Atlanta lawyer Andrew Speaker sparked a media frenzy and public outrage, when—despite having been told he had active and extensively drug-resistant (XDR) tuberculosis (TB)—he flew to Europe for his 2007 wedding and honeymoon and put his fellow air travelers at risk.
When a federal order—the first of its kind in more than 40 years—quarantined him, further testing revealed he had less-severe multidrug resistant (MDR) TB. The subsequent furor over the case served as a wake-up call to the medical community.
“The Andrew Speaker story reminded hospitalists that Mycobacterium tuberculosis infects up to one-third of the world’s population, about 2 billion people,” says Stephen J. Swanson, MD, a staff physician with Hennepin County Medical Center in Minneapolis.
Dr. Swanson, who works as a pediatric hospitalist and completed a two-year fellowship with the Epidemic Intelligence Service (EIS) for the Centers for Disease Control and Prevention from 2004-2006, would like to see tuberculosis more on hospitalists’ radar screens.
Jay Routson, MD, a teaching hospitalist and clinical assistant professor of medicine in the Idaho State University Department of Family Medicine in Pocatello, says he does not feel entirely up to date on TB testing and MDR TB. “I rely on [infectious disease] and pulmonary specialists if I need the assistance,” he says. The last time he treated a case of suspected TB, the protocol called for four-drug therapy while awaiting sensitivities. He presumes this is unchanged. “I am comfortable with the [purified protein derivative (PPD) test], [polymerase chain reaction (PCR) test], and a bronchoscopic approach, but I’m ready for a review of newer testing modalities.”
Epidemiology
New cases of tuberculosis in the United States have declined since 1993. As of 2006, almost 14,000 cases of active tuberculosis disease were reported—about 4.6 cases per 100,000 population. Foreign-born patients represent a greater proportion of these cases—50% of cases of tuberculosis in all age groups.
“In Minnesota, one-quarter of our foreign-born tuberculosis patients have been in the U.S. for less than a year before they were diagnosed,” Dr. Swanson says. “Most are not arriving with active tuberculosis; they are developing tuberculosis disease and being diagnosed years after their arrival in the U.S.”
In the United States, active tuberculosis often develops in people who acquired latent TB infection in their country of birth and then came to the U.S. Or, they have been exposed to infected people who have recently arrived in the U.S. About 1 million international travelers arrive in the U.S. each day.
But active TB also occurs in U.S.-born individuals (see Fig. 1, above). Risk factors include immunosuppression (e.g., HIV) and being older than 50, reflecting probable exposure to someone with active TB when it was more prevalent in the U.S.
—Stephen J. Swanson, MD, staff physician, Hennepin County Medical Center, Minneapolis.
Misconceptions
Hospitalists should remain aware of the following erroneous beliefs about TB:
Active tuberculosis is primarily being seen with immunocompromised individuals, particularly those with HIV/AIDS. “Not true,” says Dr. Swanson, who is also a pediatric tropical medicine and infectious disease specialist. While the risk of TB disease is greatly increased in the immunocompromised, it occurs most commonly among the immunocompetent.
Tuberculosis is predominantly a pulmonary disease. Also not true. “At least in Minnesota, we know that more than 50% of our reported cases of tuberculosis disease are extrapulmonary,” says Dr. Swanson. “The rate of extrapulmonary tuberculosis is, in fact, much more common in the foreign-born than in the U.S.-born patients.”