There is a clear difference between TB infection and TB. Transition from the former to the latter involves host factors and perhaps environmental elements. Currently, more individuals with immunosuppressive situations caused by aging, debilitating diseases, immunosuppressive therapies, and HIV-III infection are predisposed to secondary forms of TB. Different patterns of clinical presentation, at variance with those previously described, could result from these changes in the host. PTBA is a good example. In the present review of 52 patients, we found that patient age is rising, as has been reported in other western countries. We also found that oligoarthritis and involvement of non-weight-bearing joints is becoming more common. From the diagnostic point of view, histological studies and cultures of synovial tissue remain the most reliable tests. Awareness of these factors, recognition of changing patterns, proper use of diagnostic procedures, and early treatment should improve the outcome of patients.