Good morning. TB program, Oregon Health Authority. Can I help you? Hello, this is
Camellia at Benton County Health Department. I just got a report from a
doctor at the community clinic about a patient with tuberculosis. She's 28 years
old she's had signs and symptoms of TB disease her chest x-ray is abnormal but
not cavitary. I advise the clinic on how to collect
sputum the results are back with AFB smear positive two plus and a positive
gene expert the patient is originally from Vietnam and she sought care when
she started coughing up blood and she's had a month of weight loss and three
months of coughing where's the patient no she's on home isolation the doctor
has already started treating her for her pulmonary TB
ok great it sounds like a patient's doctor has the treatments under control
but since she has pulmonary disease and a positive sputum smear she might have
infected her family clinic staff and others right that's why I'm calling it's
been a while since I handled a TV contact investigation and I wanted to
make sure I'm covering all the bases contact investigations for tuberculosis
can be challenging because the infectious period is often long and can
be hard to define clearly other factors influence the urgency and scope of the
investigation TB disease is often but not always infectious in some cases may
be more infectious than others for these and other reasons each TB case
investigation is unique and each situation must be carefully evaluated
before an investigation has started when planning a contact investigation
consider these factors the infectiousness of the case the
infectious period the risk for transmission and individual contact risk
factors such as young age or immuno compromising medical conditions ok let's
start with the case we need to get an idea of how infectious she is and how
long she's been infectious well her sputum smears are positive and
she's been coughing a lot for a long time so she's probably infectious right
yep the TV is in her lungs and her chest x-ray is abnormal we should assume she's
infectious the question now is how long she's been infectious when did she start
coughing she started coughing three months ago mm-hmm got it
okay there are different ways to estimate the infectious period which
makes us a little complicated CDC guidelines start the infectious period
three more months before the onset of symptoms but sometimes it's more
practical to consider the beginning of TB symptoms as the start of the
infectious period your way we're looking at a live infectious period at least
three months and up to six months because the period is so long this could
easily become a really big investigation we want to avoid unnecessary testing but
also need to make sure everyone at high risk is tested we're going really going
to have to focus on understanding the risk of transmission and identify which
contacts at highest risk have you interviewed the case yet not yet okay I
think that's the next priority I'd interview her as soon as you can and
specifically ask questions about who she lives with who visits often and places
like work school or church that she's been to since symptoms started we have a
form on our website you can use for this and hopefully that will help as you
might imagine it can be hard for patients to remember everything it might
be helpful to ask the patient to describe her daily routine
what kind of transportation she uses and what she likes to do in her spare time
etc after you've interviewed the case call me back and we can talk about how
to assess the risk of transmission the infectious period is the time during
which a patient can put others at risk by exposing them to the disease the
infectious period for TB cases is often long the TB pathogen grows slowly and
symptoms can be mistaken for other respiratory conditions resulting in
delayed diagnosis when planning a contact investigation it's important to
assess how infectious the patient is if the patient has pulmonary or plural TB a
contact investigation will be needed usually a contact investigation isn't
needed if the TB diseases elsewhere in the body if after a review of clinical
information you determined that the person is infectious confirmed the date
when symptoms started and use that to calculate the infectious period the next
step is to go through that period and identify when and where the patient
might have exposed others you can then go through that list with the patient to
document names and contact information for people who are likely exposed hi
Heidi its Camilla from Benton County Health
Department just getting back to you about our young lady with tuberculosis
so I have identified 38 contacts there are four adults that live with her three
adults and two children who visit the home regularly six of the staff at the
doctor's office saw her before they realized she might have TB and then they
went ahead and initiated appropriate precautions she takes a community
college class at night and drives to class in a car twice a week with three
friends she works part-time in a nail salon and there are eight other workers
and one supervisor but she's only worked there for a month she went to the
dentist recently so there is the dentist the hygienist and three other office
staff she has a boyfriend and she did mention several other friends she sees
less often this seems like a huge number of people to evaluate yes it does seem
big so we need to think about the places exposure occurred and set some exposure
limits keep in mind that setting exposure limits is not an exact science
let's talk some more about each group of contacts and try to figure out what kind
of exposure they had and whether they have characteristics that put them at
high risk when thinking about exposure limits it's helpful to remember that
even though TB is airborne it's not as infectious as some other pathogens like
measles or pertussis it takes a lot of close contact with an infectious TB
patient to become infected because of this it's helpful to estimate both
cumulative hours of exposure and the type of setting suggested exposure
limits include four or more cumulative hours in a small poorly ventilated space
such as a car or enclosed room eight or more cumulative hours in a
small well-ventilated space such as an apartment 12 or more cumulative hours in
a large space such as a classroom or house or 50 or more cumulative hours in
a large open area such as an auditorium it's also important to consider contact
specific risk factors for example if the contact is a child less than five years
old or is immunocompromised they should be prioritized for testing let me make
sure I have this right all her household members should be tested because they
spent more than 12 hours with her at home the regular visitors also likely
had more than 12 hours of exposure so they should also be tested the three
friends she rides with in the car should be tested because they were there with
her several times in a closed poorly ventilated area but we probably don't
need to test her teacher or other classmates because her class is in a
large auditorium the nail salon is well ventilated she hasn't worked there very
long so it's probably a good idea to test the salon workers but we don't need
to worry about the salon clients each client spent less than an hour with her
and we're several feet away from her and because she's new she doesn't have very
many repeat customers yet the dentist and hygienist might want testing because
they were very close to her but they were wearing surgical masks so that
might decrease their risk the dental office staff didn't spend any
face-to-face time with her so they won't need testing the doctor's office staff
should also be offered testing but they will get that through their own employee
health program the boyfriend probably should be tested but her more casual
friends may not need testing right we don't have a good idea of how much time
she spent with her casual friends so it makes sense to hold off testing them
until we how many close contacts test positive
how many people are in the list for testing then I think that makes 22 we
can manage that okay are a lot of the family members
co-workers and friends foreign-born yes many of them are originally from Vietnam
okay that's important to know because it from an area where TB infection is
common you should keep in mind that they may test positive even if they weren't
infected by this case also it's probably better to give to test them with Kwan of
fear on or teespy instead of a TB skin test if anyone says positive they'll
need a chest x-ray and treatment for latent TB infection for contacts who
test negative you'll need to do a follow-up test eight to ten weeks after
their last exposure to the case TB infection can take several weeks to show
up on tests so it second test is essential to rule out infection okay
all right a couple of other things if there are kids under five or any one
highly immunocompromised they'll need a PA and lateral chest x-ray plus
preventive treatment during the eight to ten week window period regardless of
their test results so for those groups even if the initial Agra or TB skin test
is negative the contact needs of PA and lateral chest x-ray if that's normal
start the contact on L TBI treatment with daily isoniazid or daily rifampin
when it's eight to ten weeks after the last exposure give another eye grub or
TB skin test if the second test is negative we'll need to decide whether to
continue treatment or stop it if it's positive you'll just continue a
treatment does that all make sense yes I understand so kids less than five or
anyone highly immunocompromised need the extra chest x-ray view and should start
treatment for latent tuberculosis regardless of the test result I'll give
you a call at the end of the window period and we can decide whether or not
to continue the treatment you got it also a lot of contacts
positive or contact us TV disease we might need to expand the investigation
feel free to call me if that happens in this module we've reviewed the key
elements of a tuberculosis contact investigation public health activities
will vary from case to case based on the level of infectiousness of the case
patient and the duration and settings of exposure effective tuberculosis contact
investigation depends on good communication between local and state
public health staff the health care provider and the patient these
investigations tend to get complicated but remember you're not alone
support from the state TB program is just a phone call away this is what they
do and they're prepared to support you in this important work