We report a case of disseminated tuberculosis with cardiac tamponade in a 26-year-old man from northern Portugal. He was imprisoned for one year before the diagnosis and had no known immunosuppressing conditions. A high level of suspicion with a detailed review of risk factors and exposure history (e.g., in this case, imprisonment is a risk factor for tuberculosis) is necessary when pursuing a diagnosis of extrapulmonary tuberculosis and treatment should be started as soon as possible when life-threatening manifestations occur. We used a 12-month course of antituberculosis agents associated with steroids, in our case. The patient had a good clinical response and no signs of disease at the end of the treatment.