Pertussis (Whooping Cough)

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Pertussis (Whooping Cough)

• Dr. Harivansh Chopra,
• DCH, MD
• Professor,
• Department of Community Medicine,
• LLRM Medical College,
• Meerut.
• harichop_at_gmail.com

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Objectives

1. To study the epidemiology of Pertussis.
2. To study prevention and treatment of Pertussis.

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Pertussis

1. Syadenham first used the term Pertussis
   (intense cough) in1960.
2. It is preferable to the term whooping cough
   since most infected individuals do not whoop.

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EPIDEMIOLOGY

1. Worldwide distribution.
2. Global burden in terms of DALYs lost was 12.95
   million in 2002, and 2.95 lakh died during the
   same year.

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EPIDEMIOLOGY

1. Pertussis is endemic with epidemic cycles every 2
   3 years after accumulation of susceptible
   cohorts.

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India Decline of Pertussis
83.7
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EPIDEMIOLOGY

1. Majority of cases occur from July through
   October.

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EPIDEMIOLOGY

1. Extremely contagious, with attack rate as high as
   100 in susceptible individuals exposed to
   aerosol droplets at close range.

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EPIDEMIOLOGY

1. Sub clinical infection is 50 in fully immunized
   and naturally immune individual.

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Agent Factor

1. Agent is Bacillus pertussis in majority of cases.
2. In 5 cases Bacillus parapertussis.
3. Bacillus pertussis does not survives for
   prolonged periods in the environment

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Source of Infection

• A case of pertussis, which may be mild, missed or
  unrecognized.
• Chronic carriage by humans is not documented.

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Infective Material

• Nasopharyngeal and bronchial secretions
  Droplet infection and Direct contact.
• Freshly contaminated fomites.

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Infective Period

• A week after exposure to about 3 weeks after the
  onset of the paroxysmal stage.

Secondary Attack rate is 90.
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Incubation Period

• Ranges from 7 14 days.

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Host Factor Age

• Primarily a disease of infants and pre-school
  children.
• Higher incidence found below five years of age.

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Host Factor Age

• Median age of infection
• Developing countries 20-30 months.
• Developed countries 50 months.
• Infants lt 6 months of age have highest mortality.

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Host Factor Sex

• Female children show higher incidence and
  mortality.

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Host Factors - Immunity

1. Infants are susceptible to infection from birth
   because there is no protection from maternal
   antibodies.
2. Recovery from Pertussis and Adequate Immunisation
   both lead to immunity.

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Host Factors - Immunity

1. Neither natural disease nor vaccination provides
   complete or lifelong immunity against reinfection
   or disease.
2. Protection begins to wane 3 5 yrs after
   vaccination unmeasurable after 12 yrs.
3. Subclinical reinfection contributes significantly
   to immunity against disease, ascribed to vaccine
   or prior infection.

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CLINICAL MANIFESTATIONS
Catarrhal Stage
Paroxysmal Stage
Convalescent Stage
Due to long duration of the disease, Pertussis is
also known as 100 day cough.
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Catarrhal Stage

1. The stage lasts for 7-14 days.
2. It is the most infectious period.
3. Features
4. Low-grade fever.
5. Sneezing.
6. Lacrimation.
7. Conjunctival suffusion.

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Catarrhal Stage

• Cough
• Not paroxysmal in early stages, but more annoying
  and frequent at night.
• Does not improve with passage of time, unlike
  upper respiratory tract infections.
• Paroxysmal nature of cough can be suspected
  towards the later part of this phase.

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Paroxysmal Phase

1. This stage lasts for 2-4 weeks
2. Cough
3. Initially dry, intermittent, irritative hack.
4. Evolves into inexorable paroxysms.

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Paroxysmal Phase

1. The bout of cough terminates with along drawn out
   inspiratory crowing sound or whoop.

What is cough?
Cough is a forced expiratory effort against
closed glottis.
Hear cough, click here
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Whoop

• The whoop is produced by the air rushing in
  during inspiration through the half open glottis.

Hear whoop, click here
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Paroxysmal Phase

• The paroxysms of cough may occur every hour, or
  even frequently, and may terminate by vomiting.

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Paroxysmal Phase

1. The child may appear chocked ,is unable to
   breath, looks anxious and has suffused face.

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Paroxysmal Phase

1. The whoop may not always present in infants, who
   present with apneic or cyanotic spells.

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Infants lt3 mo do not display classical stages.
After the most insignificant startle from a
draught, light, sound, sucking, or stretching, a
well-appearing young infant begins to choke,
gasp, and flail extremities, with face reddened.
Cough (expiratory grunt) may not be prominent.
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Whoop (forceful inspiratory gasp) infrequently
occurs in infants lt3 mo of age who are exhausted
or lack muscular strength to create sudden
negative intrathoracic pressure
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A well-appearing, playful toddler with similarly
insignificant provocation suddenly expresses an
anxious aura and may clutch a parent or
comforting adult before beginning a machine-gun
burst of uninterrupted coughs, chin and chest
held forward, tongue protruding maximally, eyes
bulging and watering, face purple, until coughing
ceases and a loud whoop follows as inspired air
traverses the still partially closed airway.
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Whoop

• The whoop is produced by the air rushing in
  during inspiration through the half open glottis.

Hear whoop, click here
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Adults describe 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
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Convalescent Phase

1. During convalescence, the interval between the
   paroxysms of cough increases and severity of
   episode decreases gradually.
2. Paradoxically, in infants, coughs and whoop may
   become louder and more classic in convalescence.

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Clinical Manifestations Additional notes

1. Immunized children have foreshortening of all
   stages of pertussis.
2. Adults have no distinct stages.

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Clinical Manifestations Additional notes

1. In infants lt 3months the catarrhal stage is
   usually a few days or not recognized at all when
   apnea chocking or gasping cough herald the onset
   of disease.

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MCQs

1. Which of the following is not true about
   Pertussis
2. The other name is Whooping cough.
3. The other name is Hundred day cough.
4. Everyone suffering from it must have whoop.
5. It is endemic with superimposed epidemic cycles
   every 2-3 years.

Ans. 3.
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Diagnosis Clinical

1. High suspicion index in individual having pure or
   predominant complaint of cough f/b vomitting, and
   Absent
2. Fever.
3. Malaise / Myalgia.
4. Exanthem / Enanthem.
5. Sore throat, Hoarseness.
6. Tachypnoea.
7. Wheezes, Rales.

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Diagnosis Clinical

1. In infants lt 3 months of age, Apnea or Cyanosis
   (before appreciation of cough) is the clue
   occasionally cause of Sudden Infant Death.

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Diagnosis Blood picture

1. Leukocytosis 15,000-100,000cells/mm3.
2. Absolute lymphocytosis.
3. Absolute increase in neutrophils suggests a
   differential diagnosis or secondary bacterial
   infection.

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Diagnosis Chest radiograph

1. Only mildly abnormal perihilar infiltrate or
   edema (sometimes butterfly appearance), and
   variable atelectasis.
2. Parenchymal consolidation suggests secondary
   bacterial infection.
3. Occasional Pneumothorax, Pneumomediastinum, and
   air in soft tissues.

Pertussis pneumonia with hyperaeration (air
trapping)
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Diagnosis Bacteriological testing

1. Isolation of Bacillus pertussis is the gold
   standard in diagnosis.
2. Positive in catarrhal and paroxysmal stage.

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Diagnosis Serology

1. Tests for detection of antibodies in acute and
   convalescent samples are most sensitive tests in
   immunised individuals.
2. Antibody to PT raised gt2S.D. indicates recent
   infection.
3. Useful epidemiologically.

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Differential Diagnosis

1. Adenoviral infections distinguishable by
   presence of fever, sore throat, and
   conjunctivitis.
2. Mycoplasma distinguishable by history of fever,
   headache, systemic symptoms frequent rales on
   chest auscultation.

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Differential Diagnosis

1. Afebrile pneumonia (Chlamydia trachomatis)
   distinguishable by staccato cough (i.e. breath
   with every cough), purulent conjunctivitis,
   tachypnea, rales.
2. Afebrile pneumonia (RSV) distinguishable by
   lower respiratory tract signs.

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MCQs

• Which of the following is diagnostic of pertusis
• Leucocytosis with absolute lymphocytosis.
• Leucocytosis with relative lymphocytosis.
• Leucocytosis with neutropenia.
• Leucocytosis with eosinopenia.

Ans. 1.
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Complications

• Apnea.
• Secondary infections
• Otitis media.
• Pneumonia.
• Flaring up of existing TB infection.
• Malnutrition.

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Complications
Physical sequel of forceful coughing

• Conjuctival and Scleral hemorrhage.
• Petechiae in upper body.

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Complications
Physical sequel of forceful coughing

1. Epistaxis.
2. Hemorrhage in CNS and Retina.

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Complications
Physical sequel of forceful coughing

• Pneunomothorax.
• Subcutaneous emphysema.
• Umbilical and inguinal hernia.

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Treatment

1. Antibiotics are useful only in the catarrhal
   stage.
2. Once the child goes in paroxysmal stage it is
   very difficult to abort the attack.

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Treatment

1. Erythromycin 40-50 mg/kg/day in 4 divided doses X
   14days. (Maximum 2 gm / 24 hrs.)
2. Respiratory Isolation for 5 days after start of
   Erythromycin therapy.

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Alternative drugs

1. Clarithromycin 15-20 mg/kg/day in 2 div doses X 7
   days. (Maximum 1 gm/24 hrs.)
2. Azithromycin 10 mg/kg/day once daily X 5 days.

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Alternative drugs

1. Ampicillin, Rifampicin and Cotrimoxazole are
   modestly active against pertussis.
2. The 1st and 2nd generation Cephalosporins are not
   active against pertussis.

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MCQs

• The attack of pertussis can be aborted with the
  help of antibiotics only if the is treated
• In catarrhal stage.
• In paroxysmal stage.
• In convalescent stage.
• In all the above stages.

Ans. 1.
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MCQs

• The drug of choice for the treatment of Pertusis
  its dose is
• Erythromycin 40-50 mg/kg/day
• Cephalexin 50-100 mg/kg/day
• Cotrimoxazole 5-8 mg/kg/day
• Tetracyclin 20-40 mg/kg/day

Ans. 1.
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Care of Household and Close Contacts
Chemoprophylaxis

• Erythromycin 40-50 mg/kg/day in 4 divided doses
  X 14 days regardless of age, history of
  immuinisation, and symptoms.

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Care of Household and Close Contacts
Immunisation
Situation for contact lt 7 years Recommendation
Not vaccinated against pertussis Initiate vaccination
Partially vaccinated against pertussis Complete the recommended schedule
Received 3rd dose gt 6 mths. back Booster dose
Received 4th dose 3 years back Booster dose
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PREVENTION
V A C C I N E S
Purified Acellular Vaccine
Whole Cell Vaccine
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Whole cell vaccine (DTP)

1. Developed in late 1940s.
2. Bacteria killed by heat or formalin.
3. Controversial because of local and systemic side
   effects
4. Redness, Pain, Swelling.
5. Fever (30-70).

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Whole cell vaccine (DTP)

• National Childhood Encephalopathy Study (Britain)
  
• Infantile Spasms.
• Sudden Infant Death Syndrome (SIDS).
• Efficacy
• Three doses.
• 80 - 90 effective.

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Purified acellular vaccine (DTaP)

• Introduced in 1981 by Japan.
• Contains subcomponents of bacteria
• Filamentous Hemagglutinin (Fha).
• Pertussis Toxin (PT).

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Purified acellular vaccine (DTaP)

• Efficacy
• Two doses.
• 70 protection against culture confirmed
  infection.
• 80 protection against severe whopping cough.

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DTP Vaccine

1. Content (BE ltd.)
2. Diptheria toxoid 20Lf to 30Lf.
3. Pertussis 4 IU.
4. Tetanus toxoid 5Lf to 25Lf.
5. Dose 0.5 ml.
6. Route Deep intramuscular.
7. Recommended site Antero-lateral part of thigh.

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Vaccination Schedule

• Immunization Policy
• 3 DPT doses during first year of life.
• EPI recommendation 6, 10, 14 weeks.
• Booster Policy
• 4th DPT vaccine at 12 to 24 months.
• 5th DPT vaccine used by some countries (In
  India, given 3 years after 4th dose).

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Contraindications to vaccination

1. Personal or strong family history of epilepsy,
   convulsions or similar CNS disorders.
2. Any febrile upset until fully recovered.
3. Reaction to one of the previously given triple
   vaccines.

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MCQs

• What is the correct composition of DPT vaccine
• D 40Lf P 4 IU T 5Lf to 25Lf.
• D 20Lf to 30Lf P 10 IU T 5Lf to 25Lf.
• D 20Lf to 30Lf P 4 IU T 5Lf to 25Lf.
• D 20Lf to 30Lf P 4 IU T 25Lf.

Ans. 3.
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Diphtheria toxoid Tetanus toxoid Pertussis
vaccine Diphtheria toxoid 25 Lf, tetanus toxoid
10 Lf, purified Bordetella pertussis antigens
(pertussis toxoid 25 mcg, filamentous
haemagglutinin 25 mcg, 69 kDA outer membrane
protein 8 mcg) per 0.5 mL aluminium hydroxide
(adsorbant),
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Dose 0.5 mL IMI. Primary course 3 doses at 2,
4 and 6 months, then 4th dose at 18 months, 5th
dose at 4-5 years
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Conclusions

1. Pertussis is a vaccine preventable disease caused
   by Bacillus pertussis.
2. It is characterised by intensive cough and whoop,
   and absence of other systemic features.
3. Highly contagious disease prophylaxis of all
   contacts recommended.

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TABLE 3 Composition of DPT vaccines TABLE 3 Composition of DPT vaccines TABLE 3 Composition of DPT vaccines
Contents Glaxo (per 0.5ml) Kasauli
Diphtheria toxoid Tetanus toxoid B. pertussis (millions) AI. phosphate Thiomersal, B.P. 25Lf 5Lf 20 000 2.5 mg 0.01 30 Lf 10 Lf 32 000 3.0 mg 0.01