3. Etiology
• B. pertussis is a fastidious, gram-negative coccobacilli that
requires special media for culture
• B. pertussis is transmitted via aerosolized respiratory
droplets.
• Once inhaled it will attached to respiratory mucosal cells
and induce local tissue damage via tracheal cytotoxins,
dermonecrotic toxin, or adneylate cyclase; this destructive
process is responsible for the cough.
• The most notable systemic laboratory manifestation is
lymphocytosis, which is caused by pertussis toxin
• PT may also cause hyperinsulinemia with resultant
hypoglycemia in young infants.
• It is exclusively a human pathogen and is highly contagious
4. Epidemiology
• Extremely contagious, attack rate as 100% in susceptible
individuals exposed to aerosol droplets at close range.
• Neither natural disease nor vaccination provides
complete or lifelong immunity.
• Protection against typical disease begins to wane 3–5 yr
after vaccination and is un measurable after 12 yr need
booster dose of 11-18 years TdaP not DTaP
• Pertussis is the only vaccine-preventable disease for
which universal immunization in the USA is
recommended that continues to be endemic
• After intense exposure, rate of subclinical infection is as
high as 80% in fully immunized or previously infected
children.
6. Clinical Manifestations
Classically divided into 3 stages
• Catarrhal stage (1–2 wk)-after an incubation
period of 3–12 days with congestion and rhinorrhea
accompanied by low-grade fever, sneezing,
lacrimation, and conjunctival effusion.
• Paroxysmal stage (2–6 wk) begins as a dry,
intermittent, irritative hacky cough and evolves into
paroxysmal cough which is the hallmark of pertussis.
Post-tussive emesis
• Convalescent stage (≥2 wk)-the number,
severity, and duration of paroxysms episodes
diminish.
8. …
• The cough can prolong up to three months
• The patient is infectious 2wks to 3 months
after the onset of the illness.
• Most useful diagnostic signs
Paroxysmal cough followed by whoop and vommiting
Subconjuctival hemorage
Young infants may not whoop
9. Infants <3 mo of age
• Do not display classical stages.
• Catarrhal phase lasts only a few days or is unnoticed
• Cough (expiratory grunt) not prominent.
• Whoop infrequently occurs (at the end of a
paroxysm lack stature or muscular strength to create
sudden negative intrathoracic pressure )
• Cyanosis follows a coughing paroxysm, or
• Apnea may be the only symptom
• Paroxysmal and convalescent stages are lengthy.
• Immunized children have foreshortening of all stages
10. Cont…
Atypical presentations:
• Infants :-catarrhal stage very short or absent but
paroxysmal and convalescent stages in young infants are
lengthy
Early symptoms can include feeding difficulties,
tachypnea, and cough.
Paroxysms of cough, during which the infant may develop
gagging, apnea, cyanosis, and bradycardia, may be the
only manifestation and whoop is not a characteristic
The infant can appear well between episodes of coughing.
Paradoxically, in infants, cough and whooping may
become louder and more classic in convalescence
2/20/2023 10
11. Cont…
• In vaccinated children:- all stages are shortened
Severity is lower both the incidence of apnea and cyanosis
are found to be low
• In adolescents: - no distinct stages
A sudden feeling of strangulation followed by
uninterrupted coughs, feeling of suffocation, bursting
headache, diminished awareness, and then a gasping
breath, usually without a whoop
• Post tussive emesis and intermittency of paroxysms
separated by hours of well-being are specific clues
2/20/2023 11
12. Diagnosis
• Any child with predominant complaint of cough,
especially if the following are absent: fever, malaise or
myalgia, exanthem or enanthem, sore throat,
hoarseness, tachypnea, wheezes, and rales
• Clinical case definition of cough of ≥14 days with at
least 1 associated symptom of paroxysms, whoop, or
post-tussive vomiting has a sensitivity of 81%, and
specificity of 58% for culture confirmation
• Older children with cough lasting > 7–10 days and
whose cough is not continuous.
• Infants <3 mo of age with apnea, or cyanosis
13. ..
CBC
• Leukocytosis (15,000–100,000 cells/mm3) with absolute
lymphocytosis is characteristic in the catarrhal stage.
• Eosinophilia is not a manifestation of pertussis
Culture and Fluorescent antibody test -Nasopharyngeal
swabs
CXR
• Perihilar infiltrate (sometimes with a Shaggy heart
border) and variable atelectasis in the majority
• Consolidation suggests secondary bacterial infection.
• Pneumothorax, pneumomediastinum, and air in soft
tissues
• DFA for the toxin not for the bacteria
14. DDx
Adenoviral infections
• Associated features: fever, sore throat, and
conjunctivitis.
Mycoplasma
• Protracted episodic cough
• Usually a history of fever and more continuous
cough as well as frequent finding of rales
Bronchiolotis
Tuberculosis
Foreign body aspiration
15. Complications
• Bronchopneumonia(25% of cases)---The most common
complication, and cause of death in infants
• Apnea or bradycardia ---b/c of vagal stimulation
• Otitis media and sinusitis-----due to pneumococcus
• Convulsions is usually a result of hypoxemia, but
hyponatremia from excessive secretion of antidiuretic
hormone during pneumonia can occur.
• Encephalitis----the toxin of the cellular vaccine
• Retinal, conjunctival, intracerebral and sub subarachnoid
hemorrages---b/c of the increased intrabdomenal pressure
• Rectal prolapse,Umblical hernia
• Reactivation of latent tuberculosis
• Malnutrition
• Pneumothorax, Pneumomediastinum,Interstitial and
Subcutaneous emphysema
• Tetany due to post tussive alkalosis
16. Treatment
Goals
• To limit the number of paroxysms-
Antibiotic
• To maximize nutrition, rest, and recovery
without sequelae
17. Indication for admission
• Infant < 3 months should always be admitted
• Child <6months if sever paroxysmal attack
• With complication
Pneumonia
SAM
Seizure
DHN
Sever
Apenea
Cyanosis
18. Treatment…
• Antibiotics
Macrolides are preferred agents
Azithromycin 10 mg/kg/day in a single dose for 5 days
Erythromycin, 40-50 mg/kg/day in 4 divided doses for
14 days. This doses not shorten the illnes rather
decrease infectiousness
• Isolation
• Chemoprophylaxis
19.
20. Supportive therapy
• Air way management
• Aviod manipulation or any antihistamine
which will exacerbate the whooping
• Oxygen should not be given by catheter
rather by nasal prong to avoid irritation
• If fever > 39 we should give paractamol
15mg/kg PRN
21. Care of Household and Other Close Contacts
• A macrolide agent should be given promptly to all household contacts
and other close contacts, such as those in daycare, regardless of age,
history of immunization, and symptoms.
• Isolation for more than 5 days after initiation of Erthromycin therapy
• In close contacts <7 yr of age who have received fewer than 4 doses of
pertussis-containing vaccines, vaccination should be initiated or
continued to complete the recommended series.
• Children <7 yr of age who received a 3rd dose >6 mo before exposure or
a 4th dose ≥3 yr before exposure should receive a booster dose.
• Individuals ≥9 yr of age should be given a Tdap (adolescent/adult
formulation of tetanus and diphtheria toxoids and acellular pertussis)
booster if they have not previously received Tdap.
• Unmasked health care personnel (HCP) exposed to untreated cases
should be evaluated for post-exposure prophylaxis and follow-up.
22. Prevention
• Immunization with pertussis vaccine during
infancy with periodic reinforcing doses -
Central to the control of pertussis.
• Three (primary) doses of DTaP during the
1st year of life
• In adults or adolescence 11-18 years TdaP
