Transcript Bordetella pertussis) a gram-negative pleomorphic bacillus

Pertussis Syndrome
By
DR; RIADH ALOBAIDI
ETIOLOGY
• The pertussis is MOSTLY disease caused by
Bordetella pertussis )a gram-negative
pleomorphic bacillus ( . Vaccine for this
available DPT
• Bordetella parapertussis, which causes a
similar but milder illness that is not affected
by B. pertussis vaccination
• Adenoviruses have been associated with the
pertussis syndrome.
EPIDEMIOLOGY
• The mean incubation period is7-10 days ,
range 4-21 days.
• pertussis is very common and important to
know this illness.It is called one( month cough
disease).
• Patients are most infectious during the
catarrhal stage till after 3 weeks of coughing
stage.Three stages each 2wks durations
catarrhal,paroxysmal,convalescent
CLINICAL MANIFESTATIONS
pertussis is the syndrome seen in most infants 1-month to
school age. The progression of the disease is divided into:
1. The catarrhal stage is marked by nonspecific signs
(upper respiratory tract infection as running nose,
sneezing and low-grade fever) that last 1wk.
2. The paroxysmal stage :coughing stage; is the most
distinctive classic stage of pertussis. Coughing occurs
in paroxysms (episodes) during expiration, causing
young children above 6 months to lose their breath
and even apnea followed by high pitch inspiratory
sound -whoop
The forceful inhalation against a narrowed glottis that
follows this paroxysm of cough produces the
characteristic whoop .
Post-tussive emesis should raise the suspicion of
pertussis .Facial congestion and cyanosis may be
seen in the attack. This stage lasts 2- weeks. Pertussis
may produce anoxic brain damage and even
encephalopathy.
3. The convalescent stage is marked by gradual
resolution of symptoms over 1 to 2 weeks. Coughing
becomes less severe, residual cough may persist for
months
Infants below 3 months and neonates may get the
illness due to lack of maternal immunity,may not give
the classic pertussis syndrome; the first signs may be
episodes of repetitive coughing and some may
develops apnea.. Adolescents and adults with
pertussis usually present with a prolonged cough
without whoops many weeks to months. Physical
examination is nonspecific
LABORATORY AND IMAGING STUDIES
1. Culture of nasopharyngeal swabs.
2. Direct fluorescent antibody staining of the swab
from nasopharynx.
3. PCR is useful .
4. Leukocytosis (15,000–30,000 cells/mm3) due to
absolute lymphocytosis.
5. Radiological X-R ; not specific, It may show
segmental lung atelectasis to develop during
pertussis, especially during the paroxysmal
stage. Perihilar infiltrates are common and are
similar to what is seen in viral pneumonia.
Secondary bacterial pneumonia may develop.
DIFFERENTIAL DIAGNOSIS
1. Respiratory viruses such as RSV, parainfluenza
virus, and Chlamydia pneumoniae can
produce bronchitic illnesses among infants.
2. In older children and young adults,
Mycoplasma pneumoniae may produce a
prolonged bronchitic illness that is not
distinguished easily from pertussis in this age
group.
TREATMENT
Erythromycin,, or Azithromycin if given early in the course
of illness it eradicates organisms within first 3 to 4 days
in (catarrhal stage), and it abort and stop the course of
infection. Treatment is indicated during the first 3 weeks
of whooping cough stage illness to reduce the severity
and infectivity, but it does not treat the the coughing.
Antibiotics reduce the risk of infectivity to contacts when
given for full 5 days course during the infectivity period
(first 3 wks of coughing illness). It also should be given to
contacts members regardless of their vaccination. When
given to neonates pt. younger than 4 weeks old,
clarythromycin or erythromycin may rarely been
associated with pyloric stenosis, but treatment is still
recommended because of the seriousness of pertussis in
this age. Azithromycin has less such side effect and is
drug of choice for neonates for 5 days.
COMPLICATIONS
1. Hypoxia
2. Apnoea specially in young infants.
3. Pneumonia : caused by B. pertussis itself or
resulting from secondary bacterial infection
4. seizures, encephalopathy
5. failure to thrive.
6. Atelectasis may develop
7. The force of the paroxysm may rupture alveoli
and produce pneumothorax,
8. epistaxis; and retinal and subconjunctival
hemorrhages, hernia
9. Otitis media and sinusitis may occur.
Infants <4 mo of age account for 90% of cases
of fatal pertussis
PREVENTION
Active immunity can be induced with acellular
pertussis vaccine, given in combination with the
toxoids of tetanus and diphtheria (DTaP).
Pertussis vaccine has an efficacy of 70% .the
efficacy declines if fewer vaccinations given.
Compared with older, whole cell pertussis vaccines,
acellular vaccines have fewer adverse effects and
local reactions .
Patient who have pertussis produce life long
immunity.
Erythromycin is effective in preventing disease
in contacts exposed to pertussis. Close
contacts younger than 7 years old who have
received four doses of vaccine should receive
a booster dose of DTaP.They also should be
given erythromycin. Close contacts older than
age 7 should receive only prophylactic
erythromycin 5 days, but not the vaccine.
Immune deficiency status
• Immunity depend on humoral antibodies produced
by B-lymphocytes ,and complements.
• While cellular immunity depends on T-lymphocytes,
and neutrophils.
Humoral antibodies is mainly to bacterial infection .
Cellular T-CELL mainly to viral and fungal infection.
May be primary due to genetic defects or inherited or
may be secondary causes like AIDS or malignancy or
drugs.
PRESENTATIONS OF IMMUNE DEFICIENCY
• Recurrent bacterial infections.
• Severe bscterial infections; like meningitis and
sepsis.
• Infections with unexpected opportunistic m.o.
• Extensive candidiasis.
• Abscesses any where in the body skin or
internal organs.
• Delayed separation of umbilical cord in
newborn.
HIV infection AIDS
Route of infection is mother to child by
transplacental or during delivery or by breast
feeding from infected mother. To children may
be by blood products or unsterile needles.
Diagnostic tests
• Less than 18 months born to infected mother
is by HIV DNA- PCR.
• For older than 18 m.is by antibodies and
antigens of HIV .
Clinical features of AIDS
• May remain sublinical for 1yr in infants and for
many months for children untill symptoms
appears ; as prolonged fever PUO, faiure to
thrive. chronic diarrhea, candidiasis TB,
lymphadenitis,hepatosplenomegaly, serious
infections.