TB Facts for Health Care Workers
2006
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Prevention of Tuberculosis
The main purpose of treating LTBI is to prevent it from progressing
to clinically active TB disease. Therefore, persons with positive
tuberculin skin test results who do not have clinically active disease
should be evaluated for treatment of LTBI.
Candidates for Treatment
of Latent TB Infection
Persons in the following high-risk groups should be considered
for treatment of LTBI if their reaction to the tuberculin skin test
is >5 mm of induration:
- Persons with HIV infection *
- Close contacts of a TB case*
- Patients who have had organ transplants, and other immunosuppressed
patients (receiving the equivalent of >15 mg/day of
prednisone for >1 month)
- Persons with fibrotic changes on chest radiograph consistent
with old TB disease
- Persons receiving specialized treatment
for rheumatoid arthritis or Crohn’s disease
Persons in the following high-risk groups should be considered
for treatment of LTBI if their reaction to the tuberculin skin test
is >10 mm of induration:
- Recent arrivals to the United States (<5
years) from high-prevalence countries
- Persons who inject illicit drugs
- Residents and employees of high-risk congregate settings
- Mycobacteriology laboratory personnel
- Persons with medical conditions that make them high risk (see
Table 1, "Summary of interpretation of tuberculin skin-test
results")
- Children <4 years of age, or children and adolescents exposed
to adults in high-risk categories
In general, persons with no known risk factors for TB should not
be tested for LTBI. However, testing is occasionally performed among
certain population groups for surveillance purposes or where a case
of TB could result in extensive transmission. If testing is performed
in these populations, they may be considered for treatment of LTBI
if their reaction to the tuberculin test is >15 mm of
induration. This group should be given a lower priority for prevention
efforts than the groups listed previously.
*In some circumstances, persons in these categories
may be evaluated for the treatment for LTBI in the absence of a
positive TST. Treatment for LTBI should be given after TB disease
has been ruled out. Some close contacts who have a negative tuberculin
skin test reaction (< 5 mm of induration) should be evaluated
for treatment of LTBI. These contacts include children less than
5 years of age, immunosuppressed people, and others who may develop
TB disease quickly after infection.
Close contacts who have a negative reaction to an
initial skin test should be retested 8 to 10 weeks after they were
last exposed to TB. If receiving treatment for LTBI, treatment may
be discontinued if the skin test result is again negative and if
the person is no longer exposed to TB.
However, close contacts known to have or suspected
of having HIV infection and other immunocompromised persons should
be given treatment for LTBI regardless of their skin test reaction.
Because of their age, infants and young children
with a positive skin test are known to have been infected recently,
and are at high risk of their infection progressing to disease.
Infants and young children are also more likely than older children
and adults to develop life-threatening forms of TB disease.
Children <5 years of age who are close contacts
to someone with infectious TB should receive treatment for LTBI
even if the tuberculin skin test result and chest radiograph do
not suggest TB. A second tuberculin test should be placed 8–10 weeks
after the last exposure to infectious TB. Treatment of LTBI can
be discontinued at that time if all of the following conditions
are met:
- The second tuberculin test is negative.
- The second test was performed at least 10 weeks
after the child was last exposed to infectious TB.
- The child is at least 6 months of age.
Regimens for the Treatment of Latent TB Infection
For persons suspected of having LTBI, treatment of LTBI should
not begin until TB disease has been excluded. Persons suspected
of having TB disease should receive the recommended multidrug regimen
for treatment of disease until the diagnosis is confirmed or ruled
out.
Although regimens are broadly applicable, there are modifications
that should be considered under special circumstances (i.e., HIV
infection, suspected drug resistance, pregnancy, or treatment of
children). Listed in Table 2 are the regimens; please refer to
Targeted
Tuberculin Testing and Treatment of Latent TB Infection for
detailed information for the treatment of LTBI.
Table 2: Drug Regimens for the Treatment of LTBI
Drugs |
Duration (months) |
Dosing Frequency |
Minimum Doses |
Isoniazid |
9 |
Daily |
270 |
Twice Weekly |
76 |
Isoniazid |
6 |
Daily |
180 |
Twice Weekly |
52 |
Rifampin |
4 |
Daily |
120 |
Rifampin/Pyrazinamide |
Generally should not
be offered for treatment of LTBI |
Owing to the reports of severe liver injury and deaths, CDC and
ATS now recommend that the combination of rifampin (RIF) and pyrazinamide
(PZA) should generally not be offered for the treatment of LTBI.
If the potential benefits substantially outweigh the demonstrated
risk of severe liver injury and death associated with this regimen
and the patient has no contraindications, a TB/LTBI expert should
be consulted prior to the use of this regimen. (Clinicians should
continue the appropriate use of RIF and PZA in multidrug regimens
for the treatment of TB disease.)
Monitoring
Isoniazid (INH) or Rifampin Alone
Routine laboratory monitoring during treatment of LTBI is indicated
only for those whose baseline tests suggest a liver disorder and
for other persons with a risk of hepatic disease. Laboratory testing
should be performed to evaluate possible adverse reactions that
occur during the treatment regimen.
Rifampin/Pyrazinamide or Rifabutin/Pyrazinamide
A TB/LTBI expert should be consulted prior to the use of this regimen.
CDC is collecting reports of severe adverse events (i.e., leading
to hospital admission or death) in persons receiving any treatment
regimen for LTBI. Report possible cases to the Division of Tuberculosis
Elimination by calling (404) 639-8401 or by e-mail to Lmanangan@cdc.gov.
To ensure that persons in high-risk groups adhere to therapy, INH
can be given twice weekly at a dosage of 15 mg/kg, up to a maximum
of 900 mg, using directly observed therapy (DOT) of LTBI. DOT refers
to the observation by a health care provider of patients as they
ingest anti-TB medications.
The method of DOT of LTBI should be based on a thorough
assessment of each patient’s needs, living and employment
conditions, and preferences. The patient and provider should
agree on a method that ensures the best possible DOT of LTBI
routine and that maintains the patient’s confidentiality. |
Situations in which patients not receiving DOT for LTBI miss appointments
or demonstrate other nonadherent behavior should be brought to the
attention of the appropriate public health officials. These patients
should be considered for DOT of LTBI.
Persons given treatment for LTBI should be monitored monthly for
drug side effects, especially signs and symptoms of hepatitis.
Last Reviewed: 05/18/2008 Content Source: Division of Tuberculosis Elimination
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
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