Almost two years ago, a woman died from tuberculous meningitis after several weeks of excruciating headaches. Claudia Lacson was a physician in Atlanta, with access to the best medical care available. Several years prior to her illness, she'd had a positive tuberculin skin test and subsequently completed treatment. According to her husband, Dr. Lacson had wondered whether her headaches indicated tuberculous meningitis. Unfortunately, other, more likely, diagnoses were considered first.
More than four decades earlier, a very famous and wealthy woman died of miliary tuberculosis at a hospital in New York City. Her name was Eleanor Roosevelt. The likely source of Ms. Roosevelt's infection was a reactivation of walled-off Mycobacterium tuberculosis that had remained dormant in her lungs for more than 40 years.
Dr. Lacson became ill when she was pregnant; in Ms. Roosevelt's case, she was being treated with steroids for persistent anemia. Both pregnancy and steroid use are factors known to increase the risk of developing active tuberculosis from latent tuberculosis infection.
What if the women's care providers had remembered to "Think TB"? Would these deaths have been prevented? We'll never know. The delayed diagnosis of tuberculosis can in each case be partially attributed to the fact that nonpulmonary clinical presentations account for 15% of active cases.
In all cases, however, clinicians must do better at diagnosing it. According to the Centers for Disease Control and Prevention (CDC), each year there are almost 15,000 new cases of tuberculosis in the United States and almost 9 million new cases diagnosed worldwide. Yet even when clinicians know that latent tuberculosis infections and risk factors for reactivation are present, they often don't recognize the signs and symptoms of the disease soon enough. Missed opportunities for early intervention lead to poorer outcomes, and others can be exposed when a person with active pulmonary or laryngeal tuberculosis isn't managed with airborne infection isolation precautions. At the same time, providers who know they have latent tuberculosis may bear an extra responsibility to undergo treatment; in December 2005 the New York Times reported that a nurse at a New York City hospital, having developed active tuberculosis after 11 years of latency, exposed more than 1,500 patients and infected four infants.
Nothing is more important than to 'Think TB.'
Successful detection, monitoring, and treatment of latent tuberculosis infections remain crucial to reducing the number of active tuberculosis cases. The tuberculin skin test (TST), which uses a purified protein derivative, has long been the only way to screen for latent tuberculosis infection. A new blood assay for M. tuberculosis (QuantiFERON-TB Gold) is now available and has been approved by the Food and Drug Administration for all situations in which the TST is used. The test eliminates certain interpretive and logistic challenges posed by the TST.
It's crucial to "Think TB" when caring for patients known to have latent tuberculosis or who exhibit symptoms consistent with the active disease. This means prompt evaluation and, where necessary, the use of airborne infection isolation as a precautionary measure until a diagnosis is confirmed. We must also improve diagnostic and treatment skills among health care students. The National Tuberculosis Curriculum Consortium (http://ntcc.ucsd.edu) is funded for this purpose by the National Heart, Lung, and Blood Institute of the National Institutes of Health, and resources are available from organizations such as the CDC and the World Health Organization to increase awareness of tuberculosis. The Bill and Melinda Gates Foundation and others provide millions of dollars each year to address tuberculosis research, diagnosis, and treatment worldwide.
Nothing is more important than for health care professionals to "Think TB." It's good for their patients' health-and for their own.