MCQ Mycobacterium Tuberculosis TB (MTB) (TB)

L1 Question 1: Which of the following is a distinguishing feature of Mycobacterium tuberculosis (MTB) compared to Mycobacterium avium complex (MAC)?

A) Caseating granulomas

B) Non-caseating granulomas

C) Disseminated infection in immunocompromised only

D) Absence of cavitation

Answer:

  • Correct: A) Caseating granulomas
    • “Mycobacterium tuberculosis infection is characterized by the presence of caseating granulomas with central necrosis.” Radiographics
  • Incorrect: B) Non-caseating granulomas
    • More typical of MAC infection.
  • Incorrect: C) Disseminated infection in immunocompromised only
    • MTB can disseminate even in immunocompetent hosts.
  • Incorrect: D) Absence of cavitation
    • MTB often presents with cavitation.

L1 Question 2: What is the primary imaging feature distinguishing MAC from MTB on CT?

A) Centrilobular nodules and tree-in-bud pattern

B) Upper lobe consolidation with cavitation

C) Miliary nodules

D) Large peribronchial masses

Answer:

  • Correct: A) Centrilobular nodules and tree-in-bud pattern
    • “MAC is often associated with small centrilobular nodules and a tree-in-bud pattern, especially in non-smoking elderly females.” Radiopaedia
  • Incorrect: B) Upper lobe consolidation with cavitation
    • More characteristic of MTB.
  • Incorrect: C) Miliary nodules
    • Can be seen in both but not specific to MAC.
  • Incorrect: D) Large peribronchial masses
    • Uncommon for both infections.

L1 Question 3: Which test is specific for diagnosing latent TB infection?

A) Sputum AFB smear

B) Interferon-gamma release assay (IGRA)

C) Chest X-ray

D) NAAT for MTB

Answer:

  • Correct: B) Interferon-gamma release assay (IGRA)
    • “IGRAs measure the release of interferon-gamma in response to MTB antigens, useful for latent TB diagnosis.” CDC
  • Incorrect: A) Sputum AFB smear
    • Used for diagnosing active TB.
  • Incorrect: C) Chest X-ray
    • Non-specific for latent TB.
  • Incorrect: D) NAAT for MTB
    • Confirms active infection.

L2 Question 4: Which of the following statements is true about Mycobacterium avium-intracellulare (MAI)?

A) Primarily affects immunocompetent hosts

B) Typically causes cavitation

C) Associated with bronchiectasis and nodular opacities

D) Responds to standard anti-TB treatment

Answer:

  • Correct: C) Associated with bronchiectasis and nodular opacities
    • “MAI commonly presents with bronchiectasis and nodular opacities, particularly in elderly non-smoking females.” Radiographics
  • Incorrect: A) Primarily affects immunocompetent hosts
    • MAI more commonly affects immunocompromised individuals.
  • Incorrect: B) Typically causes cavitation
    • Cavitation is uncommon in MAI.
  • Incorrect: D) Responds to standard anti-TB treatment
    • Requires macrolide-based therapy.

L2 Question 5: What is a distinguishing radiologic feature of active MTB on CXR?

A) Diffuse ground-glass opacities

B) Cavitary lesions in the upper lobes

C) Tree-in-bud opacities in the lower lobes

D) Bilateral pleural effusions

Answer:

  • Correct: B) Cavitary lesions in the upper lobes
    • “Upper lobe cavitary lesions are a hallmark feature of post-primary TB.” Radiopaedia
  • Incorrect: A) Diffuse ground-glass opacities
    • Not typical for MTB.
  • Incorrect: C) Tree-in-bud opacities in the lower lobes
    • Seen more commonly in MAC.
  • Incorrect: D) Bilateral pleural effusions
    • Can occur but non-specific.

L2 Question 6: Which of the following findings is characteristic of miliary tuberculosis?

A) Micronodules diffusely distributed throughout both lungs

B) Single upper lobe cavitary lesion

C) Tree-in-bud nodularity

D) Hilar lymphadenopathy only

Answer:

  • Correct: A) Micronodules diffusely distributed throughout both lungs
    • “Miliary tuberculosis presents with numerous tiny nodules scattered throughout the lungs, indicative of hematogenous spread.” Radiopaedia

L2 Question 7: Can bovine tuberculosis cause pulmonary disease in humans?

A) Yes, primarily through direct inhalation

B) Yes, often through unpasteurized dairy products

C) No, it only affects animals

D) No, it causes extrapulmonary disease only

Answer:

  • Correct: B) Yes, often through unpasteurized dairy products
    • “Bovine tuberculosis, caused by Mycobacterium bovis, can lead to pulmonary disease in humans through consumption of unpasteurized dairy products and less commonly via inhalation.” CDC

L2 Question 8: Which of the following is a known manifestation of disseminated tuberculosis involving the liver capsule?

A) Hepatic abscess formation

B) Granulomatous hepatitis with capsular enhancement

C) Simple hepatic cysts

D) Fatty liver changes

Answer:

  • Correct: B) Granulomatous hepatitis with capsular enhancement
    • “Disseminated tuberculosis can involve the liver, often presenting as granulomatous hepatitis with capsular enhancement on imaging.” Radiopaedia

L2 Question 9: What does cicatricial atelectasis signify in the context of latent tuberculosis?

A) Collapse of lung tissue due to infection reactivation

B) Fibrotic contraction leading to volume loss

C) Air trapping with hyperinflation

D) Alveolar overdistension without scarring

Answer:

  • Correct: B) Fibrotic contraction leading to volume loss
    • “Cicatricial atelectasis refers to volume loss and distortion of lung architecture due to fibrotic contraction, commonly seen in healed TB lesions.” Radiopaedia

 

L2 Question 10: Which of the following is the most specific imaging feature for latent tuberculosis?

A) Upper lobe cavitation

B) Fibrotic scars with volume loss

C) Centrilobular nodules

D) Miliary nodules

Answer:

  • Correct: B) Fibrotic scars with volume loss
    • “Fibrotic scars with volume loss, particularly in the upper lobes, are characteristic of latent TB, representing healed primary infection.” Radiopaedia
  • Incorrect: A) Upper lobe cavitation
    • More typical of active TB.
  • Incorrect: C) Centrilobular nodules
    • More commonly seen in MAC.
  • Incorrect: D) Miliary nodules
    • Typically associated with disseminated active TB rather than latent TB.