Diphtheria MCQ Quiz | Infectious Diseases

Welcome to this specialized quiz on Diphtheria, designed for MBBS students preparing for their infectious diseases module. This quiz covers the essential aspects of Corynebacterium diphtheriae, from its microbiology and pathophysiology, including the mechanism of its potent exotoxin, to its diverse clinical presentations like pharyngeal and cutaneous diphtheria. You will be tested on key diagnostic methods such as culture on specific media and the Elek’s test, as well as critical management principles, emphasizing the timely administration of diphtheria antitoxin and appropriate antibiotic therapy. The quiz also touches upon preventive measures, focusing on the toxoid vaccine and public health strategies. After submitting your answers, you can review your score and download all questions with the correct answers in a PDF format for your revision. Good luck!

1. The causative agent of diphtheria, Corynebacterium diphtheriae, is best described as a:

2. The virulence of C. diphtheriae is primarily attributed to the production of an exotoxin. This toxin production is a result of:

3. The mechanism of action of diphtheria toxin involves the inhibition of protein synthesis in eukaryotic cells by:

4. A hallmark clinical sign of pharyngeal diphtheria is the presence of a:

5. The “bull neck” appearance in severe diphtheria is caused by:

6. The most common and serious systemic complication of diphtheria is:

7. Which special culture medium is commonly used to isolate C. diphtheriae, where it produces characteristic gray-to-black colonies?

8. The in-vitro test used to confirm toxigenicity of a C. diphtheriae isolate is the:

9. What is the most crucial and immediate step in the management of a patient with suspected respiratory diphtheria?

10. The diphtheria vaccine is a type of:

11. Neurological complications of diphtheria typically manifest as which of the following, usually starting with local paralysis?

12. The Schick test is used to determine:

13. The primary role of antibiotics in treating diphtheria is to:

14. Cutaneous diphtheria typically presents as:

15. The ‘D’ component in the DTaP vaccine stands for:

16. The most life-threatening aspect of laryngeal diphtheria is:

17. Which of the following is an appropriate post-exposure prophylaxis for an asymptomatic, unimmunized close contact of a diphtheria case?

18. The diphtheria toxin consists of two fragments, A and B. What is the function of the B fragment?

19. In diphtheria-associated myocarditis, which of the following ECG findings is most indicative of a poor prognosis?

20. The microscopic appearance of C. diphtheriae showing club-shaped rods arranged in V- or L-shaped patterns is often described as:

21. Natural infection with C. diphtheriae always confers lifelong immunity.

22. Which of the following is NOT a component of the diphtheritic pseudomembrane?

23. In an Elek’s test, a positive result for a toxigenic strain is indicated by:

24. The primary mode of transmission for respiratory diphtheria is:

25. A patient who has recovered from clinical diphtheria should be managed with which of the following regarding their immunization status?