USMLE Q Bank Step 2 CK- 405

A 19-year-old man is referred to the clinic for a positive purified protein derivative (PPD) test for tuberculosis. He moved to the United States from Egypt 2 years ago and has been in a good health. He has no history of fever, cough, weight loss or night sweats. He has no family history or contacts with tuberculosis. His physical examination is normal. His chest x-ray shows no cavitation or hilar adenopathy.

What is the appropriate next step in management for this patient?

A- Repeat the PPD test and x-ray after 6 months

B- Start treatment with isoniazid for 9 months

C- Start treatment with multiple drug- antituberculosis therapy

D- Isolation and full antituberculous therapy for 6 months


This man has a previous exposure to TB, which caused subclinical infection. His history, physical examination and chest x-ray exclude current active TB. He does not need multiple drug treatment at this time but he should take a prophylactic treatment in case there is any dormant infection in his body. The prophylactic treatment for this case is isoniazid for 9 months.

The correct answer is B

11 thoughts on “USMLE Q Bank Step 2 CK- 405”

  1. Thank you for clarifying this point

  2. Thank you Dr Hana

  3. BCG make it subclinical infection which means there are mycobacterium in the bloodstream but they don’t cause clinical picture of TB. Thank you for your question.

  4. Doctor I want to know why insipite of bcg vaccine during childhood ,a person may get infected to tuberculosis??

  5. Thank you so much. I appreciate spending sometime visiting our website. We will be glad to see you coming back.

  6. Its a nice!.

  7. A know a few doctors in USA who send the patient for a Xray. If the xray is negative then they only repeat it every year. How about that?

  8. Personally, I agree with you but unfortunately neither USA Doctors nor USMLE agree with you. I know BCG vaccine is mandatory in some countries like Egypt and it can lead to a positive reaction but also remember that there is still a quiet few cases of active TB even of those who took vaccine. The reason I put this question is that: In order to pass the USMLE, you have to answer it the way they believe is the correct answer in USA even if it is different from what you were taught in schools. Thank you for this great question.

  9. why i give him a prophylactic therapy while he give positive because he was immunized obligatory in egypt previously while he wwas a child

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