infectious diseases
Tuberculosis (TB)
Prognosis for TB
In immunocompetent patients with drug-susceptible pulmonary tuberculosis, even severe disease with large cavities, appropriate, drug susceptibility test–directed therapy is usually curative if it is instituted promptly and completed. Still, TB causes or contributes to death in about 10% of cases, often in patients who are debilitated for other reasons. Disseminated TB and TB meningitis may be fatal in up to 25% of cases despite optimal treatment. In addition, there is substantial morbidity resulting from residual tissue damage (lungs especially, but any organ) remaining after bacteriological cure. Tissue damage often results from the immune response to infection, most dramatically in the Immune reconstitution inflammatory syndrome (IRIS) (IRIS), but is increasingly recognized in advanced cases of TB, where TB-induced inflammation can lead to, for example, chronic respiratory insufficiency, upper airway stenosis, constrictive pericarditis, and skeletal deformities. Although immune-induced tissue damage is a major problem, the lack of an immune response is an even greater problem. TB progresses more rapidly and more extensively in immunocompromised patients and, if not appropriately and aggressively treated, can be fatal in as little as 2 months from a patient's initial presentation, especially with multidrug-resistant TB (MDR-TB). However, with effective antiretroviral therapy (and appropriate anti-TB treatment), the prognosis for patients with HIV infection, even those with MDR-TB, may approach that of immunocompetent patients. Poorer outcomes have occurred in patients with extensively drug-resistant TB because of less effective treatment, but this is rapidly changing as new regimens address highly drug-resistant TB. 