A 42-year-old healthcare worker presents for follow-up of a recent tuberculin skin test (TST) which showed 12mm of induration. He has no symptoms of active tuberculosis such as cough, fever, or night sweats. The next most appropriate step in management is to start isoniazid treatment for latent tuberculosis.

1. A 42M, healthcareworker, is seen for followup of a recently placed TST (tuberculin skin test). His previous TST
have been negative. On examination he has 12 mm induration atthe sideof injection.He has no symptoms,
including no cough, fever, chest pain,hemoptysis,pleurisy,or night sweats. He takes no medications.Whatis the
next most appropriatestep in management?
-Obtain an IGRA (interferon gamma releaseassay)
-Start 4 drug treatment for Mycobacterium tuberculosis
-Obtain sputum smear and culture for AFB
-Start isoniazid for latentTB
-Obtain 2 view CXR
-No further treatment
In regard to the PPD, what is the cut off for induration for the followinggroups of patients?
-HIV + patient
-Recent closecontactof a person with activeTB
-Organ transplantpatients
-Persons who injectIVDU
-Residents and employees of high-risk congregate settings
-Persons with no risk factors for TB
How do the sensitivities and the specificities differ between the TST and the IGRA?
Do the TST or IGRA detect activepulmonary TB?
What is an IGRA and what does it measure?
When would an IGRA be preferred to a TST?
When would it be appropriateto obtain both a TST and IGRA, and in what order would you order them?
In regard to treatment of LTBI, what are 4 treatment options? If your patient was HIV+ and on retroviral therapy,
would this changeyour management of latent tuberculosis?
In patients with rheumatoid arthritis setto begin a TNF-alpha inhibitor,whatmeasure of induration on the TST is
considered positive?
How longmust your patient be on treatment for latent tuberculosis prior to beginningthe TNF-alpha inhibitor for
RA?
In regard to activeTB, what are the two most common extrapulmonary complications?
What arethe characteristicsof a tuberculosispleural effusion?
What special testcan you order in the pleural fluid to help identify TB as the cause?