First published in 1971, the jointly developed guidelines are intended to advise both public health programs and health care providers in all aspects of the clinical and public health management of tuberculosis in low incidence countries.
Experts believe that about 10 million Americans are infected with TB germs. Yet only about 10 percent of these persons will develop TB disease in their lifetime. The other 90 percent will never get sick from TB or be able to spread the disease to other people. However, throughout the world, TB is a growing problem, especially in Africa where the spread is facilitated by acquired immune deficiency syndrome (AIDS). It is estimated that, worldwide, nearly 1 billion people will become infected, 200 million will become sick, and 70 million will die between now and 2020.
The new guidelines focus on the latest aspects of therapy, including drug administration, the use of fixed-dose combination preparations, the monitoring and management of adverse effects, and drug interaction. Directly observed therapy is advised for patients because of the higher rates of treatment completion.
In the document, there are four recommended regimens for treating patients with tuberculosis caused by drug-susceptible organisms. Each regimen has an initial phase of 2 months followed by the choice of several options for the continuation period of 4 to 7 months.
In these newly revised guidelines, for the first time, regimens recommended for the treatment of TB are based on the strength of the scientific evidence supporting their use. In addition, the responsibility for successful treatment is now clearly assigned to the public health program or private provider, not to the patient.
Furthermore, treatment completion is defined by the number of doses ingested, as well as by the duration of treatment administration.
The guidelines recommend that all patients with tuberculosis have counseling and testing for human immunodeficiency virus (HIV) infection by the time treatment is initiated, if not earlier.
The document notes that the management of HIV-related tuberculosis is complex and requires expertise in the management of both HIV disease and tuberculosis. Management by experts is especially important since HIV patients often take numerous medications, some of which interact with anti-tuberculosis drugs.
During treatment, the guidelines call for microscopic examination of a sputum culture at a minimum of monthly intervals until two consecutive specimens are negative. The guidelines comment that 80 percent of the patients with drug-susceptible organisms who are started on standard four-drug therapy will have a negative culture at 2 months. Patients with a positive culture after two months should undergo careful evaluation to determine the cause. For those not involved in directly observed therapy, the most common cause of a positive culture is nonadherence to treatment.
With regard to children, the guidelines point out that there is a high risk of disseminated TB in infants and children younger than 4 years.
Therefore, treatment should be started as soon as the diagnosis of TB is suspected. In general, the regimens recommended for adults are those of choice for infants, children, and adolescents.
However, one drug called ethambutol is not routinely given to children. Since young persons have a lower bacillary burden, there is less concern that they might develop acquired drug resistance. Directly observed therapy should always be used in treating children.
In pregnant women with suspected TB, because of the risk of the disease being passed to the fetus, treatment should be initiated whenever the probability of disease in the mother is moderate to high. All of the drugs currently recommended do cross the placenta, however, they appear not to have teratogenic effects, according to the guidelines. Streptomycin is the only anti-tuberculosis drug documented to have harmful effects on the human fetus, causing congenital deafness.
Most relapses after treatment occur within the first 6 to 12 months after completion of therapy. The selection of empirical treatment for patients with relapse should be based on the prior treatment scheme and the severity of disease.
Journal
American Journal of Respiratory and Critical Care Medicine