PERTUSSIS(Whooping cough)

By; Dr Yusuf ImranDept. of PediatricsJ.N Medical College

AMU (INDIA)

DEFINITION Pertussis is an acute respiratory tract

infection caused by Bordetella pertussis

Characterized by intense spasmodic cough "whoop.“

Sydenham first used the term pertussis (intense cough) in 1670

worldwide prevalence is decreased by active immunization

EPIDEMIOLOGY

Continues to be public health concern even in countries with high immunization coverage

About 1.29 lac cases were reported to WHO globally, in 2010

In India ,marked decline in incidence occurred after launch of UIP ( 1.63 lac cases in 1987 vs only 39,091 cases in 2011; 76% decrease)

MODE OF SPREAD

DROPLETS Highly contagious,almost 100% in

susceptible host(under fives) Undiagnosed adults may be a source when source is not obvious Do not survive in dust for too long

ETIOLOGY. Bordetella pertussis is the sole cause of epidemic

pertussis and usual cause of sporadic pertussis

B. parapertussis is an occasional cause ( fewer than 5% of cases )

These two are exclusive human pathogen (and for some primates)

B. bronchiseptica is common animal pathogen

Pertussoid syndrome : protracted coughing can also be caused by Mycoplasma, parainfluenza or influenza viruses, enteroviruses, RSV & adenoviruses.

PATHOGENESIS. A E R O S O L A C Q U I S I T I O N O F B

P E R T U S S I S

AT T A C H T O R E S P I R AT O RY E P I T H . C E L L S W I T H S U R FA C E F I L A M E N T O U S H E M A G G L U T I N I N ( F H A ) , F I M B R I A E ( T Y P E S 2 A N D 3 ) & P E R T A C T I N

P R O D U C E T R A C H E A L C Y T O T O X I N , A D E N Y L AT E C Y C L A S E A N D P E R T U S S I S T O X I N ( P T ) W H I C H D A M A G E L O C A L E P I T H E L I U M & E X E R T V A R I O U S B I O L O G I C A C T I V I T I E S

CLINICAL MANIFESTATIONS Classically pertussis is divided into :

catarrhal stage- begins after an incubation period of 3-12 days with symptoms of congestion, rhinorrhea , low-grade fever, sneezing, lacrimation, and conjunctivitis (last 1-2wks)

Paroxysmal stage- dry, intermittent, irritative cough characterized by whoop(forceful inspiratory gasp) infrequently occurs in infants <3 mo .Post-tussive emesis is common (lasts for 2-6 wks )

convalescent stage- no. & severity of episodes decreases over next 1-4 weeks

MANAGEMENTGoals of therapy :

Supportive- give oxygen if cyanosed, proper nutrition, rest, hydration & avoid stimulation

salbutamol (albuterol) – nebulization may alleviate symptom(cough suppressants are contraindicated)

Antimicrobial Agents – 1)Erythromycin (40-50 mg/kg/24 hr divided qid)

for 14 days is standard treatment 2)Clarithromycin , azithromycin & co-

trimoxazole are useful alternatives

ISOLATION ,CARE OF CONTACTS &PREVENTION

Patients placed in respiratory isolation for ≥5d

Chemoprophylaxis: Erythromycin for 14 days should be given to all household and other close contacts

Close contacts <7 yr of age who have received less than four doses of pertussis vaccines should have vaccination initiated or continued

Prevention : Universal immunization of children <7 yr of age , beginning in infancy, is central to the control of pertussis

Combination acellular pertussis (DTaP) vaccines are preferred over those containing whole-cell pertussis (DTP) vaccines because of fewer adverse reactions

COMPLICATIONS

The principal complications of pertussis are

Respiratory complications eg a) bronchieactasis

b) secondary infections ( otitis media,pneumonia)

c) atelectasis ,emphysema &pneumothorax

Sequelae of forceful coughing :(raised pressure)

- conjunctival and scleral hemorrhages

- petechiae on the upper body, epistaxis

- hemorrhage in the CNS and retina

-umbilical and inguinal hernias -rectal prolapse

Neurological complications : -seizures( several reasons) -encephalopathy Malnutrition due to persistent vomiting & reduced appetite

Flare up of tuberculosis(decrease CMI)

PERTUSSIS IN YOUNG INFANTS Those <2 mo of age have the highest reported rates

of pertussis-associated complications like- apnea pneumonia(25%) seizures (4%) encephalopathy (1%) and death (1%)

and so hospitalized in 82% case

Apnea, cyanosis, and secondary bacterial pneumonia are events precipitating intubation and ventilation

The need for intensive care and artificial ventilation is usually limited to infants <3 months