John Dough

John Dough has come to your clinic because he has been bothered by a cough for the last several months. He has no other complaints except fatigue, and has not been sick for at least a year. He is a 35-year-old white man. He used to work as a baker's assistant, but problems with alcohol caused him to lose his job as well as his family, and now he lives in and out of homeless shelters. He tells you that he feels somewhat warm, so thinks he has a fever, but has not had access to a thermometer to take his temperature. At night he gets especially hot, and sometimes wakes up in a sweat. You note that he is somewhat thin and ask him if he has always been so. He replies that he hasn't kept very good track of his weight, but that his clothes seem to be looser than they used to be so maybe he has lost some weight.

Question 1 - Single Best Answer

A large number of both infectious and non-infectious causes can be responsible for a chronic cough that has not been preceded by an acute illness. Which of the following would you think are MOST likely?   Bugs Database

A) Legionella pneumophila, Streptococcus pneumoniae, Mycobacterium tuberculosis
B) Chlamydia pneumoniae, Mycoplasma pneumoniae, Klebsiella pneumoniae
C) Mycobacterium tuberculosis, Mycoplasma pneumoniae, Bordetella pertussis
D) Mycoplasma pneumonia, Influenza virus, Rhodococcus equi
E) Mycobacterium tuberculosis, Rhodococcus equi, Actinomyces israeli

While he is talking to you, he has a short coughing spell and you note that he has coughed up some blood. You also note that he is dyspnoeic at rest.

Question 2 - Single Best Answer

Which organism is most likely to cause frankly bloody sputum?   Bugs Database

A) Streptococcus pneumoniae
B) Mycobacterium tuberculosis
C) Klebsiella pneumoniae
D) Influenza virus
E) Rhodococcus equi

Question 3 - Single Best Answer

Which organism causes "rust" colored sputum?   Bugs Database

A) Streptococcus pneumoniae
B) Mycobacterium tuberculosis
C) Klebsiella pneumoniae
D) Influenza virus
E) Rhodococcus equi

Question 4 - Single Best Answer

Which organism causes "currant jelly" sputum?   Bugs Database

A) Streptococcus pneumoniae
B) Mycobacterium tuberculosis
C) Klebsiella pneumoniae
D) Influenza virus
E) Rhodococcus equi

Question 5 - Single Best Answer

What test could you do that would immediately indicate, if positive, that he had TB?   Bugs Database

A) Gram stain of throat swab
B) Gram stain of sputum
C) acid-fast stain of sputum
D) Australia antigen
E) Koplik spots

Question 6 - Single Best Answer

What other tests would you order?   Bugs Database

A) Chest x-ray
B) PPD
C) CBC
D) all of the above

A few acid fast rod-shaped bacteria were seen in his sputum sample. You must await the results of the other tests.

Question 7 - Single Best Answer

What were the acid-fast rods that were seen?   Bugs Database

A) Mycobacterium kansasii
B) Mycobacterium avium-intracellulare complex
C) Mycobacterium leprae
D) Mycobacterium tuberculosis
E) strictly speaking, it is impossible to tell

The next day you received the following test results:

Question 8 - Single Best Answer

Which of the test results are normal?   Bugs Database

A) Chest x-ray
B) haemoglobin
C) WBC
D) erythrocyte sedimentation rate
E) none of the above

Question 9 - Single Best Answer

What result would you expect, based on the finding of acid-fast bacteria, from the PPD test, and when?   Bugs Database

A) redness and swelling (}10mm) at the site of injection after 12 hours
B) redness and swelling (}10mm) at the site of injection after 24 hours
C) redness and swelling (}10mm) at the site of injection after 3 days
D) no reaction at the site of injection

Question 10 - Single Best Answer

If this (redness and swelling at the site of injection after three days) was the result in an individual not demonstrating any acid-fact bacteria (AFB) in a good sputum sample, what would it mean?   Bugs Database

A) the individual definitely does not have active disease, it is an immunological cross-reaction
B) the individual has active TB now, but has not had it in the past
C) he has received BCG
D) the individual has been infected but has no active disease
E) either C or D is correct

Question 11 - Single Best Answer

What is the pathogenesis of the lesion seen on the x-ray?   Bugs Database

A) a granuloma with central (caseous) necrosis
B) an inflammatory response with edema fluid
C) nitrous oxide killing of the bacteria
D) one lobe completely filled with fluid
E) a tumor

The PPD test, read on the third day, shows less than 5mm of induration.

Question 12 - Single Best Answer

Does this (less than 5mm redness and swelling at the site of injection of the PPD) mean that Mr. Dough does not have infection by Mycobacterium tuberculosis?   Bugs Database

A) yes
B) no

Question 13 - Single Best Answer

What other tests should have been or should now be done?   Bugs Database

A) hypersensitivity to Candida albicans
B) HIV antibody
C) Culture of M. tuberculosis
D) hypersensitivity to penicillin
E) A, B, C

Question 14 - Single Best Answer

When would you start antimicrobial therapy for this patient?   Bugs Database

A) After a culture has confirmed that he has TB
B) After a repeat PPD test that is positive
C) After acid-fast bacteria were seen in his sputum
D) After the results of his HIV test, because this will effect the type of therapy he gets

Question 15 - Single Best Answer

What would the recommended therapy be?   Bugs Database

A) penicillin and streptomycin
B) isoniazid alone
C) isoniazid plus ethambutol
D) isoniazid plus rifampin
E) isoniazid plus rifampin plus pyrazinamide

Question 16 - Single Best Answer

How long is a course of TB therapy?   Bugs Database

A) until his PPD test is negative
B) one month
C) 6-18 months
D) five years
E) forever

Question 17 - Single Best Answer

Which of the following is a big problem in treating TB?   Bugs Database

A) teaching patients to administer the drugs intravenously
B) side effects of the drugs which include mental instability
C) patient compliance

The culture was positive for M. tuberculosis after 28 days. He had a very weak reaction to the Candida antigen, and he was HIV positive.

Question 18 - Single Best Answer

How is M. tuberculosis grown?   Bugs Database

A) the footpad of the armadillo
B) anaerobically on nutrient broth agar
C) in 5% carbon dioxide at room temperature
D) in 5% carbon dioxide at 37 degrees on Lowenstein-Jensen medium
E) In cultures of human macrophages

Question 19 - Single Best Answer

What most likely was the immediate source of Mr. Dough's (active) TB infection?   Bugs Database

A) a sexual partner
B) contaminated food
C) the air in the homeless shelter
D) reactivation of a previous infection

Question 20 - Single Best Answer

What are some things that might have caused the reactivation of the TB?   Bugs Database

A) homelessness
B) alcoholism
C) HIV
D) malnutrition
E) all of the above

Question 21 - Single Best Answer

When Mr. Dough was originally infected with TB, what was the most likely route of the infection?   Bugs Database

A) respiratory
B) fecal-oral
C) sexual
D) insect vector
E) ingestion

Question 22 - Single Best Answer

When Mr. Dough was first infected with TB, what would his symptoms have been?   Bugs Database

A) essentially the same as they are now
B) a cough, but with no hemoptysis
C) a high fever, but no cough
D) he probably would have had no symptoms at all

Question 23 - Single Best Answer

If Mr. Dough had not been HIV positive, what is the most likely thing that would have been seen in his chest x-ray?   Bugs Database

A) his chest would have been normal
B) interstitial infiltrates
C) consolidation
D) a cavitary lesion

Question 24 - Single Best Answer

In what populations is it most likely that TB will be symptomatic on first exposure?   Bugs Database

A) pregnant women and babies
B) babies and AIDS pts
C) alcoholics and homosexuals
D) asthmatics and diabetics
E) people who have not been vaccinated with BCG

Question 25 - Single Best Answer

Which of the following are virulence factors/mechanisms for M. tuberculosis?   Bugs Database

A) cytotoxin
B) superantigen toxin
C) antigenic variation
D) spores
E) intracellular growth

Question 26 - Single Best Answer

Disease manifestations in TB are largely the result of which of the following?   Bugs Database

A) cytotoxicity
B) immunosuppression
C) cellular immune response
D) antigenic cross reactivity

Question 27 - Single Best Answer

Problem(s) in combatting TB during the last five years of the 20th century and into the 21st century will likely be?   Bugs Database

A) antibiotic resistance
B) increased number of AIDS patients
C) increased numbers of people living in poverty and crowded conditions
D) lack of a good vaccine
E) all of the above