Pertussis (Whooping Cough)

1. Pertussis (Whooping Cough) Dr. Harivansh Chopra, DCH, MD Professor, Department of Community Medicine, LLRM Medical College, Meerut. harichop@gmail.com

2. Objectives • To study the epidemiology of Pertussis. • To study prevention and treatment of Pertussis. DR HARIVANSH CHOPRA

3. Pertussis • Syadenham first used the term “Pertussis” (intense cough) in1960. • It is preferable to the term “whooping cough” since most infected individuals do not whoop. DR HARIVANSH CHOPRA

4. EPIDEMIOLOGY • Worldwide distribution. • Global burden in terms of DALYs lost was 12.95 million in 2002, and 2.95 lakh died during the same year. DR HARIVANSH CHOPRA

5. EPIDEMIOLOGY • Pertussis is endemic with epidemic cycles every 2 – 3 years after accumulation of susceptible cohorts. DR HARIVANSH CHOPRA

6. India – Decline of Pertussis 83.7% DR HARIVANSH CHOPRA

7. EPIDEMIOLOGY • Majority of cases occur from July through October. DR HARIVANSH CHOPRA

8. EPIDEMIOLOGY • Extremely contagious, with attack rate as high as 100% in susceptible individuals exposed to aerosol droplets at close range. DR HARIVANSH CHOPRA

9. EPIDEMIOLOGY • Sub clinical infection is 50% in fully immunized and naturally immune individual. DR HARIVANSH CHOPRA

10. Agent is Bacillus pertussis in majority of cases. In 5% cases Bacillus parapertussis. Bacillus pertussis does not survives for prolonged periods in the environment Agent Factor DR HARIVANSH CHOPRA

11. Source of Infection • A case of pertussis, which may be mild, missed or unrecognized. • Chronic carriage by humans is not documented. DR HARIVANSH CHOPRA

12. Infective Material • Nasopharyngeal and bronchial secretions – Droplet infection and Direct contact. • Freshly contaminated fomites. DR HARIVANSH CHOPRA

13. Infective Period A week after exposure to about 3 weeks after the onset of the paroxysmal stage. Secondary Attack rate is 90%. DR HARIVANSH CHOPRA

14. Incubation Period Ranges from 7 – 14 days. DR HARIVANSH CHOPRA

15. Host Factor – Age • Primarily a disease of infants and pre-school children. • Higher incidence found below five years of age. DR HARIVANSH CHOPRA

16. Host Factor – Age • Median age of infection : • Developing countries – 20-30 months. • Developed countries – 50 months. • Infants < 6 months of age have highest mortality. DR HARIVANSH CHOPRA

17. Host Factor – Sex Female children show higher incidence and mortality. DR HARIVANSH CHOPRA

18. Host Factors - Immunity • Infants are susceptible to infection from birth because there is no protection from maternal antibodies. • Recovery from Pertussis and Adequate Immunisation both lead to immunity. DR HARIVANSH CHOPRA

19. Host Factors - Immunity • Neither natural disease nor vaccination provides complete or lifelong immunity against reinfection or disease. • Protection begins to wane 3 – 5 yrs after vaccination; unmeasurable after 12 yrs. • Subclinical reinfection contributes significantly to immunity against disease, ascribed to vaccine or prior infection. DR HARIVANSH CHOPRA

20. CLINICAL MANIFESTATIONS Catarrhal Stage Paroxysmal Stage Convalescent Stage Due to long duration of the disease, Pertussis is also known as “100 day cough”. DR HARIVANSH CHOPRA

21. Catarrhal Stage • The stage lasts for 7-14 days. • It is the most infectious period. • Features: • Low-grade fever. • Sneezing. • Lacrimation. • Conjunctival suffusion. DR HARIVANSH CHOPRA

22. 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. DR HARIVANSH CHOPRA

23. Paroxysmal Phase • This stage lasts for 2-4 weeks • Cough: • Initially dry, intermittent, irritative hack. • Evolves into inexorable paroxysms. DR HARIVANSH CHOPRA

24. Paroxysmal Phase • 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. DR HARIVANSH CHOPRA Hear cough, click here

25. Whoop The whoop is produced by the air rushing in during inspiration through the half open glottis. DR HARIVANSH CHOPRA Hear whoop, click here

26. Paroxysmal Phase • The paroxysms of cough may occur every hour, or even frequently, and may terminate by vomiting. DR HARIVANSH CHOPRA

27. Paroxysmal Phase • The child may appear chocked ,is unable to breath, looks anxious and has suffused face. DR HARIVANSH CHOPRA

28. Paroxysmal Phase • The whoop may not always present in infants, who present with apneic or cyanotic spells. DR HARIVANSH CHOPRA

29. Infants <3 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. DR HARIVANSH CHOPRA

30. Whoop (forceful inspiratory gasp) infrequently occurs in infants <3 mo of age who are exhausted or lack muscular strength to create sudden negative intrathoracic pressure DR HARIVANSH CHOPRA

31. 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. DR HARIVANSH CHOPRA

32. Whoop The whoop is produced by the air rushing in during inspiration through the half open glottis. DR HARIVANSH CHOPRA Hear whoop, click here

33. 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 DR HARIVANSH CHOPRA

34. Convalescent Phase • During convalescence, the interval between the paroxysms of cough increases and severity of episode decreases gradually. • Paradoxically, in infants, coughs and whoop may become louder and more classic in convalescence. DR HARIVANSH CHOPRA

35. Clinical Manifestations – Additional notes • Immunized children have foreshortening of all stages of pertussis. • Adults have no distinct stages. DR HARIVANSH CHOPRA

36. Clinical Manifestations – Additional notes • In infants < 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. DR HARIVANSH CHOPRA

37. MCQs • Which of the following is not true about Pertussis – • The other name is “Whooping cough”. • The other name is “Hundred day cough”. • Everyone suffering from it must have whoop. • It is endemic with superimposed epidemic cycles every 2-3 years. Ans. – 3. DR HARIVANSH CHOPRA

38. Diagnosis – Clinical • High suspicion index in individual having pure or predominant complaint of cough f/b vomitting, and Absent: • Fever. • Malaise / Myalgia. • Exanthem / Enanthem. • Sore throat, Hoarseness. • Tachypnoea. • Wheezes, Rales. DR HARIVANSH CHOPRA

39. Diagnosis – Clinical • In infants < 3 months of age, Apnea or Cyanosis (before appreciation of cough) is the clue – occasionally cause of Sudden Infant Death. DR HARIVANSH CHOPRA

40. Diagnosis – Blood picture • Leukocytosis – 15,000-100,000cells/mm3. • Absolute lymphocytosis. • Absolute increase in neutrophils suggests a differential diagnosis or secondary bacterial infection. DR HARIVANSH CHOPRA

41. Diagnosis – Chest radiograph • Only mildly abnormal – perihilar infiltrate or edema (sometimes butterfly appearance), and variable atelectasis. • Parenchymal consolidation suggests secondary bacterial infection. • Occasional Pneumothorax, Pneumomediastinum, and air in soft tissues. Pertussis pneumonia with hyperaeration (air trapping) DR HARIVANSH CHOPRA

42. Diagnosis – Bacteriological testing • Isolation of Bacillus pertussis is the gold standard in diagnosis. • Positive in catarrhal and paroxysmal stage. DR HARIVANSH CHOPRA

43. Diagnosis – Serology • Tests for detection of antibodies in acute and convalescent samples are most sensitive tests in immunised individuals. • Antibody to PT raised >2S.D. indicates recent infection. • Useful epidemiologically. DR HARIVANSH CHOPRA

44. Differential Diagnosis • Adenoviral infections – distinguishable by presence of fever, sore throat, and conjunctivitis. • Mycoplasma – distinguishable by history of fever, headache, & systemic symptoms; frequent rales on chest auscultation. DR HARIVANSH CHOPRA

45. Differential Diagnosis • Afebrile pneumonia (Chlamydia trachomatis) – distinguishable by staccato cough (i.e. breath with every cough), purulent conjunctivitis, tachypnea, rales. • Afebrile pneumonia (RSV) – distinguishable by lower respiratory tract signs. DR HARIVANSH CHOPRA

46. 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. DR HARIVANSH CHOPRA

47. Complications • Apnea. • Secondary infections : • Otitis media. • Pneumonia. • Flaring up of existing TB infection. • Malnutrition. DR HARIVANSH CHOPRA

48. Complications – Physical sequel of forceful coughing • Conjuctival and Scleral hemorrhage. • Petechiae in upper body. DR HARIVANSH CHOPRA

49. Complications – Physical sequel of forceful coughing • Epistaxis. • Hemorrhage in CNS and Retina. DR HARIVANSH CHOPRA

50. Complications – Physical sequel of forceful coughing • Pneunomothorax. • Subcutaneous emphysema. • Umbilical and inguinal hernia. DR HARIVANSH CHOPRA