What are the guidelines for tuberculosis (TB) screening and treatment?

From the Guidelines

Tuberculosis screening and treatment guidelines recommend targeted testing for high-risk individuals rather than universal screening, with the most recent guidelines from 2020 suggesting short-course rifamycin-based treatment regimens as the preferred option for latent TB infection (LTBI) treatment. Screening typically involves a tuberculin skin test (TST) or interferon-gamma release assay (IGRA) blood test, with positive results requiring chest X-rays to distinguish between latent TB infection (LTBI) and active disease 1. For LTBI, recommended treatment regimens include isoniazid (INH) for 6-9 months, rifampin for 4 months, or the shorter 3-month regimen of weekly INH plus rifapentine, with the 2020 guidelines preferring the shorter rifamycin-based regimens due to their effectiveness, safety, and high treatment completion rates 1.

Key Points for Tuberculosis Screening and Treatment

• Targeted testing for high-risk individuals, such as those living with HIV, contacts of pulmonary TB cases, and patients initiating anti-tumour necrosis factor treatment, is recommended 1.
• Either TST or IGRA can be used to test for LTBI, with chest radiography performed before LTBI treatment to rule out active TB disease 1.
• Treatment options for LTBI include 6-month daily isoniazid, 9-month daily isoniazid, 3-month weekly rifapentine plus isoniazid, 3–4 month daily isoniazid plus rifampicin, or 3–4 month daily rifampicin alone, with the 2020 guidelines recommending short-course rifamycin-based regimens as the preferred option 1.
• Active TB requires a multi-drug approach, typically with a 2-month intensive phase of isoniazid, rifampin, pyrazinamide, and ethambutol, followed by a 4-month continuation phase of isoniazid and rifampin, for a total of 6 months 1.
• Drug susceptibility testing is essential to guide therapy, as multi-drug resistant TB requires specialized regimens 1.
• Treatment should be directly observed to ensure adherence, and patients should be monitored for drug side effects, particularly hepatotoxicity 1.

Recommendations for High-Risk Groups

• Systematic testing and treatment of LTBI is recommended for people living with HIV, adult and child contacts of pulmonary TB cases, patients initiating anti-tumour necrosis factor treatment, patients receiving dialysis, patients preparing for organ or haematological transplantation, and patients with silicosis 1.
• Systematic testing and treatment of LTBI should be considered for prisoners, healthcare workers, immigrants from high TB burden countries, homeless persons, and illicit drug users, according to TB epidemiology and resource availability 1.

From the FDA Drug Label

For preventive therapy of tuberculous infection and treatment of tuberculosis, it is recommended that physicians be familiar with the following publications: (1) the recommendations of the Advisory Council for the Elimination of Tuberculosis, published in the MMWR: vol 42; RR-4,1993 and (2) Treatment of Tuberculosis and Tuberculosis Infection in Adults and Children, American Journal of Respiratory and Critical Care Medicine: vol 149; 1359-1374,1994. The current recommendation of the CDC for drug-susceptible disease is to use a six-month regimen for initial treatment of active tuberculosis, consisting of isoniazid, rifampin and pyrazinamide given for 2 months, followed by isoniazid and rifampin for 4 months.

The guidelines for tuberculosis (TB) screening are not explicitly stated in the provided drug labels. However, for treatment, the recommended regimens include:

• A six-month regimen for initial treatment of active tuberculosis, consisting of isoniazid, rifampin, and pyrazinamide given for 2 months, followed by isoniazid and rifampin for 4 months 2 3.
• Three regimen options for the initial treatment of tuberculosis in children and adults, which include isoniazid, rifampin, pyrazinamide, and optional ethambutol or streptomycin 2. Treatment decisions should be individualized, especially for patients with HIV infection or drug-resistant disease 2 3.

From the Research

Guidelines for Tuberculosis Screening

• The Advisory Council for the Elimination of Tuberculosis recommends that screening for TB infection should not be given preference over high priority TB prevention and control activities, especially identifying and completely treating all persons who have active TB as well as conducting prompt, effective contact investigation 4.
• The National TB and Leprosy Control Program (NTLP) symptom-based tuberculosis screening tool can be used to identify HIV-infected patients eligible for isoniazid preventive therapy, with a sensitivity and specificity of 71.4% and 75.9%, respectively 5.
• Sputum examination can be used to detect TB suspects with clinical symptoms, and can find out more cases with active disease (21.2%) than chest X-ray screening alone 6.

Treatment of Tuberculosis

• Standard TB treatment includes an initial regimen containing drugs that are both rapidly bactericidal (isoniazid) and sterilizing (rifampin and pyrazinamide), and ethambutol to help prevent the emergence of drug resistance 7.
• The administration of isoniazid, rifampicin, ethambutol, and pyrazinamide (HREZ) for 2 months and HR for 4 additional months is recommended in new cases of TB, except in cases of meningitis or spinal TB with neurological involvement 8.
• Treatment control is one of the most important activities in TB management, and an antibiogram to first-line drugs should be performed in all initial isolations of new patients 8.

Diagnosis of Tuberculosis

• Pulmonary TB should be suspected in patients with respiratory symptoms longer than 2-3 weeks, and immunosuppression may modify clinical and radiological presentation 8.
• Chest X-ray shows very suggestive, albeit sometimes atypical, signs of TB, and complex radiological tests (CT scan, MR) are more useful in extrapulmonary TB 8.
• Bacilloscopy and liquid medium cultures are indicated in all cases, and genetic amplification techniques are coadjuvant in moderate or high TB suspicion 8.
• The Tuberculin Skin Test (TST) is positive in TB infection when >or=5mm, and Interferon-Gamma Release Assays (IGRA) are recommended in combination with TST 8.