pertussis and certain other infectious
- Classic pertussis, whooping
cough syndrome, is caused by B. pertussis, a gram-negative
pleomorphic bacillus with fastidious growth requirements
- infect only humans
- transmitted person to person by
- Adenoviruses have been associated
with pertussis syndrome
- The mean incubation period is 6
- Patients are most contagious
during the earliest stage.
- The peak age is less than 4 months
of age-among infants too young to be completely immunized and most likely to
have the complications of pneumonia and severe infection that are associated
with a high mortality rate
between 1 and 10 years of age:
- catarrhal stage is marked by nonspecific signs (injection, increased
nasal secretions, and low-grade fever) lasting 1 to 2 weeks.
- paroxysmal stage is the most distinctive stage of pertussis and lasts 2
to 4 weeks. Coughing occurs in paroxysms during expiration, causing
young children to lose their breath. The forceful inhalation against a
narrowed glottis that follows this paroxysm of cough produces the characteristic
whoop. Post-tussive emesis is common.
- convalescent stage is marked by gradual resolution of symptoms over 1 to 2
weeks. Coughing becomes less severe, and the paroxysms and whoops slowly
disappear. Although the disease typically lasts 6 to 8 weeks, residual
cough may persist for months
- may not display the classic pertussis syndrome. The
first sign in the neonate may be episodes of apnea. Young infants are
unlikely to have the classic whoop, more likely to have central nervous
system (CNS) damage as a result of hypoxia, and more likely to have
secondary bacterial pneumonia.
- and adults with pertussis usually present with a
prolonged bronchitic illness with persistent, nonproductive cough that
often begins as a nonspecific upper respiratory tract infection.
is present in 75% to 85%.
- WBC may increase from 20,000 cells/mm3 to more
than 50,000 cells/mm3
- It is not unusual for physical and radiographic signs of
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
For a young child with classic
pertussis syndrome, the diagnosis based on the pattern of illness is quite
The paroxysmal stage is the most distinctive
part of the syndrome.
- infants :Respiratory viruses such
as RSV, parainfluenza virus, and Chlamydophila pneumoniae can produce
- 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.
Erythromycin, clarithromycin, or
azithromycin are recommended for children under 1 month of age.
Azithromycin should be used in
neonates due to the association of erythromycin treatment and the development
of pyloric stenosis.
Treatment is not effective in
the paroxysmal stage.
apnea, pneumonia, seizures, encephalopathy, malnutrition. Pneumonia
Atelectasis . pneumomediastinum, pneumothorax, or interstitial or
subcutaneous emphysema; epistaxis; hernias; and retinal and subconjunctival
hemorrhages. Otitis media.
permanent disability is a result of encephalopathy
- Close contacts under 7 years of
age who have received only four doses
of vaccine should receive a booster dose of DTaP (unless a booster dose has
been given within the preceding 3 years) and a macrolide antibiotic for 10 to
- Close contacts 7 years of age and
older should receive prophylactic
macrolide antibiotic for 10 to 14 days and Tdap, although the effectiveness
of this strategy has not yet been determined.
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[ پنجشنبه 10 بهمن 1392 ] [ 01:15 بعد از ظهر ] [ گرند راند