Self-Study Modules on Tuberculosis
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5: Infectiousness and Infection Control
Answers To Case Studies
5.1. For each of the following situations, decide whether
the patient should be considered infectious or noninfectious, and
5.2. You are checking patients into the TB clinic. An elderly
man comes to the desk and says he was told to come and get checked
because one of his friends has TB. You notice that he looks sick and
is coughing frequently. The waiting room is full of patients, and
you know it will probably be more than an hour before the physician
can see him.
- Mr. Lopez started TB treatment 7 days ago. He still
has a cough. Two weeks ago, he had a sputum smear that was positive;
since then no sputum specimens have been tested.
Mr. Lopez should be considered infectious. He does not meet
the criteria for noninfectiousness because (1) he has been receiving
treatment for only 7 days, not 2 to 3 weeks, (2) his symptoms
haven't improved, and (3) he doesn't have three consecutive
negative sputum smears.
- Ms. Nguyen, a patient with pulmonary TB, has been receiving
TB treatment for 6 weeks, and she no longer has symptoms of TB.
She has had three sputum smears done. The first one was positive,
but the last two were negative.
Ms. Nguyen meets the first two criteria for noninfectiousness:
she has been receiving treatment for at least 2 to 3 weeks and
her symptoms have improved. However, she should be considered
infectious until she has three consecutive negative sputum smears.
- Mr. Martin started treatment for pulmonary TB in April.
His symptoms went away and his sputum smears became negative in
May. He missed his clinic appointment in June. When he returned
to the TB clinic at the beginning of August, he was coughing.
Mr. Martin may have become noninfectious in May, but it appears
that he may be infectious again. He is coughing, and the fact
that he missed his June appointment may indicate that he has not
been adhering to treatment. At this point, Mr. Martin should be
considered infectious. He should be evaluated for infectiousness
and nonadherence to treatment.
- What should you do?
You should suspect that this man has infectious TB. You should
work with the clinical staff to ensure that he is evaluated for
TB quickly. In the meantime, the man should be given a surgical
mask, instructed to keep it on, and asked to cover his mouth and
nose when coughing or sneezing. He should be placed in an area
away from other patients right away.
5.3. You are sent to deliver directly observed therapy
to a woman who started treatment last week for suspected pulmonary
TB. Her sputum smear results are not back yet. You are asked to
collect another sputum specimen while you are at the woman's home.
- What precautions should you take?
First, you should instruct the patient to cover her mouth and
nose when she coughs or sneezes. Second, because the patient may
be infectious, you should wear a personal respirator when visiting
her home. Third, you should collect the sputum specimen in a well-ventilated
area (preferably outdoors), away from other household members.
(Ideally, sputum specimens should be collected in a special isolation
room or booth.) Fourth, because you visit TB patients at home
as part of your job, you should participate in a TB screening
and prevention program through your employer.
Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination - http://www.cdc.gov/tb
Please send comments/suggestions/requests
CDC/Division of Tuberculosis Elimination
Communications, Education, and Behavioral Studies Branch
1600 Clifton Rd., NE - Mailstop E-10, Atlanta, GA 30333