An adult with newly diagnosed tuberculosis is most likely to have which of the following types of lesions?
This is something of a trick question, but it stresses an impoant fact many medical students do not realize. Primary tuberculosis infection characteristically involves the lung subjacent to the pleura in either the lower pa of the upper lobe or the upper pa of a lower lobe of one lung. The mediastinal nodes are also usually involved , rather than having a single lesion subjacent to the pleura without lymph node involvement. However, the "trick" pa of this question rests on the fact that roughly 80% of newly diagnosed pulmonary tuberculosis cases in adults are actually due to reactivation of an often clinically unsuspected infection acquired years-to-decades previously. The reinfection site usually is in the apex of the lung. You should also be aware that the lungs are not the only site where tuberculosis can occur (it can occur throughout the body), and isolated gastrointestinal involvement is (uncommonly) also seen. Ref: Raviglione M.C., O'Brien R.J. (2012). Chapter 165. Tuberculosis. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.
A single lesion in a lung apex
A single lesion in the gastrointestinal tract
A single lesion subjacent to the pleura
Both a lesion subjacent to the pleura in the lower pa of an upper lobe and active disease in the mediastinal lymph nodes