Diphtheria.PSM,COMMUNITY MEDICINE,MBBS,BPH,MD,MPH,DR NARENDRA KUMAR YADAV

1. Diphtheria
DR NARENDRA KUMAR YADAV
MBBS, MD Community Medicine & Tropical Diseases

2. Diphtheria: Definition, Burden of disease, Epidemiological determinants
of diphtheria, Mode of transmission, Incubation period, Clinical
features, management,Control of diphtheria, DPT Vaccine.

3. DIPHTHERIA:
Diphtheria is an acute infectious disease caused by toxigenic
strains of Corynebacterium diphtheriae.
Corynebacterium: Gram-Positive, non-motile bacteria.

4. Epidemiology:
WORLD:
Rare in developed country
Year 2016: 7,097 cases
Nepal/India:
Endemic disease
Nepal: 774 diphtheria cases were found in 20 years.
India: 5293 Cases including 148 deaths (Year 2017)

5. Epidemiological determinants:
1. Agent factor:
Corynebacterium diphtheriae.
SOURCE OF INFECTION: Carriers(95%) > Cases.
(Q. Carriers are more important as source of infection: 95% of total disease
transmission.)
(Q. Nasal carriers are more dangerous than throat carriers.)
(Q. Immunization does not prevent carrier state.)
2.Host factors: 1- 5 years (M=F)
3.Environmental factors: More common in Winter

6. DIPHTHERIA:
Incubation period: 2-6 days
Mode of transmission:
1. Respiratory Route: Air droplets (main mode)
2. Non-respiratory Routes: Skin (Cuts, ulcers)
Period of communicability: 14 -28 days from onset of disease
Non communicable to others: ≥ 2 Cultures are negative
(Q. A case/carrier may be considered non-communicable when at least 2
cultures from nose and throat, 24 hrs apart, are negative.)

7. Pathogenesis:
The bacteria multiply locally, usually in the throat, and start to
produce powerful exotoxin which is then absorbed into the mucous
membrane, leading to:
Inflammation, congestion, oedema
The formation of a greyish or yellowish membrane (Pseudo
membrane) commonly over the tonsils, pharynx or larynx.
Enlargement of the regional lymph nodes
Signs and symptoms of toxaemia.

8. Types of Diphtheria:
1. Three major clinical types:
Anterior nasal diphtheria
Pharygotonsillar diphtheria
Laryngotracheal diphtheria
2. Other types:
Cutaneous(Skin)
 Conjunctival
Genital(Vulva)

9. Anterior nasal diphtheria:

10. Pharygotonsillar diphtheria:
Bull-neck appearance in diphtheria

11. Laryngotracheal diphtheria:

12. Cutaneous diphtheria:

13. Conjunctival diphtheria:

14. Bull-neck appearance in diphtheria:

15. Clinical features:
Clinical features due to infection:
 Fever
Headache
Nausea, Vomiting
Clinical features due to Pseudo membrane:
Sore throat
Difficulty in swallowing
Difficulty in breathing

16. Prevention and control:
1. Active immunization: DPT
2. Early detection of cases and Carriers
3. Isolation: Cases should be isolated
4. Treatment of cases, carriers and contact.

17. DPT:
Type: Toxoid
Age of administration: 6W, 10W, 14W
Dose: 0.5 ml
Route of administration: i /m
Site of administration:

18. Treatment of cases, carriers and contact:
1. Treatment of cases:
a. Antidiphtheritic horse serum OR Diphtheria Antitoxin (Treatment of choice).
b. Antibiotics: Penicillin G OR Oral Erythromycin (DOC)* 12-14 days
(and Do Serial Culture)
2. Treatment of carriers: Antibiotics (Penicillin OR Oral Erythromycin)* 10days
(and Do Serial Culture)
3. Treatment of contact:
a. Penicillin G OR Oral Erythromycin * 7 days
b. Diphtheria Toxoid

19. SCHICK TEST: An intradermal test to access immunity status of
children against diphtheria:
Type: I/D HYPERSENSITIVITY Skin Test
Dose: 0.2 ml, Schick Toxin in test arm and 0.2 ml
inactivated toxin in opposite arm (Control arm).
Reading: After 96 hr.

20. Interpretation of SCHICK TEST:
Observation: Reading: Interpretation:
TEST ARM: CONTROL ARM:
No reaction No reaction NEGATIVE Immune to diphtheria
Red
flush(ERYTHEMA)
No reaction POSITIVE Susceptible to diphtheria
(Management: Immediate
Immunization)
Red flush fading
by 4th day
Red flush fading
by 4th day
PSEUDOPOSITIVE Hypersensitive and already
immunized.
Red
flush(ERYTHEMA)
Pseudo positive COMBINED Hypersensitive and susceptible to
diphtheria
(Management: Desensitization).

21. Schick Test is replaced by:
 Hemeagglutination Test: Measurement of serum antitoxin level

22. MCQ
Q. True about Diphtheria are all except:
(a) Carriers are more common sources of infection than cases
(b) Incubation period is 2-6 days
(c) 25 Lf of diphtheria toxoid are present per ml in DPT vaccine
(d) Diphtheria is an endemic disease in Nepal and India

23. .
ANS: (c) 25 Lf of diphtheria toxoid are present per ml in DPT vaccine

24. MCQ
Q. Positive Schick test indicates:
(a)Immunity to diphtheria
(b) Susceptibility to diphtheria
(c) Hypersensitivity to diphtheria
(d) Infection with diphtheria

25. .
Ans: (b) Susceptibility to diphtheria

26. Interpretation of SCHICK TEST:
Observation: Reading: Interpretation:
TEST ARM: CONTROL ARM:
No reaction No reaction NEGATIVE Immune to diphtheria
Red
flush(ERYTHEMA)
No reaction POSITIVE Susceptible to diphtheria
(Management: Immediate
Immunization)
Red flush fading
by 4th day
Red flush fading
by 4th day
PSEUDOPOSITIVE Hypersensitive and already
immunized.
Red
flush(ERYTHEMA)
Pseudo positive COMBINED Hypersensitive and susceptible to
diphtheria
(Management: Desensitization).

27. MCQ
Q. Treatment of choice for diphtheria carriers is:
(a) Erythromycin
(b) Tetracycline
(c) Penicillin
(d) DPT

28. .
Ans: (a) Erythromycin

29. MCQ
Q. Schick test does not indicate:
(a) Immunity to diphtheria
(b) Susceptibility to diphtheria
(c) Hypersensitivity to diphtheria
(d) Carrier of diphtheria

30. .
Ans. (d) Carrier of diphtheria

31. Interpretation of SCHICK TEST:
Observation: Reading: Interpretation:
TEST ARM: CONTROL ARM:
No reaction No reaction NEGATIVE Immune to diphtheria
Red
flush(ERYTHEMA)
No reaction POSITIVE Susceptible to diphtheria
(Management: Immediate
Immunization)
Red flush fading
by 4th day
Red flush fading
by 4th day
PSEUDOPOSITIVE Hypersensitive and already
immunized.
Red
flush(ERYTHEMA)
Pseudo positive COMBINED Hypersensitive and susceptible to
diphtheria
(Management: Desensitization).

32. MCQ
Q. Diphtheria carrier are diagnosed by:
(a)Throat culture
(b)(b) Gram’s staining
(c) Albert’s staining
(d) Schick test

33. .
Ans. (a) Throat culture

34. MCQ
Q. A Negative Schick test indicates:
(a) Immunity to Diphtheria
(b) Susceptibility to Diphtheria
(c) Immunity to Pertusis
(d) Immunity to Mumps

35. .
Ans. (a) Immunity to diphtheria

36. Interpretation of SCHICK TEST:
Observation: Reading: Interpretation:
TEST ARM: CONTROL ARM:
No reaction No reaction NEGATIVE Immune to diphtheria
Red
flush(ERYTHEMA)
No reaction POSITIVE Susceptible to diphtheria
(Management: Immediate
Immunization)
Red flush fading
by 4th day
Red flush fading
by 4th day
PSEUDOPOSITIVE Hypersensitive and already
immunized.
Red
flush(ERYTHEMA)
Pseudo positive COMBINED Hypersensitive and susceptible to
diphtheria
(Management: Desensitization).

37. MCQ
Q. A herd immunity of over …….. % is considered necessary to
prevent epidemic spread of diphtheria:
(a) 50%
(b) 55%
(c) 60%
(d) 70%

38. .
Ans. (d) 70%

39. MCQ
Q. Management of non immunized diphtheria contacts include all
except:
(a) Prophylactic penicillin
(b) Single dose of toxoid
(c) Daily throat examination
(d) Daily throat swab culture
(e) Weekly throat swabs examination

40. .
Ans: (b) Single dose of toxoid; (d) Daily throat swab culture

41. The End