PERTUSIS
(WHOOPING COUGH)

•It’s an acute respiratory tract infection.

•It’s the sole cause of epidemic pertusis.   B. pertusis and B. parapertusis are exclusive pathogen of human.

•Majority of the cases occur between July to October. It's highly contagious with attack rate as high as 100%.

•Neither natural infection or vaccination provides complete/life long immunity against re infection or disease.

•Protection against typical disease begin to wane 3 to 5 year after vaccination and is immeasurable after 12 years.Subclinical infection undoubtedly contributes significantly to immunity against disease associated to both vaccine and major infection.

PATHOGENESIS

•B. pertusis produces a tracheal toxin which paralyses the cilia and leads to paroxysmas of coughing as a alternative meaning of removing increase mucus.

•Another toxin pertusis toxin is responsible for characterstics lymphocytosis in uncomplicated whooping cough

CLINICAL MANIFESTATION

•I.P- 3-12 days.

•3 stages- 1. Catarrhal stage.

                    2. Paroxysmal stage.

                    3. Convalescent stage.

Catarrhal stage-

§Congestion and rhinorrhea

§Low grade fever

§Sneezing,Lacrimation and conjunctivae.(?)

§Suffusion

§Unproductive cough 

•Paroxysmal stage- As above symptoms wanes, cough begins. Initially the cough is short,later gathering in speed and duration and ending in a deep respiration and produces a characterstics sound “ whoop” (forceful inspiratory gap)- hallmark of pertusis.

   Post tussive emesis is common in all stages and is a major clue to the diagnosis in adolescent and adults. Post tussive exhaution is universal.

   At the peak on paroxysmal stage, patient may have more than one episode hourly.

•Convalescent stage- As paroxysmal stage fades into convalescent,the number. Severity and duration of episodes diminish.Paradoxically in infants, rich growth and strength, cough becomes louder and more classic in convalescence.

   Immunized children have fore shortening of all stages of pertusis.

   Findings in physical examination generally are uninformative,conjunctival haemorrhages and petechiae in upper body is common.

DIAGNOSIS

•Any individual who has pure or predominant complain of cough, especially if the followings are absent: fever, malaise or myalgia, exanthem, sore throat, hoarsness,tachypnoea, wheeze and rales.

•Whooping cough should be suspected whenever ther is a H/O severe cough lasting more than 2 weeks.This probable whooping cough should be notified and treated as whooping cough if any of the following exist:-

1.Prolonged cough followed by period of apnoea and cyanosis,or in older children,paroxysmas or coughing followed by vomiting or a typical breath intake and whoop or sub conjunctival haemorrhage.

2.Exposure in a suspect cause in previous 3 weeks.

3.Epidemic of whooping cough in area.

4.Lymphocytosis more than 15000/mm3   

DIFERENTIAL DIAGNOSIS

•Adenomal infection- distingishable by associated feature such as fever,sore throat and conjunctivitis.

•Mycoplasma-causes protracted episodes coughing,but pt usually have a history of fever,hedeache and systemic symptoms at the onset of disease as well as frequent findings of rales.

•Chlamydia trachomatis- Staccato cough(breath with every cough). Purulent conjuctivitis, tachypnoea,rales or wheeze.

•RSV- predominant resp tract signs.

INVESTIGATIONS

•CBC-

a. Leukocytosis(15000-1,0000/mm3).due to absolute lymphocytosis is characterstics in late catarrhal and paroxysmal stages.

b.Absolute increase in nutrophils,suggests a different diagnosis or secondary bacterial infection.

c.Eosinophilia is common.

•Chest X-ray-

               Mild abnormal in majority cases, showing peri hilar   

               infiltrate or oedema.(Sometimes with a butterfly 

               appearance) and variable atelactasis.

               Parenchymal consolidation suggests secondary      

               bacterial infections.

•C/S of B. pertusis

•Direct fluroscent Antibody(DFA)      Nasopharyngeal secretions

•PCR

TREATMENT

•Goals-

i.To limit the number of paroxysms.

ii.To observe the severity of cough to prvide assistance when necessary.

iii.To maximize nutrition.

iv.Rest

v.Recovery without sequelae

•Criteria for hospitalizations-

i.Less than 3 month of age.

ii.Infants with severe paroxysms

iii.At any age if significant complication occur.

•O2 therapy

•Antimicrobial therapy-

                      Erythromycin: 40-50 mg/kg/day (max 1gm) 6

                      hourly for 14 days.

                     Azithromycin: 10 mg/kg/day- 5 day.

•Severe cough with paroxysms-

i.Salbutamol

ii.Corticosteriods

iii.Phenobarbitone

•Isolation- Respiratory isolation for at least 5 days after initiation of Erythromycin therapy.

•Care of household and other close contacts:

              Erythromycin: 40-50 mg/kg/24 hours P/O in 4 

              divided dose.-14 days regardless of age and 

              history of immunization.

•Less than 7 year old, who completed last dose of DPT; 6 months or more ago before exposure should receive a booster dose.    


NON-GONOCOCCAL  URETHRITIS:http://nongonococcal.blogspot.com/

 

                          

         

       

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