What Do You Know About Mycobacterium? Trivia Quiz

1. Scrofuloderma is most commonly associated with an underlying infection of what organ system?

Lymph nodes

Spine

Lungs

Gastrointestinal tract

No underlying systemic disease

Scrofuloderma is a skin condition that is typically caused by an underlying infection of the lymph nodes. The infection spreads to the skin, resulting in the formation of nodules or ulcers. This condition is commonly associated with tuberculosis, which is known to affect the lymph nodes. Therefore, the correct answer is lymph nodes.

Explanation

Scrofuloderma is a skin condition that is typically caused by an underlying infection of the lymph nodes. The infection spreads to the skin, resulting in the formation of nodules or ulcers. This condition is commonly associated with tuberculosis, which is known to affect the lymph nodes. Therefore, the correct answer is lymph nodes.

2. A 23-year-old Peace Corps volunteer returns from Africa with an extensive undermined, non-healing ulcerations on the right lower leg. Which of the following infections is the most likely cause of this presentation?

M. marinum

M. kansasii

M. chelonei

M. ulcerans

Leishmania donovani

M. ulcerans is the most likely cause of the extensive undermined, non-healing ulcerations on the right lower leg in this 23-year-old Peace Corps volunteer who returned from Africa. M. ulcerans is a bacterium that causes Buruli ulcer, a chronic skin infection commonly found in tropical and subtropical regions, including parts of Africa. The presentation of extensive ulcerations and non-healing wounds is characteristic of Buruli ulcer, making M. ulcerans the most likely infection in this case.

Explanation

M. ulcerans is the most likely cause of the extensive undermined, non-healing ulcerations on the right lower leg in this 23-year-old Peace Corps volunteer who returned from Africa. M. ulcerans is a bacterium that causes Buruli ulcer, a chronic skin infection commonly found in tropical and subtropical regions, including parts of Africa. The presentation of extensive ulcerations and non-healing wounds is characteristic of Buruli ulcer, making M. ulcerans the most likely infection in this case.

3. Which of the following statements best describes the pathogenesis of scrofuloderma?

Hematogenous spread of M. tuberculosis from a distant site of infection

Autoinoculation of M. tuberculosis from advanced pulmonary tuberculosis

Contiguous spread from an underlying focus of tuberculous lymphadenitis

Primary incoculation of M. tuberculosis in a sensitized host

An cutaneous manifestation of military tuberculosis

Contiguous spread from an underlying focus of tuberculous lymphadenitis is the best description of the pathogenesis of scrofuloderma. Scrofuloderma is a type of cutaneous tuberculosis that occurs when the infection spreads from nearby infected lymph nodes. This is different from other forms of cutaneous tuberculosis, such as primary inoculation or hematogenous spread, which involve different routes of infection. Therefore, the most accurate explanation is that scrofuloderma is caused by the contiguous spread of Mycobacterium tuberculosis from an underlying focus of tuberculous lymphadenitis.

Explanation

Contiguous spread from an underlying focus of tuberculous lymphadenitis is the best description of the pathogenesis of scrofuloderma. Scrofuloderma is a type of cutaneous tuberculosis that occurs when the infection spreads from nearby infected lymph nodes. This is different from other forms of cutaneous tuberculosis, such as primary inoculation or hematogenous spread, which involve different routes of infection. Therefore, the most accurate explanation is that scrofuloderma is caused by the contiguous spread of Mycobacterium tuberculosis from an underlying focus of tuberculous lymphadenitis.

4. This is the term that is used from tuberculosis of the skin and is spread by hematogenous, lymphatic, or contiguous spread. The clinical characteristic is a brownish-red plaque, apple jelly color on diascopy.

Lupus vulgaris

Scrofuloderma

Tuberculous Gumma

Tuberculosis verrucosa cutis

Tuberculosis cutis orificialis

Lupus vulgaris is the correct answer because it is a term used to describe tuberculosis of the skin that is spread through hematogenous, lymphatic, or contiguous spread. The clinical characteristic of lupus vulgaris is a brownish-red plaque with an apple jelly color on diascopy.

Explanation

Lupus vulgaris is the correct answer because it is a term used to describe tuberculosis of the skin that is spread through hematogenous, lymphatic, or contiguous spread. The clinical characteristic of lupus vulgaris is a brownish-red plaque with an apple jelly color on diascopy.

5. Which of the following skin manifestations of tuberculosis infection is a tuberculid?

Erythema induratum of Bazin

Lupus vulgaris

Miliary TB

Scrofuloderma

Tuberculous gumma

Erythema induratum of Bazin is a skin manifestation of tuberculosis infection that is considered a tuberculid. Tuberculids are immunologically mediated skin reactions to tuberculosis infection, rather than direct involvement of the skin by the bacteria. Erythema induratum of Bazin typically presents as painful nodules on the lower legs of young women, and is associated with a positive tuberculin skin test. This manifestation is thought to be a delayed hypersensitivity reaction to mycobacterial antigens, and is not contagious.

Explanation

Erythema induratum of Bazin is a skin manifestation of tuberculosis infection that is considered a tuberculid. Tuberculids are immunologically mediated skin reactions to tuberculosis infection, rather than direct involvement of the skin by the bacteria. Erythema induratum of Bazin typically presents as painful nodules on the lower legs of young women, and is associated with a positive tuberculin skin test. This manifestation is thought to be a delayed hypersensitivity reaction to mycobacterial antigens, and is not contagious.