Latent TB Infection: Guide for Diagnosis and Treatment

Special Considerations

Contacts

Contacts are those with recent exposure to a person with known or suspected infectious TB (e.g., pulmonary or laryngeal TB with positive sputum smear). They should be evaluated immediately for LTBI and TB disease. If the TST or IGRA result is positive, the guidance below should be followed. Those who have negative results should be retested in 8–10 weeks after exposure has ended. However, if the chest radiograph is normal, LTBI treatment should be initiated in TST-negative children ≤ 5 years of age (note: some TB control programs may use a different age cutoff) and in immunocompromised persons of all ages who have negative TST or IGRA results. Treatment should be continued until the results of the second test and other medical evaluation are known. For some high-risk contacts, a full course of LTBI treatment may be recommended even in the absence of a positive TST or IGRA result. Consult with your local TB control program about the management of such contacts.

If person is exposed to known drug-susceptible TB or drug susceptibility is unknown:
- Positive TST or IGRA result → Treat regardless of age with isoniazid (INH) or INH and RPT for those over 12 years of age
If person is exposed to known isoniazid-resistant TB:
- Positive TST or IGRA result → Treat with rifampin (RIF) for 4 months
If person is exposed to known multidrug-resistant (MDR) TB:
- Positive TST or IGRA result → Consult an expert in the treatment of MDR TB
In general, TST or IGRA-positive contacts who can provide written documentation of prior adequate treatment for LTBI do not need to be retreated. Retreatment may be indicated for persons at high risk of becoming reinfected and progressing to TB disease (e.g., young children and immunosuppressed persons).

HIV-Infected Individuals

HIV-infected individuals receiving antiretroviral therapy (ART) should be treated with a 9-month regimen of INH.

Rifampin (RIF) is contraindicated in HIV-infected persons being treated with certain combinations of antiretroviral drugs. In those cases, rifabutin may be substituted for RIF.
HIV-infected individuals who are otherwise healthy and are not taking ART can be considered for the 12-dose regimen.
If the test for TB infection is negative, consider treatment if HIV-infected person had recent exposure to infectious TB, as discussed above.

Pregnancy

After TB disease is excluded, consider immediate treatment for LTBI if the woman is HIV infected or a recent contact, and monitor.
In the absence of risk factors, wait until after the woman has delivered to avoid administering unnecessary medication during pregnancy
INH daily or twice weekly (using DOT) is the preferred regimen.
Supplementation with 10-25 mg/d of pyridoxine (vitamin B6) is recommended.
The 12-dose regimen is not recommended for pregnant women or women expecting to become pregnant during the treatment period.
There is potential for an increased risk of hepatotoxicity during pregnancy and the first 2-3 months of the post-partum period.
Consider delaying treatment for LTBI until 2-3 months post-partum unless there is a high risk of progression to TB disease (e.g., HIV infected, recent contact).

Breastfeeding

Breastfeeding is not contraindicated in women taking INH.
Supplementation with 10-25 mg/d of pyridoxine (vitamin B6) is recommended for nursing women and for breastfed infants.
The amount of INH in breast milk is inadequate for treatment of infants with LTBI.

Infants and Children

Infants and children under 5 years of age with LTBI have been recently infected and, therefore, are at high risk for progression to disease.
Testing of adults in close social contact with the child may be warranted to determine whether a person with infectious TB disease can be found. Consult with your local TB control program.
Risk of INH-related hepatitis in infants, children, and adolescents is minimal.
Routine monitoring of serum liver enzymes is not necessary unless the child has risk factors for hepatotoxicity.
The preferred regimen for children aged 2 to 11 years is 9 months of daily INH.
The 12-dose regimen is not recommended for children younger than 2 years of age.
DOT should be considered for children of all ages, and is strongly recommended when the 12-dose regimen is used.

Additional Notes of Importance

Old fibrotic lesions can represent previous TB disease. Persons with old fibrotic lesions with TST result of ≥5 mm of induration or a positive IGRA result and negative culture should be treated for LTBI.
Calcified solitary pulmonary nodules, calcified hilar lymph nodes, and apical pleural capping represent healed primary M. tuberculosis infection and do not increase the risk of TB disease. The decision to treat for LTBI would be the same as for a person with a normal chest radiograph.
The 12-dose regimen is not recommended for people presumed to be infected with INH or RIF-resistant M. tuberculosis.
All doses of the 12-dose regimen should be given by DOT.

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Thứ Bảy, 9 tháng 1, 2016

Latent TB Infection: Special Considerations