A 35-year-old man underwent PPD/TST (tuberculin skin test) testing one week ago. The TST showed 20 mm of erythema and 2 mm induration at the inoculation site. He complains of an occasional dry cough in the mornings but denies fever, chills, weight changes, or night sweats. His medical problems include obesity, type 2 diabetes, and hyperlipidemia. His current medications include aspirin, metformin, and pravastatin. He smokes half a pack of cigarettes daily.
The patient works as an ambulance transport associate at a group home for mentally challenged children, and he occasionally spends time with the same kids supervising various recreational activities. He was born in Haiti and moved to the United States at age 5 with his family. He was tested for HIV with negative results at an employee health screening last year.
His vital signs and physical examination are within normal limits.
The patient's routine blood work during his annual physical last year was within normal limits.
Which of the following is the most appropriate next step in management?

Question

A 35-year-old man underwent PPD/TST (tuberculin skin test) testing one week ago.  The TST showed 20 mm of erythema and 2 mm induration at the inoculation site.  He complains of an occasional dry cough in the mornings but denies fever, chills, weight changes, or night sweats.  His medical problems include obesity, type 2 diabetes, and hyperlipidemia.  His current medications include aspirin, metformin, and pravastatin.  He smokes half a pack of cigarettes daily.
The patient works as an ambulance transport associate at a group home for mentally challenged children, and he occasionally spends time with the same kids supervising various recreational activities.  He was born in Haiti and moved to the United States at age 5 with his family.  He was tested for HIV with negative results at an employee health screening last year.
His vital signs and physical examination are within normal limits.
The patient's routine blood work during his annual physical last year was within normal limits.
Which of the following is the most appropriate next step in management?

Quizplus · Accepted Answer

11ec193a_984b_e1d3_853d_27d43293c691_MD0002_00 This asymptomatic patient presents with a PPD/TST showing only 2 mm induration and 20 mm of erythema. The induration (not erythema) is used to assess reaction, and a > 10 mm increase within a 2-year period is considered a positive test. The significance of overall induration size depends on patient risk factors (summarized in the above table). This patient has no obvious TB risk factors, but he is in a higher risk population (diabetes). However, his TST is < 5 mm induration and is not considered significant. As a result, he needs no further treatment or evaluation for latent TB at this time. Patients with a positive TST should undergo chest x-ray to evaluate for active pulmonary disease (Choice A). Patients with abnormal radiographic findings should be treated with an appropriate regimen and monitoring of cultures. Patients with a normal chest x-ray can be treated for latent TB (e.g., 3 months of INH plus rifapentine or 6-9 months of INH with vitamin B₆) with monitoring of liver function tests (Choice D). ₆ (Choice C) Interferon gamma release assays (IGRAs) are not affected by Bacille Calmette-Guérin (BCG) vaccination status. Quantiferon-TB test (QFT) is one type of IGRA and is preferred in patients with a history of BCG vaccination in whom there is difficulty in interpreting TST results. Educational objective: PPD/TST assesses for latent TB and a positive reaction is based on induration (rather than erythema) and patient risk factors. A positive test requires chest x-ray to rule out active infection. Patients with a negative chest x-ray should be treated with an appropriate regimen in addition to laboratory monitoring. __________ References: Is the tuberculin skin test still suitable to diagnose tuberculosis infection (http://www.ncbi.nlm.nih.gov/pubmed/19622488) Characteristics of a diagnostic method for tuberculosis infection based on whole blood interferon-gamma assay (http://www.ncbi.nlm.nih.gov/pubmed/17154047) Comparing the performance of Quantiferon-TB Gold and Mantoux test in detecting latent tuberculosis infection among Iranian health care workers (http://www.ncbi.nlm.nih.gov/pubmed/22086450)

A 35-Year-Old Man Underwent PPD/TST (Tuberculin Skin Test) Testing One