Pertussis is an acute infection of the respiratory tract caused by B pertussis which is transmitted by respiratory droplets. 

-It is most severe in the very young under the of two years 

-Neither disease nor immunization provides last immunity to pertussis; so there is no long term immunity. 

-adults are an important reservoir of the disease and facilitate its spread

-the bacteria attaches directly to respiratory cilia without invading the tissues

-it releases pertussis toxin which disrupts cell functions locally and systemically

Symptoms & Signs 

-The symptoms last about 6 weeks 

-they are characterized by three phases: the catarrhal phase, the paroxysmal phase, and the convalescent phase. 

The Catarrhal stage: insidious onset, lacrimation, sneezing, coryza, anorexia, malaise, a hacking night cough that becomes diurnal

The Paroxysmal stage: Bursts of rapid, consecutive coughs followed by whoops (deep, high-pitched inspirations) 

The Convalescent stage: decrease in the frequency and severity of paroxysms of cough 

Diagnosis 

Labs: elevated WBC, lymphocytosis 

Culture: nasopharyngeal specimen obtained;  it is slow growing and requires a special selective medium for growth

Imaging: CXR may show thickened bronchi; ‘shaggy’ heart border 

Treatment 

Macrolide antibiotics: Erythromycin, azithromycin, clarithromycin

Allergy to macrolides:  trimethoprim-sulfamethoxazole

Azithromycin use in infants less than 1 month old: risk of pyloric stenosis 

Prevention

All infants: DTaP

Adults of all ages: Tdap

Pregnant women: A dose between 27 and 36 weeks of gestation 

Q.What is the most communicable phase of pertussis? Catarrhal phase 

Q.What is the most serious complication of pertussis? Bronchopneumonia due to superinfection