Meningococcal meningitis
Meningococcal meningitis (MM) is a severe bacterial infection characterized by inflammation of the membranes surrounding the brain and spinal cord. Primarily caused by the bacterium Neisseria meningitidis, MM can lead to rapid and serious health complications, including severe brain damage and death if not treated promptly. The disease is spread through respiratory droplets, making close contact with infected individuals a risk factor for transmission. Symptoms often manifest as intense headaches, fever, nausea, stiff neck, and sometimes a distinctive petechial rash. Diagnosis of MM can be challenging due to symptom overlap with other illnesses, but it typically involves clinical evaluation and lumbar puncture to analyze spinal fluid.
Prevention strategies include vaccination, which is the most effective method to reduce the risk of infection, particularly among high-risk groups like college students in dormitories and populations experiencing outbreaks. Various vaccines are available, targeting multiple serogroups of N. meningitidis. Treatment primarily involves antibiotics, with early administration being crucial for positive outcomes. Awareness of symptoms and timely medical intervention are essential for managing this potentially life-threatening condition effectively.
Meningococcal meningitis
- ANATOMY OR SYSTEM AFFECTED: Brain, central nervous system, spinal cord
- ALSO KNOWN AS: Meningococcal disease
Definition
Meningococcal meningitis (MM) is an invasive bacterial form of meningitis, an infection that causes swelling and inflammation of the thin lining (membrane) that surrounds the brain and spinal cord. MM, which can cause severe brain damage and is fatal if untreated, was first described clinically in 1805 in Switzerland following an outbreak in Geneva.
Causes
MM is caused by several different bacteria, including Neisseria meningitidis, a gram-negative diplococcus bacterium found exclusively in humans. Other bacteria, including Streptococcus pneumoniae and Haemophilus influenzae also cause it. Based on the capsular polysaccharide, a minimum of thirteen different serogroups of N. meningitidis have been identified. Serogroups A, B, and C have been recognized as significant causes of meningococcal disease.
Risk Factors
Risk factors for the invasive disease may be a combination of host, environment, and organism strain. Recent respiratory tract infection, low socioeconomic status, and a susceptible population increase vulnerability. Climatic factors also influence seasonal outbreaks. In Africa, epidemics begin during the dry season; in temperate countries, sporadic illness and epidemics appear during the late winter and early spring.
MM is spread through direct contact with respiratory droplets of infected people. Therefore, it can spread through close and prolonged contact with others, sneezing or coughing, and living close to an infected person.
Symptoms
The clinical manifestations of meningococcal disease can be varied, ranging from transient fever and the presence of bacteria in the blood (bacteremia) to fulminate disease and death occurring within hours of clinical onset. Symptoms include intense headache, fever, nausea, vomiting, photophobia, stiff neck, lethargy, myalgia, and a characteristic petechial rash.
Screening and Diagnosis
MM is difficult to diagnose outside epidemics because symptoms mimic many other illnesses. Initial diagnosis can be made by clinical examination followed by a lumbar puncture showing a purulent spinal fluid. The bacteria can sometimes be seen in microscopic examinations of the spinal fluid.
Treatment and Therapy
Antimicrobial chemoprophylaxis is the primary means of preventing the transmission of invasive meningococcal disease from patients to close contacts. Identifying the N. meningitidis serogroups and their susceptibility tests to antibiotics is important for treatment and control measures. Antibiotics, such as penicillin, ampicillin, chloramphenicol, ceftriaxone, and fluoroquinolones, such as ciprofloxacin, can treat the infection.
Prevention and Outcomes
Several surveillance data conclude that immunization with a meningococcal vaccine offers the best intervention strategy. Routine vaccination is also recommended for high-risk groups, including first year college students living in dormitories, travelers, populations experiencing outbreaks of meningococcal disease, and persons with increased susceptibility.
There are several types of effective and safe vaccines for preventing MM. Meningococcal conjugate vaccines are the most widely used. These types of vaccines include quadrivalent, which protects against serogroups A, C, W, and Y, and pentavalent, a newer vaccine which protects against serogroups A, C, W, Y, and B. Designed exclusively to protect against serogroup B are serogroup B meningococcal vaccines, which are commonly used in children and young adults. Meningococcal polysaccharide vaccines are also used for serogroups A, C, Y, and W, but these are older and less effective in vulnerable populations. Bivalent and trivalent polysaccharide vaccines have become outdated and are no longer used for MM. Finally, newer outer membrane protein vaccines that target serogroup B have become widely available in the twenty-first century.
Bibliography
"About Meningococcal Vaccines." CDC, 20 Nov. 2023, www.cdc.gov/vaccines/vpd/mening/hcp/about-vaccine.html. Accessed 26 Sept. 2024.
"Clinical Guidance for Meningococcal Disease." CDC, 21 Aug. 2024, www.cdc.gov/meningococcal/hcp/clinical-guidance/index.html. Accessed 26 Sept. 2024.
Klein, D. L., and R. W. Ellis. "Conjugate Vaccines Against Streptococcus pneumoniae." In New Generation Vaccines, edited by M. M. Levine, at al. 2d ed., New York: Marcel Dekker, 1997.
Kvalsvig, A. J., and D. J. Unsworth. "The Immunopathogenesis of Meningococcal Disease." Journal of Clinical Pathology, vol. 56, 2003, pp. 417-422.
Pollard, A. J. "Global Epidemiology of Meningococcal Disease and Vaccine Efficacy." Pediatric Infectious Disease Journal, vol. 23, 2004, pp. S274-S279.
World Health Organization. Control of Epidemic Meningococcal Disease. 2d ed., Geneva: Author, 1998.