A 20-year-old man from Mexico presents to the emergency room in a South Texas hospital with a persistent cough for 3 weeks, low-grade fever, and night sweats. His chest x-ray shows mediastinal and right hilar lymphadenopathy and right upper lobe consolidation concerning for primary tuberculosis (Figure 54-1). Upon review of the radiograph, the emergency room staff admits the patient to a single room with negative pressure. The patient is placed in respiratory isolation, sputum is sent for acid-fast bacillus (AFB) stain and cultures, and the results show acid-fast bacilli consistent with Mycobacterium spp. (Figure 54-2). While culture results are pending, the patient is started on 4 antituberculosis drugs. Fortunately, the sputum culture result shows pan susceptible Mycobacterium tuberculosis, and his treatment continues with directly observed therapy through the local city health department.
Typical presentation of a primary pulmonary tuberculosis infection in a 20-year-old man. A. Frontal chest radiograph shows mediastinal and right hilar lymphadenopathy (black arrows) and right upper lobe consolidation (white arrow). B. Contrast-enhanced CT demonstrates low-density enlarged mediastinal lymph nodes with rim peripheral enhancement consistent with necrotizing lymphadenopathy (arrows). (Courtesy of Carlos Santiago Restrepo, MD.)
The acid-fast bacilli of Mycobacterium tuberculosis seen with acid-fast staining at 100 power with oil immersion microscopy. (Courtesy of Richard P. Usatine, MD.)
Tuberculosis (TB) is a bacterial infection caused by M. tuberculosis, an obligate intracellular pathogen that is aerobic, acid fast, and nonencapsulated. TB primarily involves the lungs, although other organs are involved in one-third of cases. Improvements in diagnostics, drugs, vaccines, and understanding of biomarkers of disease activity are expected to change future management of this devastating worldwide disease.
- More than 8 million cases occur annually around the world, with nearly 2 million TB-related deaths1; 95% of TB deaths occur in low- and middle-income countries.
- A total of 11,182 TB cases (3.6 per 100,000 persons) were reported in the United States in 2010. This represents the lowest incidence rate since recording began in 1953.2 An estimated 2 billion people worldwide have latent TB.3
- The multiple-drug resistant (MDR) TB rate in the United States was 1.2% (88 cases) in 2010; a rate that remains relatively stable in the United States.1 MDR TB rates are highest in India, China, the Russian federation, South Africa, and Bangladesh.3
- Based on the 2010 data, 60% of reported U.S. cases of M. tuberculosis occurred in foreign-born individuals (case rate 11 times higher than U.S.-born individuals).1
- There were 547 reported deaths from TB in the United States in 2009 (a 7% decrease from 2008).1
- Prophylactic treatment of those with latent TB (infection without active ...