Vol. 18 •Issue 24 • Page 10
TB in Nursing Homes: A Sleeping Beast
Rates are Down Nationwide, But the Ancient Disease Preys on Elderly
Like that southern California earthquake everyone fears might hit one day, the possibility of an outbreak of tuberculosis among one uniquely fragile population–residents in a nursing home–keeps health officials in a state of quiet anxiety.
“When things are going well, that’s great. But let your guard down, and TB will raise its ugly head,” Ken Castro, MD, director of the Division of TB Elimination at the Centers for Disease Control and Prevention (CDC), told ADVANCE.
And things are going well these days regarding TB. The nation hasn’t seen a TB outbreak in a nursing home or anywhere else in many years. In fact, America’s TB caseload has steadily dropped during the past decade. Last year saw the lowest number of overall cases in the United States at 4.9 per 100,000.
But Castro balanced the good news with a caveat. “These are very tenuous gains,” he said. “It illustrates how TB control requires sustained effort. Right now, there is still a renewed effort and attention maintained over the past 12 years or so from the TB resurgence of the early 1990s.”
Vigilance is especially critical when it comes to the elderly, who persistently have the highest TB rates of any age group. In 2003, the TB case rate for those older than 65 was 7.8 per 100,000, compared to 3.8 per 100,000 in the 15-to-24 age group.
Castro and other officials know a TB outbreak in a nursing home could be just a few missed safeguards away.
“Concentrations of elderly persons, many of whom are infected with tubercle bacilli and some of whom are immuno-suppressed, create high-risk situations for tuberculosis transmission,” warned a CDC document on TB control published in 1990.1
The percentage of TB cases among residents of long-term care facilities has remained stable over the past few years. In 2004, the last year for which statistics are available, residents in long-term care were just 2.4 percent of the nation’s total TB cases.
Efforts like those by officials within the Arkansas Department of Health help explain why.
The 48,114 new residents admitted to nursing homes in Arkansas between 1996 and 2002 were each screened with a tuberculin skin test, allowing Arkansas health department staff to identify and quickly treat test converters.
As a result of its stepped-up surveillance, Arkansas’s TB case rate dropped from 302 per 100,000 new admissions to in-state nursing homes down to just 18 per 100,000 over those six years.
“They were probably ahead of the curve when looking at TB in these settings,” Castro said of Arkansas health officials. “They worked to bring this to public attention and they influenced advisory councils to include nursing homes when discussing TB control methods.”
California, with a much larger population, has had even greater success in quelling TB in its nursing homes. In 2004, California had 2,989 total cases of active TB, with just 60 of them (2 percent) occurring among residents of long-term care facilities.
“All newly admitted residents are given a general overall physical exam including blood, urine and TB skin test,” explained Norma Arceo, public information officer for the California Department of Health Services in Sacramento.
“All nursing home residents must be screened on admission, although the method of screening is up to the facility. And all employees must be screened with a tuberculin skin test within seven days of employment.”
Asked why TB is more prevalent in the 65-and-older set, Castro said: “It probably has to do with people in that age range exposed to TB as children. TB was more common then. You don’t need to go too far back in your or my family tree to find relatives who had TB.”
Latent infection results from exposure to the tubercle bacillus, he added. “If your immune system can control the bacillus, you may never know you have it. But age leads to a deterioration of the immune system. The bacillus can gain the upper hand, usually in the form of respiratory TB.”
Castro is less worried about members of the baby boomer generation, who will occupy nursing homes in typically massive numbers in 20 years or so.
“We think the baby boomer population was less likely to be exposed to the tubercle bacillus as children than their parents and grandparents, unless they are in a risk group like racial/ethnic minorities or have worked in countries where TB is common,” he said. “It’s not aging per say that puts you at risk but the time when you encountered the tubercle bacillus.”
As with younger age groups, most elderly tuberculosis patients have pulmonary disease, according to CDC surveillance data. Because more than half have sputum smears positive for acid-fast bacilli, they are potentially capable of transmitting the infection to other persons.
That reality puts nursing home employees at increased risk as well. According to the CDC, the observed case rate among nursing home employees was three times higher than the rate expected for employed adults of similar age, race and sex.
In past nursing home outbreaks, the source case has usually been a resident, but it may also be a staff member. In such situations, isoniazid preventive therapy effectively reduces the risk of tuberculosis among contacts of newly infected elderly persons, the CDC recommends.
Sporadic outbreaks tend to take place when nursing home residents develop signs and symptoms of TB but a diagnosis is missed initially and treatment is delayed, according to Castro.
“We need to remain vigilant,” he said. “When clinicians who work in that setting see older persons with the signs and symptoms of TB, they must test those patients appropriately, catch disease early on, get reactors the right medications and interrupt the chain of transmission.”
If a nursing home worker misreads the signs of TB, attributes coughing to bronchitis and gives antibiotics, then that patient remains in the company of others and is a threat to transmit TB, he said.
Put residents who test positive in isolation and make sure that the negative pressure systems in your isolation rooms are engineered properly and work, Castro advised further.
“And the last layer of protection is to observe coughing and sneezing etiquette,” he said. “Make sure residents use tissues and cover their mouths when coughing and sneezing so they don’t aerosolize the bacillus.”
A nursing home must also make sure to have in place a surveillance system to monitor latent TB infection among its workers, Castro added. This is often the first indication that TB trouble is lurking.
Since 1990, most states have followed the CDC’s 1990 guidelines issued specifically for residents and employees of nursing homes.1
CDC spokesperson Jennifer Ruth listed these key points of the guidelines:
• Skin tests should be administered to all new residents and employees as soon as their residency or employment begins unless they have documentation of a previous positive reaction. A two-step procedure is advisable for the initial testing of residents and employees in order to establish a reliable baseline.
• Skin-test-negative employees and volunteers having contact (of greater than or equal to 10 hours per week) with elderly residents should periodically have repeat skin tests. The recommended frequency of repeat testing depends on the risk of tuberculosis infection in that facility.
• Each tuberculin-positive resident should be evaluated annually, and a record should be kept that documents the presence or absence of symptoms of tuberculosis (e.g., weight loss, cough, fever). Repeat skin tests should be provided for tuberculin-negative residents and employees after any suspected exposure to a documented case of active tuberculosis.
The full CDC recommendations are available at http://www.cdc.gov/mmwr/preview/mmwrhtml/00001711.htm.
CDC updated its TB recommendations in 1994 and the center is “about to release new recommendations at the end of this year on TB infection control precautions,” Castro added. “These are very broad-based to prevent transmission in all health care settings.”
In fact, a draft of these guidelines has already been put in the federal register for public comment (available at http://www.cdc.gov/nchstp/tb/Federal_Register/New_Guidelines/TBICGuidelines.pdf).
1. Prevention and Control of Tuberculosis in Facilities Providing Long-Term Care to the Elderly Recommendations of the Advisory Committee for Elimination of Tuberculosis. MMWR. (1990: 39 (RR-10); 7-20).
You can reach Michael Gibbons at email@example.com.