Tuberculosis
December 30th, 2008 Posted by: admin
Tuberculosis is an ancient disease that remains one of the leading, causes of death. According to one estimate, about half of the world’s population is infected with Mycobacterium tuberculosis, the major causative organism. Of these, 30 million have active tuberculosis, with 10 million new cases and 3 million deaths each year. In the United States, tuberculosis is relatively rare, but there has been an alarming increase in recent years, especially among impoverished people who live in crowded, unsanitary conditions, persons with AIDS, and the elderly.
The incidence of the disease among African Americans in all age groups is twice that of Caucasians. The disease spreads when a person inhales the M. tuberculosis bacilli expelled into the air from the lungs of someone who has an active infection. Typically, when the bacilli enter the lungs, they set off an inflammatory response. Attacking white blood cells, called macrophages, carry the bacilli to lymph nodes, where most are eventually destroyed. Those that escape into the bloodstream travel through the body, prompting the immune system to produce antibodies against them. About 95 percent of patients in the United States with disseminated primary TB heal completely, and most are unaware that they have been exposed. Even so, these individuals still harbor the bacilli, which can be reactivated later. The scenario is quite different for people who are malnourished or weakened by age or disease. In some, the bacilli quietly multiply for months or years before producing symptoms. Others may show signs of TB within a few weeks; weight loss, fatigue, a chronic fever, and night sweats are common. Pulmonary TB is the most frequent type, signaled by a chronic cough that may produce blood streaked sputum. Less often, the infection attacks the kidneys, brain, heart, liver, spine, and other organs and bones.
