Tuberculosis: new threats from an old disease.

TB has made a "comeback," and residents and staff need added protection

Tuberculosis - the name conjures up images of frail individuals coughing into blood-speckled handkerchiefs in remote sanatoriums. Along with this comes the impression that TB is an "old" disease, one from a past generation. Many people believe that TB no longer poses a threat to our health.

Unfortunately, TB has re-emerged with a vengeance, and the residents of nursing homes - and the individuals who work there - are among those at greatest risk.

Consider these alarming facts:

* An estimated 30 to 60% of adults in developing countries have TB infections.

* TB is the leading cause of death worldwide for people over five years of age.

* The World Health Organization declared a global TB emergency only four years ago.

In addition to all this, drug-resistant strains of M tuberculosis have developed. The development of these strains complicates patient treatment and attempts to control the spread of TB. Because individuals with drug-resistant forms of TB remain infectious for a longer period of time, they are more likely to spread the disease to others.

After TB reporting began in 1953, the number of cases in the U.S. dropped approximately 5% each year - until 1984, when the trend began to reverse. Between 1985 and 1993, TB incidence increased 11%. The Centers for Disease Control (CDC) attributed this to:

* an association of TB with the HIV epidemic

* immigration from countries where TB is common

* inadequate funding for TB control and other public health efforts

* transmission of TB in congregate settings - nursing homes, hospitals, correctional facilities and homeless shelters 

The elderly are among those most at risk for TB, since many lived during a time when TB was even more common. For example, based on 1994 data, the rate of new cases of TB disease for all age groups was 9.4 cases per 100,000 people, but for people 65+ years of age it was 16.7 cases per 100,000 people - higher than for any other age group.

Elderly people who live in nursing homes have an even higher risk for acquiring TB. A recent CDC survey reported that the incidence of TB in nursing home residents was 39.2 cases per 100,000 population.

Nursing home employees are also at a greater risk for developing TB. In the CDC study, the observed rate among nursing home employees was three times higher than the rate expected for employed adults of a similar age, race and sex. Investigators also have reported outbreaks of TB in nursing homes where transmission was documented between residents and staff.

The CDC identified the following factors that contribute to outbreaks of TB in healthcare facilities and nursing homes:

* delayed diagnosis of TB

* delayed recognition of drug-resistant strains

* delayed initiation of effective therapy

* inadequate isolation procedures

* inadequate ventilation in TB isolation rooms

* lapses in TB isolation practices

* inadequate precautions for cough inducing procedures

* lack of respiratory protection

The CDC, Occupational Safety & Health Administration (OSHA), and most states have developed recommendations and regulations aimed at controlling the spread of TB. The CDC published Guidelines for Preventing the Transmission of Mycobacterium Tuberculosis in Healthcare Facilities in 1994. The guidelines emphasize the importance of:

* a hierarchy of controls to reduce the risk of transmitting TB, including: administrative measures, engineering controls and personal respiratory protection (each of which will be discussed momentarily)

* use of risk assessment to develop a written TB control plan

* early identification and management of people who have TB

* TB screening programs for healthcare workers

* training and education of healthcare workers

* evaluation of TB infection control programs

In early 1996, OSHA issued its Directive on Enforcement Procedures, Scheduling for Occupational Exposure to Tuberculosis. In the directive, OSHA states that the 1994 CDC guidelines represent an industry recognition of the hazards of TB, as well as appropriate standards of practice to be followed by employers in carrying out their responsibilities under the OSHA Act. OSHA is also expected to issue a proposed health rule later this year that will address exposure to TB in the workplace.

Two recent studies indicate, however, that many healthcare facilities are not compliant with OSHA regulations. Other studies show that many healthcare workers do not have an adequate understanding of TB and its transmission. Both studies can be found in Infection Control and Hospital Epidemiology 1996, Issue No. 17.

One group of researchers investigated long-term care facilities for the elderly and other healthcare institutions, as well as correctional facilities, homeless shelters and drug treatment centers between 1992 and 1994. In terms of administrative controls, compliance was reported in about 80% of the facilities for the identification and isolation of TB patients and skin testing of workers. Lower rates of compliance were reported in other areas, including negative pressure in TB isolation rooms. The lowest figure of compliance was attached to respiratory protection programs, with only 56% of hospitals having a program, and only 27% using approved respirators.

Another study tested healthcare workers' knowledge of the transmission of TB and relevant infection control measures. Less than half of the workers had received any TB education in the past two years, and many were found to be unsure of ways in which TB was transmitted and having inadequate information on the use of infection control measures.

To evaluate a facility's potential risk for TB transmission, a risk assessment should be conducted for an entire facility, as well as areas or occupational groups within the facility. A baseline risk assessment should be conducted initially and reviewed periodically, depending on the classification. The classification of risk is based on: 1) the profile of TB in the community, 2) the number of infectious TB patients admitted to the facility area, and 3) analysis of PPD conversion data for the facility's workers.

According to CDC guidelines, if there are no TB cases in the facility or in the community, then there is essentially no risk of exposure to TB. If cases of TB exist in the community and there is no evidence of transmission in the facility or areas within the facility, then the risk of exposure increases according to the number of cases seen at the facility. If there is evidence of transmission within the facility or areas of the facility, a higher risk level exists.

Actual control measures used by a facility should be determined by the level of risk for transmitting TB at the facility. While a facility with a lower risk does not require the same control measures as one with a higher risk, there are certain measures that all facilities should use - regardless of their extent of risk.

As indicated earlier, TB control program involves three types of controls:

* Administrative measures

* Engineering controls

* Respiratory protection

Administrative Measures. Administrative controls are the primary strategy for infection control. These measures include the prompt detection of suspected cases, isolation of infectious patients and appropriate treatment.

All nursing homes should follow guidelines for the prompt detection of TB cases, including:

1) identification of a specific person to be responsible for designing, implementing, evaluating, and maintaining the TB infection control plan

2) written policies and protocols to ensure the identification, isolation, and treatment of infected people

3) effective work practices (e.g., correctly wearing respirators and keeping doors to isolation areas closed)

4) education, training, and counseling about TB. All healthcare workers should be educated about the basic concepts of TB transmission and pathogenesis, infection control practices, the signs and symptoms of TB and the importance of participating in the screening program. Patients should also receive education about TB transmission, reasons for isolation and the importance of staying in their rooms.

5) coordination of activities with the local public health department to report all confirmed or suspected cases of TB, to ensure that contact investigations are carried out and to develop an appropriate discharge plan.

Engineering Controls. Engineering controls can reduce the concentration of TB in the air and prevent its spread in a facility. Control measures include the use of adequate ventilation systems, which may be supplemented in high-risk areas with high-efficiency particulate air (HEPA) filtration, and ultraviolet germicidal irradiation (UVGI).

In TB isolation rooms, ventilation systems are necessary to exhaust the air regularly. The room should have at least six air changes per hour and should be maintained at negative pressure so that air flows from the halls into the room, preventing contaminated air from escaping. Contaminated air can be directly exhausted to the outside.

Alternatively, air can be passed through a HEPA filter before returning to general circulation. HEPA filters can be installed in ducts to filter air for recirculation into the same room or recirculation into other areas of the facility.

UVGI lamps may be used as an adjunct to ventilation to kill bacteria in the air.

Personal Respiratory Protection. Respiratory protection is required for all staff and visitors who enter a room where patients with known or suspected infectious TB are isolated. The minimal protection required is a NIOSH-approved HEPA particulate air respirator.

A respiratory protection program is essential to teach workers how and when to use personal respirators. All facilities that use respiratory protection devices are required to develop, implement and maintain a respiratory protection program.

To most effectively implement these administrative measures, engineering controls and respiratory protection programs, healthcare facilities should have a staff member with expertise in these areas or retain the services of an outside firm that specializes in their development.

Conclusion

Nursing home administrators must recognize that TB is once again a "modern" disease, with serious implications for nursing homes. Instituting programs to prevent its transmission and educating staff can greatly reduce the risks of residents or staff contracting the disease. In fact, instituting a TB control program is the only way to ensure the protection of residents, employees and visitors.

Robert D. Short, Jr., PhD, PharmD, is director of toxicology for Wellington Environmental Inc., St. Louis, MO, a firm specializing in developing programs for healthcare facilities to manage the risks associated with hazards such as TB. For further information, [phone].