Dr.WijdanCommunity MedicineMeningitis
Meningococcal Disease and Meningococcal VaccinesMeningitis
Infection causing inflammation of the membranes covering the brain and spinalcord
Medical emergency with significant mortality
Characteristic pathogens
1. Bacterial meningitis or purulent meningitis
2. Non-bacterial meningitis often referred to as aseptic meningitis
Aseptic Meningitis
All non-bacterial causes of meningitis
Typically less ill appearing than bacterial meningitis
Most common cause is viral
Viral Meningitis : A relatively common but rarely serious clinical syndrome
with multiple viral etiology , characterized by sudden onset febrile illness
with sign of meningeal involvement.
Infectious agents:
A wide variety of infectious agents exist , many associated with other specific
diseases. In epidemic period mumps may be responsible for more than 25% of cases
of non immunized etiology.
Occurrence: worldwide , as epidemic and sporadic cases, true incidence unknown.
Seasonal increase in the summer and early autumn are due mainly to arboviruses
and enteroviruses, while late winter outbreaks may be due primarily to mumps
CSF findings are pleocytosis( usually mononuclear, occasionally
polymorphonuclear in early stages) increased protein, normal sugar and absence
of bacteria. A rubella like rash characterizes certain types caused by
echoviruses, vesicular and petechial rash may occur. Active illness seldom
exceeds 10 days. Recovery may be complete
Bacterial Meningitis:
Most frequent in children age 2 months to 2 years of ageHigher incidence during winter and spring Neisseria meningitidis, Streptococcus
pneumoniae and Hemophilus influenza type b cause more than 75% of all cases of
bacterial in most study and 90% of bacterial meningitis in children. Previously
Hemophilus influenza type b is the most common cause of bacterial meningitis has
been largely eliminated by immunization programs.
Neisseria meningitidis
Severe acute bacterial infection.Cause of meningitis, sepsis, and focal infections.
Epidemic disease in sub-Saharan Africa
Current polysaccharide vaccine licensed in 1978
Conjugate vaccine licensed in 2005
Neisseria meningitidis
Aerobic gram-negative bacteria
At least 13 serogroups based on characteristics of the polysaccharide capsule
Most invasive disease caused by serogroups A, B, C, Y, and W-135
Relative importance of serogroups depends on geographic location and other
factors (e.g. age)
Meningococcal Disease
Pathogenesis
Organism colonizes nasopharynx
Nasal carrier in 25% of 18y-25y.
In some persons organism invades bloodstream and causes infection at distant
site
Antecedent URI may be a contributing factor
Meningococcal Disease
Clinical Features
Incubation period 3-4 days (range 2-10 days)
Abrupt onset of fever, meningeal symptoms, hypotension, and rash
Fatality rate 9%-12%; up to 40% in meningococcemia
Neisseria meningitidis
Clinical Manifestations*
Meningococcal Meningitis
Most common pathologic presentation
Result of hematogenous dissemination
Clinical findings:
Fever
headache
stiff neck
petechial/purpuric rash
hypotension
multiorgan failure
Meningococcemia
Meningococcemia is defined as dissemination of meningococci into the bloodstreamand is a medical emergency, making early recognition of the disease.
Patients with acute meningococcal infection can present clinically with one of 3
syndromes: meningitis, meningitis with meningococcemia, or meningococcemia
without obvious meningitis. Prior to the advent of antibiotics, almost all cases
resulted in death or marked morbidity.
Meningococcal Disease
Laboratory Diagnosis
The gold standard for diagnosis is recovery of meningococci from a sterile site(
CSF, OR BLOOD) Bacterial culture
Gram stain
Non-culture methods
Antigen detection in CSF
Serology
Epidemiology
Frequency
International
Serogroups A, B, and C account for most cases worldwide. Serogroups A and Cpredominate in Asia and Africa, and serogroups B and C predominate in Europe,
North America, and South America.
For more than a century, serogroup A meningococcal disease has been endemic in
the African Meningitis Belt, which extends from Ethiopia in eastern Africa to
Senegal in West Africa.
Outbreaks of meningococcal disease occurred during the annual hajj (pilgrimage)
in Saudi Arabia in 2000 and 2001 among pilgrims and household contacts Outbreakshave also occurred in Africa, parts of Asia, South America, and the former
Soviet republics. Serogroup A is usually implicated in these epidemics.
Outbreaks are also occasionally reported in the United States.
Meningococcal disease may be a significant but under-reported problem in
developing Asian countries.Serogroup W-135 has been associated with pilgrims returning from the hajj.
Up to 95% of patients with meningococcal disease have meningococcemia and/or
meningitis. Up to 50% have meningococcemia without meningitis. Fulminant
meningococcemia occurs in up to 20%.
Nosocomial transmission to patient care personnel and laboratory staff is rare.
Neisseria meningitidis
Medical Management
Initial empiric antibiotic treatment after appropriate cultures are obtained
Treatment with penicillin alone recommended after confirmation
of N.
Occurrence:
In Europe and North America the incidence of the disease is higher during winter
and spring.
In Sub-Saharan Africa the disease classically peaks during dry season.
Risk Factors:
1. Age: Infants have the highest risk of the disease . Rates decrease after
infancy and then increase in adolescence and young adulthood.
In some countries : male are at higher risk than female
2. Immune deficiency:
2. Terminal complement pathway deficiency
4. Asplenia( absence of the spleen).
, functional asplenia impaired reticuloendothelial function of the spleen, as
seen in children with sickle cell anemia.
5. Genetic risk factors
Exposure factors
6. Household exposure
7. Demographic and socioeconomic factors and crowding
8. Concurrent upper respiratory tract infection
9. Active and passive smoking
Meningitis-Differential Diagnosis
• •Brain abscess
• •Encephalitis
• •Epidural abscess
• •Bacterial endocarditis with septic embolism
• •Subarachnoid hemorrhage
• •Tumor
Meningococcal Disease
Epidemiology• •Reservoir Human
• •Transmission Respiratory droplets
• •Temporal pattern Peaks in late winter–early spring
• •Communicability Generally limited
Methods of control
Preventive measures:1. Educate the public on the need to reduce direct contact and exposure to
droplet infection.
2. Quadrivalent meningococcal polysaccharide vaccine containing groups (A, C, Y,
W-135) ,
( bivalent AC) two polysaccharide vaccines are currently available on the
market
Administered by subcutaneous injection
10-dose vial contains thimerosal as a preservative
Vaccine Recommendations
• •(bivalent AC) two polysaccharide vaccines approved for persons 2
years of age and older, do not elicit long term protection particularly in
children under 5. Serogroup A polysacharide can induce antibodies in children as
young as 3 months ,but C polysacharide is poorly immunogenic and not effective
in children under 2.
• •Not recommended for routine vaccination of civilians
• •Should be used only for persons at increased risk of N.
meningiditis infection who are 56 years of age or older, outbreak control and
for prevention of among high risk group.
Meningococcal Vaccine
Recommendations
• •Recommended for persons at increased risk of meningococcal disease:
Microbiologists who are routinely exposed to isolates of N. meningitidis
Military recruits
Persons who travel to and U.S. citizens who reside in countries in which N.
meningitidis is hyperendemic or epidemic
terminal complement component deficiency
functional or anatomic asplenia
Meningococcal Vaccine Recommendations
• •Because these vaccines are often poorly immunogenic in young
children and have limited duration of efficacy they are not generally used in
routine child hood examination programs. Re immunization may be considered
within 3-5 years
• • Outbreak definition:
10. 3 or more confirmed or probable primary cases
11. Period <3 months
12. Primary attack rate >10 cases per 100,000 population.
Meningococcal Vaccines
Contraindications and Precautions• •Severe allergic reaction to vaccine component or following prior
dose of vaccine
• •Moderate or severe acute illness
Meningitis- Prevention
• •Chemoprophylaxis for close contacts of index case if Neisseria;treat contacts less than 4 years of age.
• •Vaccinate all children, especially those at risk or those with a
splenia
Control of patient, contacts and the immediate environment:
1. Report to local health authority.
2. Isolation : for 24 hours after start chemotreatment.
3. Concurrent disinfection.
Protection of contacts: close surveillance of household day care and other
intimate contact for early signs of illness
Specific treatment: penicillin given paranterally in adequate dose is the drug
of choice, ampicilline and chloramphinicol are also effective.