PERTUSSIS(whooping cough)

Chiara Rose M. SalalimaAAPD2ADr. Balacanao

PERTUSSISan acute respiratory tract infection that was described by Sydenham as pertussis, meaning intense cough, it is preferable to whooping cough because most infected individuals do not “whoop.”

ETIOLOGY Bordetella pertussis is the cause of epidemic

pertussis and the usual cause of sporadic pertussis.

Bordetella parapertussis is an occasional cause of sporadic pertussis that contributes significantly to 5% of the total cases of pertussis.

All are gram-negative coccobacilli that are recovered best on Bordet- Gengou media.

EPIDEMIOLOGY Spread occurs by direct contact or droplet

infections during cough. Infants less than one year of age constitute

50-70% of diagnosed cases.

• The disease occurs 3-12 days after exposure to an infected individual• The coughing stage lasts for approximately six weeks before subsiding. In some countries, this disease is called the 100 days' cough or cough of 100 days because of its length.

Period of Period of communicabilitycommunicability

WHAT ARE THE SYMPTOMS OF PERTUSSIS? The "whoop" sound occurs with the forceful

inspiration after a coughing fit.  This sound is uncommon in young infants and adults, but may be more common in children.

The entire illness may last as long as 6 weeks.

The illness occurs in 3 major stages (the catarrhal, paroxysmal, and convalescent stages)

Infants and adults may not show the normal progression of stages

Children (especially infants) may appear perfectly well in between episodes of coughing.

A complete blood count may show a high lymphocyte count.  If the neutrophil count is high and/or fever is present, then other types of infection should be considered.

A chest x-ray may be normal or show mild abnormalities.

Bacterial culture of respiratory secretions is the best test.

CLINICAL MANIFESTATIONS:The incubation period of pertussis has a mean of 7 and a range of 6-20 days.

Classically, divided into:1- Catarrhal, 2- Paroxysmal, and 3- Convalescent stages.

CATARRHAL STAGE The term "catarrh" is derived from

historic Middle English, meaning "to flow."  That is, secretions from the nose and mucous membranes flow, causing nasal congestion and runny nose.

Nasal congestion Runny nose Mild fever Eye redness and excess eye watering

PAROXYSMAL STAGE (2-4WK)

The term "paroxysm" means a sudden, violent burst.  The paroxysms or "fits" of coughing may...

start as a dry, intermittent, annoying cough that increases in intensity and frequency

occur at least once an hour cause the child to turn red, blue, or purple cause the eyes to bulge and water excessively cause significant distress in the child have a "machine-gun" pattern vomiting after coughing

Young infants may have small bursts of cough or no cough before developing...

Gasping Choking Turning red, blue or purple Apnea (episodes of not breathing)

CONVALESCENT CONVALESCENT STAGE (STAGE (≥2 WK≥2 WK))

The coughing fits become less frequent and less intense.  Young infants may develop louder coughing but typically the breathing difficulty improves.

WHAT ARE THE POSSIBLE COMPLICATIONS OF PERTUSSIS?Infants less than 6 months of age are at the highest

risk for complications.  These include: Apnea Ear infections Pneumonia Seizures Encephalopathy (brain damage) Death (approximately 1% of infants less than 2

months of age)

TREATMENTGoals of therapy are to1. limit the number of paroxysms, 2. to observe the severity of the cough, 3. to provide assistance when necessary,4. to maximize nutrition, rest, and

recovery without sequelae

HOW IS PERTUSSIS TREATED?

Hospitalization is common, especially for infants less than 6 months.  Respiratory support such as supplemental oxygen or even mechanical venitlation may be necessary for severe disease. 

All individuals with confirmed (or highly suspected) pertussis should be treated with antibiotics such as erythromycin, azithromycin or clarithromycin.  Note - erythromycin increases the risk of hypertrophic pyloric stenosis in young infants.  Antibiotics reduce the severity of illness and also reduce the spread of the illness.

ANTIBIOTICS

An antimicrobial agent is always given when pertussis is suspected or confirmed primarily to limit the spread of infection and secondarily for possible clinical benefit.

Macrolides are preferred agents.

Resistance has been reported rarely.

Erythromycin [50mg/kg/day] for 14 days may eliminate pertussis organisms from the nasopharynx within 3-4 days, thereby reducing communicability and may abort or eliminate pertussis if given within 14 days, of onset of the disease.

Supportive care : avoidance of factors that provoke attacks of coughing, maintenance of the hydration and nutrition, oxygen if there is distress, gentle suction for viscid secretions.

SHOULD EXPOSED FAMILY MEMBERS BE TREATED?

Yes.  Family members and close contacts of an infected child should be treated with antibiotics to prevent spread of the illness.  This is true even for vaccinated individuals.  Typically 14 days of an antibiotic such as erythromycin is prescribed.  Azithromycin and clarithromycin may be acceptable alternatives.

ISOLATION Patients with suspected pertussis are placed

in respiratory isolation with use of masks by all health care personnel entering the room. Screening for cough should be performed and isolation until 5 days after initiation of macrolide therapy.

Children and staff with pertussis in child-care facilities or schools should be excluded until macrolide prophylaxis has been taken for 5 days.

CAN PERTUSSIS BE PREVENTED? The pertussive vaccine is effective for at

least 5 years.  This helps prevent infection in the age group where pertussis infection is most severe.  The pertussis vaccine is part of the DTaP vaccine (along with tetanus and diphtheria).  The DTaP vaccine should be given in five doses at ages 2 months, 4 months, 6 months, 15 to 18 months, and 4 to 6 years.  A booster dose is recommended at 11 to 12 years of age.