TB

For any questions or concerns regarding Tuberculosis, please consider consulting one of the Chest Clinic providers - See [|Amion]for the doctor on call. Please contact Contra Costa Public Health Communicable Disease Programs directly to report a case of TB or for any other questions: 925-313-6740. toc

**Screening **
Patients with symptoms suspicious for active TB (cough >3 weeks, fever, weight loss, loss of appetite, fatigue, hemoptysis) should be evaluated for active TB with a chest x-ray. **Do not wait for result of TST, QFT or IGRA!** If the chest x-ray is abnormal consistent with TB, order sputum AFB x3 with at least one TB PCR. Contact the TB med consult MD listed on amion.com or the TB Control Program at 925-313-6740 for assistance.
 * Who to Screen: ** //Asymptomatic// patients at risk of TB exposure and patients at risk of progressing to active TB if exposed.


 * How to Screen **: Use the following risk assessment questionnaires (adult and pediatric). If your patient has any of the listed risk factors, test for latent TB infection.

**Risk Assessment for Adults: **

 * **Foreign-born ** from a country with an elevated TB rate (includes countries other than the United States, Canada, Australia, New Zealand, or Western and North European countries).
 * o Prioritize patients with at least one medical risk for progression:
 * diabetes mellitus
 * smoker within past 1 year
 * end stage renal disease
 * leukemia or lymphoma
 * silicosis
 * cancer of head or neck
 * <span style="font-family: Arial,sans-serif; font-size: 10pt;">intestinal bypass/gastrectomy
 * <span style="font-family: Arial,sans-serif; font-size: 10pt;">chronic malabsorption
 * <span style="font-family: Arial,sans-serif; font-size: 10pt;">body mass index ≤20
 * <span style="font-family: Arial,sans-serif; font-size: 10pt;">history of chest x-ray findings suggestive of previous or inactive TB (no prior treatment). Includes fibrosis or non-calcified nodules, but does not include solitary calcified nodule or isolated pleural thickening. In addition to LTBI testing, evaluate for active TB disease


 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">Immunosuppression **<span style="font-family: Arial,sans-serif; font-size: 10pt;">, current or planned
 * o <span style="font-family: Arial,sans-serif; font-size: 10pt;">HIV infection, organ transplant recipient, treated with TNF-alpha antagonist (e.g., infliximab, etanercept, others), steroids (equivalent of prednisone ≥15 mg/day for ≥1 month) or other immunosuppressive medication


 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">Close contact **<span style="font-family: Arial,sans-serif; font-size: 10pt;"> to someone with infectious TB disease at any time.

**<span style="font-family: Arial,sans-serif; font-size: 10pt;">Risk Assessment for Children: **

 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">Foreign-born **<span style="font-family: Arial,sans-serif; font-size: 10pt;"> from a country with an elevated TB rate (includes countries other than the United States, Canada, Australia, New Zealand, or Western and North European countries).


 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">Immunosuppression **<span style="font-family: Arial,sans-serif; font-size: 10pt;">, current or planned
 * o <span style="font-family: Arial,sans-serif; font-size: 10pt;">HIV infection, organ transplant recipient, treated with TNF-alpha antagonist (e.g., infliximab, etanercept, others), steroids (equivalent of prednisone ≥15 mg/day for ≥1 month) or other immunosuppressive medication


 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">Close contact **<span style="font-family: Arial,sans-serif; font-size: 10pt;"> to someone with infectious TB disease at any time.


 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">Foreign travel or residence **<span style="font-family: Arial,sans-serif; font-size: 10pt;"> of at least one month consecutively in a country with an elevated TB rate (includes countries other than the United States, Canada, Australia, New Zealand, or Western and North European countries).

**<span style="font-family: Arial,sans-serif; font-size: 13.5pt;">Testing **
<span style="font-family: Arial,sans-serif;">Highlights:
 * <span style="font-family: Arial,sans-serif; font-size: 10pt;">All tests for latent TB are considered to be **equivalent**, though there are some advantages and disadvantages in certain situations.
 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">Tests for latent TB cannot be used to rule out active TB disease! **<span style="font-family: Arial,sans-serif; font-size: 10pt;"> 75-80% of patients with active disease will have a negative TST or IGRA.
 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">TST **<span style="font-family: Arial,sans-serif; font-size: 10pt;"> (tuberculin skin test): More likely to be false positive in a foreign born person with history of BCG vaccine.
 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">IGRA (Quantiferon): Preferred Test, if foreign born or history of BCG vaccine. **<span style="font-family: Arial,sans-serif; font-size: 10pt;"> No false positives due to BCG vaccine. Can be used in anyone over the age of 2 years.
 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">IGRA (T-SPOT): **<span style="font-family: Arial,sans-serif; font-size: 10pt;"> May be more sensitive in children 2-4 years of age, and immunocompromised patients.
 * **<span style="font-family: Arial,sans-serif; font-size: 10pt;">Please consult with peds ID or the TB program for children <2 years old. **

<span style="font-family: Arial,sans-serif; font-size: 10pt;">The tuberculin skin test (TST) measures delayed-type hypersensitivity reaction to PPD (purified protein derivative – basically smashed up TB bacteria) that is injected intradermally. The reaction is measured in mm of induration 48-72 hours after placement. The TST can react to antigens present in BCG vaccine so can give a false positive result in BCG vaccinated patients.

<span style="font-family: Arial,sans-serif; font-size: 10pt;">Interferon gamma release assays (IGRAs) measure the amount of interferon gamma release by circulating lymphocytes in response to TB-specific antigens. IGRAs are the preferred test for foreign born patients with a history of BCG vaccine. The antigens used in IGRAs do not cross react with BCG vaccine, as can happen with the TST.

<span style="font-family: Arial,sans-serif; font-size: 10pt;">The most commonly used IGRA, Quantiferon, measures the amount of interferon gamma released in a sample of whole blood while the T-spot TB test separates out a defined number of lymphocytes before exposing them to the antigens in the assay. The T-spot TB is therefore most often used in children and immunocompromised patients with low levels of circulating lymphocytes or in patients with indeterminate results with the QFT due to low mitogen (the positive control used in the assay). =

=

Evaluation of a Positive LTBI Test

 * <span style="font-family: Arial,sans-serif; font-size: 10pt;">Conflicting TST and IGRA test results are common. Try to choose the appropriate test in advance and go with that result (e.g. don’t do a follow up QFT after a positive TST in a person without BCG vaccine). For individuals at high risk of progression to active TB, consider any positive test as an indication for LTBI treatment.
 * <span style="font-family: Arial,sans-serif; font-size: 10pt;">Obtain CXR and do a symptom review (prolonged cough, fever, fatigue, night sweats, weight loss or loss of appetite). If negative, offer treatment for Latent Tuberculosis Infection (LTBI).

Treatment Regimens:
Shorter regimens for treating latent TB infection have been shown to be as effective as 9 months of isoniazid and are more likely to be completed. Use of these shorter regimens is preferred in most patients, although the 12 week regimen is not recommended for children <2 years of age, patients on antiretroviral medications, or pregnant women. 25 mg/kg weekly rounded to nearest 50/100 mg in patients aged 2–11 years old
 * Drugs || Frequency || Duration || Dosing || Comments ||
 * **Isoniazid/rifapentine** || Once weekly || 12 weeks || Isoniazid:

15 mg/kg weekly rounded to nearest 50/100 mg in patients aged ≥ 12 years old (900 mg max)

Rifapentine: 10.0 – 14.0 kg: 300 mg weekly 14.1 – 25.0 kg: 450 mg weekly 25.1 – 32.0 kg: 600 mg weekly 32.1 – 49.9 kg: 750 mg weekly ≥ 50.0 kg: 900 mg (max) weekly || Adults and Children ≥ 2 years old Should not be used in HIV patients on ARVs due to drug-drug interactions with rifapentine. Should not be used in pregnant women due to lack of safety data. || Children: 10–20 mg/kg (max 600 mg) daily || Many drug-drug interactions, may not be suitable for HIV patients on ARVs. || Children: not recommended || May be a substitute for rifampin for adult patients on medications that interact with rifampin. || Children: 10–15 mg/kg (max 300 mg) daily || Administer with pyridoxine 25 mg daily in patients with increased risk of peripheral neuropathy (e.g., diabetes, alcoholism, renal failure, HIV, pregnancy, breast feeding). ||
 * **Rifampin** || Daily || 4 months || Adults: 10 mg/kg (max 600 mg) daily
 * **Rifabutin** || Daily || 4 months || Adults: 5 mg/kg (max 300 mg) daily
 * **Isoniazid** || Daily || 9 months || Adults: 5 mg/kg (max 300 mg) daily

Chest Clinic Referrals
The following patients with latent TB should still be referred to Chest Clinic and reported to Public Health via CMR:
 * Children < 5 years old
 * Patients with complicated LTBI: e.g. the frail elderly, patients with multiple co-morbidities, patients with prior treatment where it is unclear if re-treatment is necessary, patients on multiple medications, etc
 * LTBI patients whom are identified as contacts to an active TB suspect or case. If a patient gives history of recent TB contact (unless referred to you by PHN), obtain the name, DOB, and address of suspected source case, and contact CCPH at 925-313-6740 to determine whether the patient is a true TB contact.

LTBI Nurse Referrals

 * The initial CXR, counseling of the patient, a symptom review, and treatment plan must be established by the referring provider.
 * The LTBI nurse can follow patients for LTBI treatment who are on Isoniazid/Rifapentine, Rifampin, Rifabutin, or Isoniazid alone.
 * The LTBI nurse acts to coordinate care for all patients over 5 years of age receiving LTBI treatment. For patients being started on LTBI treatment, provide them with one month worth of their medication without refills. The LTBI nurse will then make regular calls to the patient to ensure they are adherent to their treatment and tolerating their medication(s).

Additional Resources
LTBI Follow-up Policy 4104 (iSite) CDC's Latent Tuberculosis Infection: A Guide for Primary Health Care Providers Contra Costa Public Health Communicable Disease Programs: 925-313-6740 or on the web. This page has been edited {$pagerevisions} times. The last modification was made by user:{$revisioneditor} on {$revisiondate}