The Canadian Tuberculosis Standards: 8th Edition
Here are the highlights:
The overall incidence of tuberculosis (TB) remains low, but foreign-born individuals and Canadian Indigenous people are disproportionately affected.
Screening for high-risk individuals must include chest radiography.
Confirm diagnosis with acid-fast bacilli (AFB) microbiology or nucleic acid amplification tests (NAATs). We do NOT recommend monitoring response to treatment or determine contagiousness with NAAT.
Tuberculin skin test (TST) and interferon gamma release assays (IGRA) are not sufficient for diagnosis, but they have special uses. - IGRA is preferred in pediatrics and those who have received the BCG vaccine - TST is preferred for serial testing or when assessing risk of new infection - Combining both increases sensitivity in high-risk individuals
*Up to 30% of children may have negative TST or IGRA so clinical context is important.
Avoid monotherapy! Minimum 3 drugs are recommended in the intensive phase (first 2 months), ideally Isoniazid, Rifampin, Pyrazinamide and Ethambutol.
When treating children, daily therapy is strongly recommended.
Ethambutol is now routinely used in initial empiric therapy in infants and children.
Drug-resistant TB (DR-TB) is uncommon and is mainly mono-resistance to Isoniazid or Pyrazinamide.
Use phenotypic drug susceptibility testing (DST) and rapid molecular tests to guide therapy. - For mono-isoniazid resistance, late generation fluoroquinolones (levofloxacin) are preferred. - For multi drug resistant TB (MDR-TB), initial regimens should include Levofloxacin AND Bedaquiline AND Linezolid AND Clofazimine AND Cycloserine.
Monitor for recurrence in for 1-2 years post-therapy.
The recommended first-line TB preventive treatment (TPT) can be: - once weekly Rifapentine and Isoniazid for 3 months (3HP) - Daily Rifampin for 4 months (4R)- preferred in children under 2 years
Extend therapy for 12 months for extra-pulmonary TB.
*NEW: For TB meningitis, use high dose Rifampin (>15 mg/kg/day PO/IV) during intensive phase.
*NEW: For pleural TB, routine corticosteroid or therapeutic thoracentesis is not recommended. However, corticosteroids can be considered for TB pericarditis in HIV-negative patients.
All foreign-born persons immigrating to Canada undergo screening including chest radiography and are subsequently treated if found with active TB. They must be followed for reactivation based on provincial/territorial guidelines.
Baseline TST is recommended for all healthcare workers, but periodic testing is NO LONGER routinely recommended.