The number of active pulmonary tuberculosis cases has increased in Louisville Metro recently. Symptoms of pulmonary tuberculosis include a chronic cough lasting more than two weeks, fever, night sweats and unintended weight loss.
In the United States, the majority of tuberculosis cases occur in individuals who have emigrated from countries with high rates of the disease, including India, sub-Saharan Africa and the islands of Southeast Asia/Micronesia. About half of these cases occur in individuals who have lived in the U.S. for fewer than five years, and most are the result of a reactivation of a latent Mycobacterium tuberculosis infection. Screening and treatment for latent infection is important for preventing active tuberculosis cases.
Risk factors in addition to this geographic link include impaired immunity, such as from HIV/AIDS; regular treatment with glucocorticoids or tumor necrosis factor (TNF) inhibitors; diabetes; organ transplant; nutritional deficiency; substance abuse; and chronic systemic illness.
Those who are older, male, minority, of lower socioeconomic status or living in congregate settings such as nursing homes and correctional facilities also have an increased risk of tuberculosis.
Screening tests include the purified protein derivative (PPD) skin test and interferon gamma release assay (IGRA) blood test. These tests do not determine active vs. latent disease. Active pulmonary tuberculosis is diagnosed by culturing the bacteria in a respiratory sample. Patients with a positive screening test and a chest X-ray or computed tomography scan showing upper lobe infiltrates, especially posterior or cavitating, should be suspected of having active tuberculosis while awaiting the culture results.
For more information about tuberculosis screenings, contact Paul S. Schulz, M.D., at email@example.com, medical director, Infection Prevention, Employee Health and Antimicrobial Stewardship.