Pediatrics

Pertussis andPertussis syndrome

Zhi-min Chen

Dept. Pediatric Pulmonology, Children’s Hospital

Zhejiang University School of Medicine

Definition

Pertussis (whooping cough)

caused by Bordetella pertussis,

The pertussis syndrome

includes disease caused by Bordetella pertussis

and certain other infectious agents

Etiology

Bordetella pertussis

Gram-negative

Other infectious agents

Bordetella parapertussis

Adenovirus

Dual infection (of above)

Other common pathogens of protracted cough:

mycoplasma, chlamydia, RSV, parainfluenza virus

Epidemiology

Infect only humans and transmitted person

to person by coughing

Most contagious during the earliest stage

The peak incidence <4 m

The annual rate--100 to 200/100,000, higher

in developing countries

Clinical manifestation

The mean incubation period is 6 days.

The progression of pertussis

Catarrhal stage

Paroxysmal stage

Convalescent stage

Clinical manifestation

Catarrhal stage

nonspecific signs

• Injection

• increased nasal secretions

• low-grade fever

last 1 to 2 weeks

Clinical manifestation

The paroxysmal stage

approximately 2 to 4 weeks.

as catarrhal symptoms wane, coughing begins first

as a dry, intermittent, irritative hack;

then evolve into coughing in paroxysms during

expiration, causing young children to lose their

breath (machine-gun burst of uninterrupted

coughs).

Clinical manifestation

The paroxysmal stage After the most insignificant startle from a draught,

light, sound, sucking or stretching, a well-appearing young infant begins to choke, gasp, and flail extremities, eyes watering and bulging, face reddened or purple, tongue protruding maximally until at the seeming last moment of consciousness.

Characteristic whoop follows this paroxysm of cough (the forceful inhalation against a narrowed glottis).

Others: post-tussive emesis, conjunctival hemorrages and petechiae on the upper body

Clinical manifestation

The Convalescent stage

gradual resolution of symptoms over

1 to 2 weeks.

residual cough may persist for

months, especially with physical

stress or respiratory irritants

Clinical manifestation

Young infants may not display the classic

pertussis syndrome: the first signs may be episodes of apnea

unlikely to have the classic whoop

more likely to have CNS damage as a result of

hypoxia

more likely to have secondary bacterial

pneumonia.

LABORATORY STUDIES

The diagnosis depends on isolation of B. pertussis Culture of nasopharyngeal swabs

Direct fluorescent antibody staining

Serologic tests are not useful for diagnosis of acute infection.

Leucocytosis (20,000~ 50,000/mm3) with lymphocytosis is characteristic beyond the neonatal age

IMAGING STUDIES

NOT specific

Segmental lung atelectasis

not unusual during pertussis, especially during the

paroxysmal stage.

Perihilar infiltrates

common and similar to what is seen in viral

pneumonia.

Diagnosis and differential diagnosis

the diagnosis based on recognition of the

pattern of illness is quite accurate

Respiratory viruses such as RSV, parainfluenza

virus, and C. pneumoniae among infants and

M. pneumoniae in older children may produce a

bronchitic illness that is not distinguished

easily from pertussis.

Complications

Major complications:hypoxia, apnea, pneumonia,

seizures, encephalopathy, and malnutrition.

The most frequent complication is pneumonia

caused by B. pertussis itself or resulting from

secondary bacterial infection from S.

pneumoniae, Hib, and S. aureus.

Complications

Other complications

atelectasis, pneumomediastinum,

pneumothorax, or interstitial or

subcutaneous emphysema; epistaxis;

hernias; and retinal and subconjunctival

hemorrhages, otitis media and sinusitis .

Goal of therapy

Limit the number of paroxysms

Observe the severity of cough to provide

assistance when necessary

Maximize nutrition, rest, and recovery

without sequelae

Treatment

Erythromycin given early, eradicates nasopharyngeal carriage

of organisms within 3 to 4 days and ameliorates the effects of the infection.

not effective in the paroxysmal stage.

Azithromycin and clarithromycin

TMP-SMZ

Pertussis-specific immunoglobulin ( effective)

PREVENTION

Active immunization

acellular pertussis vaccine, given in

combination with the toxoids of tetanus

and diphtheria (DTaP with an efficacy of

70% to 90%;

Compared with older, whole cell pertussis

vaccines, acellular vaccines have fewer

adverse effects and local reactions.

PREVENTION

Erythromycin and other macrolides

effective in preventing disease in

contacts exposed to pertussis.

PREVENTION

Close contact <7y should be given a macrolide antibiotic.

should receive a booster dose of DTaP, unless a

booster dose has been given within the preceding

3 years.

Close contact > 7y prophylactic macrolide antibiotic for 10 to 14 days

NOT the vaccine.

Thank you for your attention