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Meningitis
 Meningitis
caused by differnt M.O (bacteria,viruses, fungi .....etc)
but the commonest type of meningitis is bacterial meningitis
which caused primarily by 3 M.O:
1. Neisseria meningitidis. meningo-coccal meningitis.
2. Streptococcus pneumoniae
3. Haemophilus infuenzae type b (Hib).
 Those m.o constitutes
80-90% of all types of meningitis,
MENINGOCOCCAL MENINGITIS
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It is an acute bacterial disease characterized by sudden onset of
fever, intense headache, nausea, vomiting, neck stiffness ± pink
petechial rash (in 50%).The condition may progress to coma (vary
from cloudy consciousness to deep coma).
CFR: Before Rx > 50 %. ,After Rx → 8 – 15 %.
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In addition 10-20 % of survivors will suffer from long-term squeal as
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epilepsy, hearing loss (once cranial nerves damage occur, it never
return to normal).
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So the earlier the diagnosis, the least the complications and the
better the prognosis.
Diagnosis
1. Clinical picture.
2. CSF examination and culture (lumber puncture).
3. Blood culture.
Infectious agent:
Neisseria meningitidis, 12 sero-groups, only 5 of
which (A, B, C, and recently W-135 and X) can
cause epidemics. These are important in
prevention, control and vaccine preparation
Occurence
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Distribution world-wide.
Disease occurring sporadically, some time
endemic, and in small outbreaks in most part of the
world.
In Europe and North America the incidence of
meningococcal disease is higher during winter and
spring; in Sub-Saharan Africa the disease
classically peaks during the dry season.
Occurence
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Risk factors for meningococcal meneigitis includes
1) Age: Infants have the highest risk of meningococcal
disease & decrease after infancy and then increase in
adolescence and young adulthood.
2) Underlying immune deficiencies.
3) Crowding.
4) Low socioeconomic status.
5) Active or passive exposure to tobacco smoke.
6) Concurrent upper respiratory track tract infections
increase the risk of meningococcal disease.
Reservoir: Humans.
Mode of transmission:
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Direct contacts including respiratory droplets from
nose and throat of infected people.
Up to 10-20% of people may be asymptomatic
carrier with nasopharyngeal colonization. Less
than 1% of them progress to invasive disease.
Polluted fomites transmission is insignificant i.e.
indirect transmission is not an important route
(since the M.O is delicate one and easily
destroyed by U.V light and heat).
Incubation period: 2 – 10 days, commonly 3 – 4 days.
Period of communicability
 Without treatment until the M.O is no longer
present in nose and mouth discharges.
 But usually disappear from nasopharynx within 24
hours after start antibiotic treatment.
Susceptibility:
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Susceptibility to clinical disease is low and
decrease with age; this induces a higher ratio of
carriers to cases.
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Risk factors for meningococcal disease:age,
crowding, low socioeconomic status........etc.
Control and prevention
A.
1.
2.
3.
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Preventive measures:
Public health education about the need to reduce
droplet infection.
Avoid overcrowding .
Vaccines:
Vaccines containing groups A, C, Y and W-135
meningococcal polysaccharides are been
available.
Quadrivalent ACYW-135 vaccine is safe, effective
in adults & children above 2 years, but do not elicit
long term protection, particularly in children under 5
years of age.(so not used in routine childhood
immunization program).
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Quadrivalent A,C,Y,W-135 indicated in:
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Outbreak control.
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High risk groups:1. Hajj pilgrims, military groups.
2. Travelers to countries where disease is
epidemic.
 Reimmunization may be considered within 3–5 years if
indications still exist.
 No vaccine effective against group B meningococci
B) Control of patient, contacts and environment:
1. Reporting.
2. Isolation: respiratory isolation, usually at hospital for 24 hours
after start RX.
3. Concurrent disinfection & terminal disinfections.
4. Quarantine: not applicable.
5. Protection of contacts:
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Daily surveillance of house-hold contacts for early
signs and symptoms of illness.
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Prophylactic chemotherapy for house contacts, close
friends in schools, military personnel, young children
in day-care.
Antibiotic prophylaxis : Rifampicin (600 mg twice daily
for 2 days in adults, children over 1month old, 10
mg/kg; under 1 month, 5 mg/kg), or ciprofloxacin (500
mg, single dose).
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Generally immunization not recommended
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6. Specific Rx:
Penicillin in high doses given parenteral is the drug of
choice; ampicillin and chloramphenicol are also
effective.
Treatment should be start as early as possible, even
before identification of M.O.
The patient should be given rifampicin prior to
discharge from hospital to ensure elimination of the
M.O.
C- Epidemic measures:
1) Careful surveillance, early diagnosis, and immediate
treatment of suspected cases.
2) Immunization campaign must be implemented for children 25 years of age if an outbreak occur in a large institution when
group A,C,Y,W-135 are responsible.
3) Reduce overcrowding & ventilating living quarters.
4) Mass chemoprophylaxis is usually not effective in controlling
outbreaks, except for small population.
Haemophilus Meningitis
It was the most common bacterial M. in child aged 2
months – 5 years before Hib vaccine wide spread.
Infectious agent: Haemophilus infuenzae type b (Hib).
Occurrence: worldwide, 2 months – 3 years, unusual > 5
years.
Reservoir: Humans
I.P , period of communicability and susciptibility : same.
Method of control
A) preventive measures:
Vaccines: routine childhood immunization (introduce in
Iraq since end of 2011):
1st dose → age 2 months (Hib+DPT+HB)
2nd dose → age 4 months (Hib+DPT)
3rd dose → age 6 months (Hib+DPT+HB)
Booster → age 18 months (Hib+DPT)
B) Control of patient, contacts and environment:
 Protection of house contacts: By using rifampicin.
 Specific Rx: Ampicillin parenteral is drug of choice,
chloramphenicol, ceftriaxone are also effective. The
patient should be given rifampicin prior to discharge
from hospital.
Influenza
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Acute viral respiratory infection, characterized by
systemic manifestations fever, rigors, headache,
malaise & muscle pains with local manifestationsof coryza, sore throat and severe protracted cough.
The important complication is secondary bacterial
pneumonia.
Severe illness and death during annual influenza
epidemics (seasonal influenza) occur primarily among
elderly (80-90% of deaths occur in persons over 65 yrs)
and those debilitated by chronic illnesses.
The excess mortality varies and depends on the
prevalent virus type.
Infectiuos agents
Influenza Virus Types A, B & C according to antigenic
properties.
1. Type A usually associated with widespread epidemics
(seasonal flu) & pandemics (pandemic flu).
 Influenza A subtypes are classified depend on surface
Ag which are; Haemagglutinin H (H1, H2, H3)
&Neuraminidase N (N1, N2) Ag.
 Influenza A include 3 subtypes {H1N1, H2N2, H3N2}.
2. Type B is infrequently associated with regional or
widespread epidemics (seasonal flu).
3. Type C is associated with sporadic and minor localized
outbreaks.
Antigenic variation
o
Antigenic shift: Emergence of completely new virus
subtypes- at irregular intervals and only for type A virusesresult from antigenic shift in HA gene or unpredictable
recombination of human and mammalian or avian antigens
and lead to pandemics.
Type B has no animal reservoir → no antigenic shift.
o
Antigenic drift: The relatively minor antigenic changes or
spontaneous mutation (antigenic drift) of A & B viruses
responsible for frequent epidemics and regional outbreaks
which occur constantly (annually) and require annual
reformulation of influenza vaccine.
Occurence
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Pandemics (rare) -type A.
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Epidemics ( almost annual)-type A, B or both.
Localized out breaks and sporadic cases
(every year) –type C.
Pandemics of Influenza:
Is the emergence of the disease among
humans by new subtype of influenza viruses
with new surface proteins, and ranking as
global health emergencies, here children and
adults are equally susceptible.
e.g. 1889, 1918, 1957, 1968, 2009.
Occurrence
Influenza epidemic (seasonal flu):
 Attack rate during epidemics 10-20% in the
general community to more than 50 % in
closed community (schools).
 Epidemics generally last 3-6 weeks, usually
in winter, while outbreaks or sporadic cases
may occur in any month.
Reservoir:
-Human
Modes of transmission:
Airborne spread among crowded populations in
enclosed spaces.
- Direct contacts.
- Handling of contaminated articles.
I.P:
1-3 days.
Period of communicability:
3-5 days from clinical onset (adult). Up to 7 days
in young children.
Susceptibility & resistance
Infection produces immunity to the specific
antigenic variant of the infecting virus, and the
duration of immunity depend on the degree of
antigenic similarity between viruses causing
immunity.
Pandemics (emergence of new subtype) → all
susceptible.
Methods of control
A.
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Preventive measures:
Health education to the public about personal
hygiene to avoid unprotected cough and
sneezes, overcrowding etc.
Inactivated influenza vaccines (killed) derived
from A and B viruses that circulated during
previous season, 70-90% protection.Given at
autumn & repeated annually (routinely given for
those risky groups).It may cause low grade
fever and redness.2 doses one month apart,
repeated annually
Recently: live attenuated trivalent vaccine A
Given intranasal, promising results
Chemoprophylaxis (Anti-viral drugs)
Indication of vaccine
1. Healthy individuals >65 years (the vaccine less
effective in preventing infection but: ↓ severity, ↓
complications, ↓ death by 80%)
2. Individual with chronic diseasese.g. DM, renal
failure,haemoglobinopathies and
immunosuppresed.
3. Individual provides care to those at high risk
including close contacts and health staff.
3. Chemoprophylaxis of type A
Amantadine or rimantadine. Its effective
chemoprophylaxis of influenza A but not B (about
70-100 %).
 Same indications as vaccine.
 Chemoprophylaxis used when vaccine not
available or as a supplement to vaccine when
immediate maximal protection is desired against
type A.
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B) Control of pts, contacts and environment:
1.
2.
3.
4.
5.
6.
Reporting: Only for outbreaks.
Isolation: Impractical because of delay Dx.
Concurrent disinfection: Not Applicable.
Quarantine: Not Applicable.
Protection of contacts: by chemoprophylaxis.
Investigation of contacts and source of
infection: None.
7. Specific Rx: Amantadine or rimantadine
100 mg twice daily, within 48 hrs of onset of
illness and for 3-5 days can reduce symptoms
and virus titer in respiratory secretion.
- Rx of secondary bacterial infections.
- Avoid salicylates in children.
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