medical emergencies requiring immediate intervention to prevent mortality and long-term neurological damage.
• While conjugate vaccines have decreased bacterial meningitis rates, evolving drug resistance necessitates updated empiric treatment strategies.
• Non-infectious etiologies are common in encephalitis, underscoring the need for broad diagnostic approaches.

Purpose of the Study:

• To outline current best practices for the prompt evaluation and empiric management of meningitis and encephalitis.
• To highlight the role of specific diagnostic and therapeutic interventions, including vaccinations and adjunctive therapies.
• To emphasize the importance of timely treatment in improving patient outcomes.

Main Methods:

• Review of current clinical guidelines and evidence for the management of meningitis and encephalitis.
• Analysis of the impact of vaccinations on the incidence of infectious meningitis.
• Discussion of diagnostic modalities, including molecular testing and neuroimaging, and their appropriate use.
• Evaluation of empiric antibiotic and antiviral treatment strategies, including the role of ceftriaxone and aciclovir.
• Assessment of adjunctive therapies such as corticosteroids.

Main Results:

• Ceftriaxone is recommended for empiric treatment of bacterial meningitis due to changing drug sensitivities, emphasizing early administration.
• Neuroimaging is generally not required and can delay essential treatment for meningitis.
• Adjunctive corticosteroid therapy should be initiated before antibiotics in most adult meningitis cases.
• Molecular testing aids in diagnosing encephalitis, guided by exposure and geographic factors, while non-infectious causes must also be considered.
• Empiric treatment for encephalitis should target common pathogens like herpes simplex virus type 1 with intravenous aciclovir.
• Vaccinations offer protection against numerous viral and bacterial pathogens responsible for meningitis and encephalitis.

Conclusions:

• Rapid evaluation and empiric therapy are paramount for managing meningitis and encephalitis effectively.
• Optimized treatment strategies involve early administration of appropriate antibiotics (e.g., ceftriaxone), judicious use of neuroimaging, and consideration of adjunctive corticosteroids.
• Diagnostic approaches for encephalitis should encompass both infectious and non-infectious causes, with empiric therapy targeting prevalent pathogens like HSV-1.
• Vaccination remains a critical preventive measure against a wide spectrum of meningitis and encephalitis-causing agents.