Until the mid-1980s, the number of tuberculosis (TB) cases in the United States had been decreasing. At that point, the decline in the number of TB cases in the United States ended; some areas even began to see increases (CDC, 1989a). What does this mean for long-term care facilities (LTCF)? It means that the likelihood of a patient having tuberculosis is increasing. The reason for the resident being in the LTCF usually is not related to tuberculosis. For this reason, adequate screening for tuberculosis on admission for residents - and on hire and then periodically for staff - and increased awareness of symptoms of tuberculosis has become increasingly important.
To handle patients with TB, the epidemiology, transmission, pathogenesis, infectiousness, and treatment of tuberculosis must be understood. This article details these topics, as well as current recommendations for the prevention, control, and surveillance of tuberculosis.
Tuberculosis crosses all levels of society, but it is not evenly distributed. Each region of the country may have a slightly different profile of their local tuberculosis patient. Nationally, however, the following groups have a higher incidence of TB:
* Hispanice, Blacks, Asian and Pacific Islanders, and Native Americans and Alaskans;
* Residents of correctional institutions, mental institutions, nursing homes/facilities, and other long-term care facilities;
* Alcohol and injecting drug users;
* Persons with medical risk factors that increase the risk of disease if the person is infected (eg, on chemotherapy, or infected with HIV or a disease that decreasesimmunocompetency),and
* Foreign-born persons from areas with a high prevalence of tuberculosis (CDC, 199Oe).
TRANSMISSION: HOW TUBERCULOSIS SPREADS
Tuberculosis is generally spread via airborne routes. The tuberculosis organisms are carried in particles suspended in the air and are referred to as "droplet nuclei." Droplet nuclei are produced when a person coughs, sneezes, laughs, speaks, or sings. Large particles that are produced fall out of air circulation and do not cause infection. It is the small particles (droplet nuclei) - 1 to 5 microns in size - that stay suspended in the air that can cause infection. These droplet nuclei can become distributed throughout a room or building by normal air currents. A susceptible person who inhales the droplet nuclei containing tuberculosis organisms may become infected.
Certain procedures that cause the aerosolization of infected particles have been associated with nosocomial transmission. Examples of such procedures are: open abscess irrigation, sawing (during surgery or autopsy), bronchoscopy, endotracheal suctioning, and sputum induction, or aerosol treatments that induce coughing (CDC, 1990a).
Additional routes of transmission are rare but possible. Transmission can occur accidentally by direct inoculation via puncture of the skin with a contaminated object. Recently, there was a report of a needlestick injury that resulted in an infection mat progressed to nonpulmonary disease (CDC, 1991a). An OR technician (in July 1990) sustained a needlestick injury from a biopsy needle used to obtain a specimen from a tubercular lesion. It is important to remember that nonairborne routes of transmission are rare. Every case, and incidents surrounding each case, must be evaluated individually - on a case by case basis (CDC, 1983).
PATHOGENESIS: HOW TUBERCULOSIS DEVELOPS IN THE BODY
TB organisms that land on the mucociliary blanket of the respiratory tree or on intact mucosa rarely invade tissue to result in infection. If droplet nuclei contaminated with tuberculosis organisms are inhaled and reach the alveoli, infection can occur. A systemic infection occurs when the organisms, which are engulfed by phagocytes, are spread via the lymph and blood streams. This systemic infection is usually silent; that is, the person is not ill or symptomatic. It takes the body 2 to 10 weeks to mount an immune response to limit further spread of the tuberculosis organisms and to control the infection (American Thoracic Society, 1990). Most people (90%) who are infected with tuberculosis never progress from infection to active disease (American Thoracic Society, 1981). However, 10% of persons infected with tuberculosis will progress to active disease sometime later in life. The risk of progressing to active disease is much greater for those individuals who are also infected with HIV (CDC, 1989b).
There are two stages in the tuberculosis process. The first stage is tuberculosis infection and the second stage is tuberculosis disease. Table 1 compares these two stages. The similarities are that in both stages the person has the tuberculosis organisms in their body, is considered infected, and usually has a positive tuberculin skin test. The differences are that a person who is infected only, usually has a normal chest Xray; has negative sputum smears and/or cultures for tuberculosis; has no symptoms; is not infectious; and is not considered a "case" of tuberculosis, but infected (a tuberculin reactor) instead. A person who has active pulmonary tuberculosis disease usually has an abnormal chest Xray; has positive sputum or bronchoscopy specimens for AFB smear and/ or culture; has pulmonary symptoms of cough, sputum production, and occasional hemoptysis or chest pain; has generalized symptoms of fever, night sweats, and weight loss; is frequently considered infectious before starting to respond to treatment; and is considered a case of tuberculosis disease.
INFECTIOUSNESS: WHO IS INFECTIOUS AND HOW INFECTIOUS ARETHEY?
Questions regarding infectiousness do not have simple answers for persons with active disease. Persons who are infected (ie, having a positive tuberculin skin test) but do not have active disease, are not considered infectious (American Thoracic Society, 1990). Persons who do have active disease may or may not be infectious. There are many factors that determine whether a person is infectious or not.
Usual Features Distinguishing lbberculosls Infection from Pulmonary Tuberculosis Disease
Patients with nonpulmonary tuberculosis usually are not considered infectious. There are a few possible exceptions. Nonpulmonary sites of disease may be considered infectious in special circumstances (CDC, 1990a):
* Disease sites in the respiratory tract or oral cavity. For example, laryngeal tuberculosis is included in the pulmonary section because it is considered a very infectious form of tuberculosis; and
* Tuberculosis disease in which an open abscess or lesion has significant drainage that contains high concentrations of tuberculosis organisms.
The use of appropriate barrier precautions should prevent transmission in this setting when handling items soiled with drainage. Additionally, particulate respirator type masks should be worn by staff who perform procedures that cause aerosolization of TB infected particles.
There are many factors that influence infectiousness of pulmonary and laryngeal tuberculosis. These facton can be grouped into three basic categories: clinical features of the case; environment; and contact's exposure information.
Table 2 shows the variables of these factors. Most cases do not fall into the same range in the continuum of less infectious to most likely infectious for all the categories. Each case must be looked at individually and all factors assessed to evaluate how infectious they may have been and the likelihood of transmission for each setting. This information helps to determine the extent of contact (exposure) investigation that is pursued after diagnosis.
TREATMENT CF TUBERCULOSIS: INFECTION AND DISEASE
The recommendations for treatment of infection and disease are usually simple and straightforward. The guidelines discussed below are for simple situations. For more informalion refer to the resource cited.
Treatment for TB infection is usually referred to as preventive therapy or chemoprophylaxis. The recommendation is for isoniazid (INN) to be given for 6 to 12 months. The usual adult dose is 300 mg daily. All persons with a positive Mantoux test should be evaluated for prevenlive therapy (American Thoracic SocietY, 1986).
There are two main treatment regimens recommended in conjunction with the following basic guidelines:
* Two or more antituberculosis drugs, to which the organism is susceptible, are given to treat active disease (note that only one drug, INN, is used for infection);
* In general, regimens adequate to treat pulmonary TB in adults are adequate to treat children and nonpulmonary TB; and
* Be aware of drug-resistance trends in your area and when initiating treatment, and include additional TB drugs to the treatment regimen selected to cover for drug resistance.
Both the 6-month and the 9month regimens have 2 phases: the initial and the continuation. The 6month regimen includes INH, rifampin (RTF), pyrazinamide (PZA), and ethambutol or streptomycin (to cover for drug resistance) for at least 2 months, followed by another 4 months (or 7 months if the patient is infected with HIV) of just INH and RIF. Ethambutol hydrochloride or streptomycin sulfate should be continued until drug susceptibility results are known. If drug resistance is found, if it takes longer than 3 months for the patient to convert their sputum to culture negative, or patient noncompliance develops, the regimen needs to be re-evaluated and lengthened or changed appropriately. The 9-month regimen is the same as the 6-month, except PZA is not included among the drugs used - so the continuation phase is lengthened from 4 months to 7 months.
There have been reports of outbreaks of multidrug-resistant TB in Texas, California, Pennsylvania, Michigan, Florida, and New York (CDC, 1990b; CDC, 1990c; CDC, 1991b; CDC, 1991c). The outbreaks in Florida and New York identified nosocomial transmission not only to HIVinfected patients, but also to health care workers. There were many factors that contributed to the outbreaks, including delays in recognition of active TB disease, inadequate infection control, and delays in recognition of drug resistance. Patients infected with HTV and TB may not present for care with symptoms typically associated with pulmonary TB. This results in delays in TB diagnosis. TB should be considered in any patient who has a persistent cough or other general symptoms of weight loss, fever, anorexia, and night sweats (CEXZ, 1990a). Failure to suspect and cover for drug resistance (pending sensitivity results) can result in additional problems, such as further drug resistance for the patient and increased transmission of the resistant organism due to prolonged periods of infectiousness. Management of infected contacts has many problems because INH is usually one of the drugs to which the organism is resistant.
Factors Influencing Infectiousness of Pulmonary Tuberculosis
For patients who have drug-resistant TB, who are noncompliant with treatment, or who develop intolerance to the drugs, consult with your local public health TB control program for assistance. There is also a reference booklet available through the American Lung Association: Treatment of Tuberculosis and Tuberculosis Infection in Adults and Children 1986 - Control of Tuberculosis 1983. This booklet is a joint statement of the Centers for Disease Control and the American Thoracic Society.
MANAGEMENT OF TUBERCULOSIS IN LONG-TERM CARE FACILITIES
The Centers for Disease Control (CLXZ) has published guidelines for LTCFs entitled "Prevention and Control of Tuberculosis in Facilities Providing Long-Term Care to the Elderly." These guidelines are reprints from the Morbidity and Mortality Weekly Report (CDC, 199Od).
The CDC has broken down the prevention and control activities into four categories: surveillance, containment, assessment, and education.
Routine Screening for TB. Every LTCF should have a policy and procedure for screening all residents and staff for tuberculosis infection. Residents should be screened on admission and when an exposure occurs. Staff should be screened on hire and periodically thereafter (check with your local tuberculosis control program for recommendations in your area). The Mantoux (intradermal) test should be used to identify infected persons. The multiple puncture devices are not recommended. Because false-negative skin test reactions can occur, staff or residents who have symptoms of active tuberculosis should have a complete work-up to rule out active TB - regardless of the skin test reaction size.
Case Finding/Reporting. The local or state health department should be notified when TB is suspected or confirmed among residents or staff, as required by state and local laws. The TB program that receives the report should be able to assist with recommendations regarding appropriate follow-up.
Isolation. To prevent the spread of infection, persons with suspected or confirmed infectious tuberculosis should be placed under appropriate isolation until they have become noninfectious. If the following three conditions are met, the suspect case may remain in his or her usual environment (CDC, 1990d):
1. Treatment with adequate chemotherapy is initiated promptly.
2. Recent and current contacts are evaluated and placed on appropriate therapy.
3. New contacts can be prevented until the patient has become noninfectious.
Treatment. Treatment recommendations published by the American Thoracic Society and the CDC should be followed. Staff should not only dispense, but also observe that the TB medication is ingested by the patient.
Contact Investigation/Contact Follow-up (CFU). An exposure usually occurs when a resident or staff member develops active disease. All too often the disease is not diagnosed until after the person has become infectious, requiring CFU to be initiated. When an exposure occurs, consult the CDC guidelines and your local health department TB control program for consultation regarding which contacts should be examined.
Preventive Therapy. Recommendations for administration of preventive therapy should be followed (CDC, 199Oe). Persons who refuse or who are unable to complete a recommended course of preventive therapy should be reminded of the symptoms of active TB and be advised to seek medical attention promptly should those symptoms develop.
Each facility should keep records of its tuberculosis surveillance data, compliance with preventive therapy, and results of CFU activities. The guidelines published by CDC have a sample record-keeping system in tile appendix (CDC, 199Od).
Education is an integral part of the whole program. The staff needs to be knowledgeable in order to be alert to the signs and symptoms of tuberculosis. They also need knowledge about TB transmission and pathogenesis to understand the importance of following appropriate infectioncontrol procedures, and to cooperate with surveillance activities. Residents and patients need to understand current TB treatment recommendations and how successful they are today if patients are compliant. As health care providers, we need to remember that all of us have our own knowledge base about TB and that those beliefs influence our behavior. The education of both staff and patients should begin with an assessment of their knowledge of TB so that old, erroneous beliefs can be corrected and current knowledge imparted. Only then will we be able to improve understanding and cooperation, and ultimately ensure success in our TB control efforts.
- American Thoracic Society, Centers for Disease Control. Diagnostic standards and classification of tuberculosis. Am Rev Respir Dis 1990; 142:725-735.
- American Thoracic Society, Centers for Disease Control. Diagnostic standards and classification of tuberculosis and other mycobacterial diseases. Am Rev Respir Dis 1981; 123:343-355.
- American Thoracic Society, Centers for Disease Control. Treatment of tuberculosis and tuberculosis infection in adults and children. Am Rev Respir Dis 1986; 134:355-363.
- Centers for Disease Control. TB Notes: Case Report - Tuberculosis lymphadenitis from needle stick. Spring 1991a, pp. 11-12.
- Centers for Disease Control. Guidelines for preventing the transmission of tuberculosis in health-care settings, with special focus on HIV-related issues. MMWR 1990a; 39(no.RR-17):1-26.
- Centers for Disease Control. Guidelines for prevention of TB transmission in hospitals (DHHS Publication No. CDC 83-0015). Atlanta: US Department of Health and Human Services, Public Health Service, 1983 (rev.).
- Centers for Disease Control. Nosocomial transmission of multidrug-resistant tuberculosis among HIV-infected persons - Florida and New York, 1988-1991. MMWR 1991b; 40:585-591.
- Centers for Disease Control. Nosocomial transmission of multidrug-resistant tuberculosis to health care workers and HIVinfected patients in an urban hospital - Rorida. MMWR 1990b; 39:718-722.
- Centers for Disease Control. Outbreak of multidrug-resistant tuberculosis - Texas, California, and Pennsylvania. MMWR 1990c; 39:369-372.
- Centers for Disease Control. Prevention and control of tuberculosis in facilities providing long-term care to the elderly. MMWR 199Od; 39(No.RR-10):7-20.
- Centers for Disease Control. Screening for tuberculosis and tuberculosis infection in high risk populations, and the use of preventive therapy for tuberculosis infection in the United States: Recommendations of the Advisory Committee for Elimination of Tuberculosis. MMWR 1990e; 39(no.RR8):7-8.
- Centers for Disease Control. A strategic plan for the elimination of tuberculosis in the United States. MMWR 1989a; 38(suppl 3):13.
- Centers for Disease Control. Transmission of multidrug-resistant tuberculosis for an HIVpositive client in a residential substance abuse treatment facility - Michigan. MMWR 1991c; 40:129-131.
- Centers for Disease Control. Tuberculosis and human immunodeficiency virus infection: Recommendations of the Advisory Committee for the Elimination of Tuberculosis (ACET). MMWR 1989b; 38:236-238,243250.
Usual Features Distinguishing lbberculosls Infection from Pulmonary Tuberculosis Disease
Factors Influencing Infectiousness of Pulmonary Tuberculosis