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TUBERCULOSIS, HOSPITAL EXPOSURES - USA (WISCONSIN)
A woman who cares for patients at UW [University of Wisconsin]
Hospital and the Veterans Hospital in Madison [Wisconsin] has
tuberculosis [TB], which has prompted officials to test about 30 of
her co-workers for the potentially fatal lung disease and try to
contact up to 150 patients who may have been exposed. The woman,
whose identity and job position hospital officials wouldn't provide,
is thought to have been contagious for only a few days or not at all,
said Dr. Dennis Maki, an infectious disease specialist at UW Hospital.
Though TB can be spread through the air, it generally requires close,
prolonged contact, Maki said. It would take about 6 months for most
people who were exposed to develop active disease, he said. Maki said
it's too early to know if the woman has multidrug-resistant TB [MDR],
which is more of a public health threat. Tests to determine that
could take another few weeks. "The people probably at greatest risk
are the other health-care workers she has worked closely with the
last 2 months," Maki said. Those people are getting skin tests this
week, he said. Any of them who test positive will be given
antibiotics to prevent the development of active disease.
For patients, dozens of whom will be sought out soon by their doctors
for skin tests, "I don't think there's any reason for them to be
concerned," Maki said.
The woman, whose routine annual skin test for TB was negative in
November [2006], became ill about 3 weeks ago, he said. She didn't
have a cough or other respiratory symptoms typical of TB, he said.
Her main complaint was abdominal pain, for which she underwent
surgery last week [20-26 Aug 2007], he said. During the surgery,
abnormal tissue samples raised suspicion of TB, Maki said. After
surgery, he said, the woman was put in an isolation room, with
negative air pressure to contain germs and rules requiring workers to
wear special masks. She was given antibiotics. A few days later, lab
results from the tissue samples were positive for TB, Maki said. The
woman then underwent the definitive test for TB, of her sputum. It
was positive. The woman returned home Tuesday [28 Aug 2007] and is
recovering well, Maki said. She will be on antibiotics for several months.
Maki and other officials said they wouldn't identify her or her
position because of privacy laws. Because the woman didn't have the
typical symptoms of TB, notably a cough that could easily spread the
disease, she probably wasn't contagious, Maki said. "If she was
contagious, it was probably only in the last days before she was
diagnosed," he said.
Skin test results on her co-workers should come back by next week
[3-9 Sep 2007]. If they are negative, it probably means she wasn't
contagious to anyone, though follow-up tests will still be performed,
Maki said. Other co-workers who don't work with her as closely will
be screened for TB during this year's [2007] annual skin tests this
fall, he said. Nearly 5000 people work at both hospitals. Letters
will go out next week to the primary care doctors of up to 150
patients who may have been exposed, Maki said.
Dane County had 9 cases of active TB last year [2006], said Julie
Halvorsen, a nursing supervisor with the Madison-Dane County Health
Department. The county has had 4 cases this year [2007], including
the UW Hospital worker.
[Byline: David Wahlberg]
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[A map of Wisconsin can be found at
<http://www.wistravel.com/map_of_wisconsin/>.
Madison is the capital of the US state of Wisconsin and the county
seat of Dane County. It is also home to the University of Wisconsin-Madison.
Transmission of tuberculosis depends on the infectivity of the
patient, ventilation of the space in which exposure takes place, and
duration of exposure. Usually infectious patients have cavitary
tuberculosis and are coughing or sneezing that generates a large
quantity of aerosols that contain tubercle bacilli. This degree of
infectivity is indicated by a positive smear of sputum stained
specifically for mycobacteria (acid fast or AFB (acid-fast bacillus)
smear). Prolonged, close contact in poorly ventilated spaces enhances
transmission.
Tuberculosis has long been known to be a risk for health care
workers. Indeed, we published an extensive outbreak of latent and
active tuberculosis in an academic medical center in 1965 (N Engl J
Med 1965; 275: 718-21); hospital outbreaks of TB occurred in the
1980's among AIDS patients and healthcare workers, and hospital
outbreaks of multidrug-resistant (MDR) TB occurred in the 1990's.
Hospital employees with patient contact are tuberculin skin tested at
least annually to assess recent acquisition of tuberculosis. If the
hospital employee in the news release above was tested annually for
many years and the tuberculin skin test had been consistently
negative, followed by a positive one year later, then the positive
tuberculin reaction would be the result of an infection acquired
within the prior year. The rapid progression in hospital employee in
the above news release from latent infection acquired less than 6-8
weeks before or at some time after her negative skin test in November
2006 to extra-pulmonary disease suggests some degree of
immunosuppression. We are not told of any co-morbidities in this
hospital worker.
However, if she were 1st employed the prior year and had not been
tuberculin skin tested before, an initial negative tuberculin test
may represent tuberculin hypersensitivity that has waned over the
years after latent tuberculosis that was acquired in childhood. The
initial tuberculin skin test, although negative at the time, can
nevertheless stimulate the waned hypersensitivity to tuberculin. This
boosted hypersensitivity can develop within several days of testing
and persist. A subsequent positive tuberculin test then may be either
the result of a newly acquired infection or the "booster effect". A
booster effect can be assessed in someone who will undergo annual
testing, such as a hospital employee, by repeat testing one week
after an initial negative test; if the 2nd test is positive, the
reaction is due to the booster effect.
The hospital worker in the news release was suspected to have
intra-abdominal tuberculosis on visual exam of the tissues during
abdominal surgery. The exact intra-abdominal site is not specified;
it could be intestine, lymph node, peritoneum, or a visceral organ.
The lab tests, which were said to be "positive" a few days after
surgery, may have been a positive smear for acid-fast bacilli, but
the acid-fast organism could be _Mycobacterium tuberculosis_ or
non-tuberculous mycobacteria. Nucleic acid amplification (NAA) tests
are available for rapid laboratory diagnosis of _M. tuberculosis_ on
respiratory specimens, but I don't believe they have been as yet
FDA-approved for non-respiratory specimens -- although some specialty
labs will do a NAA test on non-respiratory specimens. The news
release says that the patient then had a "definitive" positive test
for TB on her sputum; a positive NAA test on sputum, although rapid,
is only presumptive of TB
(<http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4926a3.htm>); the
definitive test is a culture, but cultures require at least 2 weeks.
We are told that the hospital worker was thought to be "contagious
for only a few days or not at all" because she had no cough, but we
don't know her chest X-ray findings, nor do we know for sure if her
sputum smears were positive for acid-fast bacilli. Certainly if she
had been coughing and producing sputum that was acid-fast bacilli
smear-positive with pulmonary cavities seen on chest X-ray, she would
be considered to be contagious.
We also don't know the status of her family or other household
contacts. If she has children who are skin test tuberculin-positive,
either she or someone else in her household is likely contagious. - Mod.ML]
http://tinyurl.com/34uwer
A woman who cares for patients at UW [University of Wisconsin]
Hospital and the Veterans Hospital in Madison [Wisconsin] has
tuberculosis [TB], which has prompted officials to test about 30 of
her co-workers for the potentially fatal lung disease and try to
contact up to 150 patients who may have been exposed. The woman,
whose identity and job position hospital officials wouldn't provide,
is thought to have been contagious for only a few days or not at all,
said Dr. Dennis Maki, an infectious disease specialist at UW Hospital.
Though TB can be spread through the air, it generally requires close,
prolonged contact, Maki said. It would take about 6 months for most
people who were exposed to develop active disease, he said. Maki said
it's too early to know if the woman has multidrug-resistant TB [MDR],
which is more of a public health threat. Tests to determine that
could take another few weeks. "The people probably at greatest risk
are the other health-care workers she has worked closely with the
last 2 months," Maki said. Those people are getting skin tests this
week, he said. Any of them who test positive will be given
antibiotics to prevent the development of active disease.
For patients, dozens of whom will be sought out soon by their doctors
for skin tests, "I don't think there's any reason for them to be
concerned," Maki said.
The woman, whose routine annual skin test for TB was negative in
November [2006], became ill about 3 weeks ago, he said. She didn't
have a cough or other respiratory symptoms typical of TB, he said.
Her main complaint was abdominal pain, for which she underwent
surgery last week [20-26 Aug 2007], he said. During the surgery,
abnormal tissue samples raised suspicion of TB, Maki said. After
surgery, he said, the woman was put in an isolation room, with
negative air pressure to contain germs and rules requiring workers to
wear special masks. She was given antibiotics. A few days later, lab
results from the tissue samples were positive for TB, Maki said. The
woman then underwent the definitive test for TB, of her sputum. It
was positive. The woman returned home Tuesday [28 Aug 2007] and is
recovering well, Maki said. She will be on antibiotics for several months.
Maki and other officials said they wouldn't identify her or her
position because of privacy laws. Because the woman didn't have the
typical symptoms of TB, notably a cough that could easily spread the
disease, she probably wasn't contagious, Maki said. "If she was
contagious, it was probably only in the last days before she was
diagnosed," he said.
Skin test results on her co-workers should come back by next week
[3-9 Sep 2007]. If they are negative, it probably means she wasn't
contagious to anyone, though follow-up tests will still be performed,
Maki said. Other co-workers who don't work with her as closely will
be screened for TB during this year's [2007] annual skin tests this
fall, he said. Nearly 5000 people work at both hospitals. Letters
will go out next week to the primary care doctors of up to 150
patients who may have been exposed, Maki said.
Dane County had 9 cases of active TB last year [2006], said Julie
Halvorsen, a nursing supervisor with the Madison-Dane County Health
Department. The county has had 4 cases this year [2007], including
the UW Hospital worker.
[Byline: David Wahlberg]
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[A map of Wisconsin can be found at
<http://www.wistravel.com/map_of_wisconsin/>.
Madison is the capital of the US state of Wisconsin and the county
seat of Dane County. It is also home to the University of Wisconsin-Madison.
Transmission of tuberculosis depends on the infectivity of the
patient, ventilation of the space in which exposure takes place, and
duration of exposure. Usually infectious patients have cavitary
tuberculosis and are coughing or sneezing that generates a large
quantity of aerosols that contain tubercle bacilli. This degree of
infectivity is indicated by a positive smear of sputum stained
specifically for mycobacteria (acid fast or AFB (acid-fast bacillus)
smear). Prolonged, close contact in poorly ventilated spaces enhances
transmission.
Tuberculosis has long been known to be a risk for health care
workers. Indeed, we published an extensive outbreak of latent and
active tuberculosis in an academic medical center in 1965 (N Engl J
Med 1965; 275: 718-21); hospital outbreaks of TB occurred in the
1980's among AIDS patients and healthcare workers, and hospital
outbreaks of multidrug-resistant (MDR) TB occurred in the 1990's.
Hospital employees with patient contact are tuberculin skin tested at
least annually to assess recent acquisition of tuberculosis. If the
hospital employee in the news release above was tested annually for
many years and the tuberculin skin test had been consistently
negative, followed by a positive one year later, then the positive
tuberculin reaction would be the result of an infection acquired
within the prior year. The rapid progression in hospital employee in
the above news release from latent infection acquired less than 6-8
weeks before or at some time after her negative skin test in November
2006 to extra-pulmonary disease suggests some degree of
immunosuppression. We are not told of any co-morbidities in this
hospital worker.
However, if she were 1st employed the prior year and had not been
tuberculin skin tested before, an initial negative tuberculin test
may represent tuberculin hypersensitivity that has waned over the
years after latent tuberculosis that was acquired in childhood. The
initial tuberculin skin test, although negative at the time, can
nevertheless stimulate the waned hypersensitivity to tuberculin. This
boosted hypersensitivity can develop within several days of testing
and persist. A subsequent positive tuberculin test then may be either
the result of a newly acquired infection or the "booster effect". A
booster effect can be assessed in someone who will undergo annual
testing, such as a hospital employee, by repeat testing one week
after an initial negative test; if the 2nd test is positive, the
reaction is due to the booster effect.
The hospital worker in the news release was suspected to have
intra-abdominal tuberculosis on visual exam of the tissues during
abdominal surgery. The exact intra-abdominal site is not specified;
it could be intestine, lymph node, peritoneum, or a visceral organ.
The lab tests, which were said to be "positive" a few days after
surgery, may have been a positive smear for acid-fast bacilli, but
the acid-fast organism could be _Mycobacterium tuberculosis_ or
non-tuberculous mycobacteria. Nucleic acid amplification (NAA) tests
are available for rapid laboratory diagnosis of _M. tuberculosis_ on
respiratory specimens, but I don't believe they have been as yet
FDA-approved for non-respiratory specimens -- although some specialty
labs will do a NAA test on non-respiratory specimens. The news
release says that the patient then had a "definitive" positive test
for TB on her sputum; a positive NAA test on sputum, although rapid,
is only presumptive of TB
(<http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4926a3.htm>); the
definitive test is a culture, but cultures require at least 2 weeks.
We are told that the hospital worker was thought to be "contagious
for only a few days or not at all" because she had no cough, but we
don't know her chest X-ray findings, nor do we know for sure if her
sputum smears were positive for acid-fast bacilli. Certainly if she
had been coughing and producing sputum that was acid-fast bacilli
smear-positive with pulmonary cavities seen on chest X-ray, she would
be considered to be contagious.
We also don't know the status of her family or other household
contacts. If she has children who are skin test tuberculin-positive,
either she or someone else in her household is likely contagious. - Mod.ML]
http://tinyurl.com/34uwer
