(Facility) IHS Chest Clinic Guidelines
Latent Tuberculosis Infection
Who to test
- Contact of a person with active pulmonary tuberculosis (TB) disease
- Person with suspected active TB disease
- Chest X-ray consistent with healed TB and never treated
- Immunosuppressed: HIV, transplant, prolonged steroid treatment, treatment with anti-TNF agents.
- Certain conditions: Diabetes mellitus (DM), chronic kidney disease (CKD), low body weight (10% below ideal), silicosis, gastrectomy, adrenoleukodystrophy (ALD).
How to test
- If available, the Interferon Gamma Release Assay (IGRA) testing is preferred over the Tuberculin Skin Test (TST) if age over 5 years old meeting some of these criteria:
- Likely to be infected with TB
- Low or intermediate risk of disease progression
- TB testing is deemed to be warranted
- History of BCG or have received BCG vaccination
- Unlikely to return to have a skin test read
- Low risk persons who do not meet the criteria above, are tested anyway, and are found to be IGRA or TST positive should have a confirmatory test and only be considered to be TB infected if both tests are positive
Who to treat
--do not treat every positive TST or IGRA patient. Only treat those with these risk factors:
- Persons at personal risk for exposure to TB
- These two groups are at risk
- Health Care personnel with direct patient contact (doctors, nurses, pharmacists, radiology and lab techs, custodians, food services, clinic secretaries, etc.)
- Residential Congregate Setting facility employees and residents (Long Term Care Facilities, corrections facilities, homeless shelters, etc.)
- Persons in this category should be screened once at the time of hire and not Only Health Care Personnel with high risk of exposure such as pulmonologists and respiratory therapists or those working in a unit where tuberculosis has been spread before require annual testing.
- Health Care Personnel are considered at risk for tuberculosis if they resided for 1 or more months in a country with a high rate of TB or are immunosuppressed (HIV, transplant, TNF antagonist/steroid Rx) or are a close contact of a case of infectious tuberculosis since the last test. These personnel require treatment for LTBI if either the TST or the IGRA is positive.
- Health Care personnel who are asymptomatic and not high risk should be treated for LTBI only if both the TST and the IGRA are positive.
- These two groups are at risk
- Patients at personal risk for reactivating TB:
- 5 mm TST cutoff:
- HIV positive
- Contact of active TB case
- Fibrotic changes on Chest X-Ray consistent with prior TB
- Immunosuppressed (>15 mg prednisone/d for >1 month, received an organ transplant, TNF-alpha inhibitor, etc.). Some experts recommend sending an IGRA in addition to performing a TST and Chest X-ray on patients who are being prescribed a TNF alpha inhibitor
- 10 mm TST cutoff:
- Recent immigrant
- Injectable drug use
- Resident at jail, nursing home, hospital, shelter
- DM, CKD, lymphoma/leukemia, unexplained weight loss, silicosis, gastrectomy, age <4 years old, ALD
- IGRA positive with any of the above risk factors
- 5 mm TST cutoff:
How to treat Latent TB
Preferred Adult Regimens
- First choice: A twelve-week course of isoniazid (INH) 900 mg PO weekly and rifapentine 900 mg PO weekly (750 mg weekly if <50 kg) is the IHS combination of
- Alternate regimens:
- Rifampin 600 mg PO daily for 4 months preferred for patients with liver
- INH 300 mg PO daily for 9 months preferred for HIV positive patients who are taking antiretroviral medications that have clinically significant interactions with rifampin or rifapentine.
- Special considerations>
- Supplement INH with pyridoxine 50 mg PO daily
- INH can be given 900 mg PO 2 or 3 times a week as DOT
- Rifampin cannot be given intermittently like INH
Consider Directly Observed Therapy (DOT) in most patients to ensure adherence to the treatment regimen, eradication of disease, and safety of the patient.
Monitoring for toxicity
- Monitor the patient for symptoms of toxicity and physical exam monthly
- INH: rash, neuropathy, N/V, anorexia, jaundice, lupus-like illness
- Rifampin/rifapentine: rash, flu-like illness, jaundice, bleeding
- Monitor LFTs at baseline and periodically for patients if the patient:
- Has underlying hepatic disease (hepatitis, cirrhosis)
- Has HIV
- Is pregnant or postpartum within 3 months
- Consumes alcohol regularly
- Is taking other medications with potential hepatotoxicity
- If patient has risks for liver disease or has abnormal liver function tests (LFT)s at baseline, monitor the LFTs and CBC monthly (do not rely on symptoms and signs alone due to the high prevalence of non-alcoholic steatohepatosis (NASH) and ALD in this population)
- Testing is recommended any time during treatment if the patient has symptoms suggestive of hepatitis (e.g., fatigue, weakness, malaise, anorexia, nausea, vomiting, abdominal pain, pale stools, brown urine, chills, or jaundice).