Latent TB Treatment for Patient Starting Adalimumab
Yes, this patient with a previous positive TB test from India, BCG vaccination history, normal CXR, and no symptoms should receive latent TB treatment before starting adalimumab. 1, 2
Rationale for Treatment
Adalimumab (a TNF-α inhibitor) significantly increases the risk of TB reactivation by:
- Disrupting granulomas that contain latent TB infection 3
- Increasing TB reactivation risk approximately 5-fold 2
- Potentially causing disseminated rather than localized TB disease 1
The FDA label for adalimumab (Humira) explicitly states: "Evaluate patients for tuberculosis risk factors and test for latent infection prior to initiating HUMIRA and periodically during therapy. Treatment of latent tuberculosis infection prior to therapy with TNF blocking agents has been shown to reduce the risk of tuberculosis reactivation during therapy." 1
Risk Assessment
Several factors in this case indicate high risk:
- Origin from India (high TB prevalence area) 2
- Previous positive TB test 2
- Impending immunosuppression with adalimumab 1
The British Thoracic Society guidelines specifically note that patients from South Asia born outside the UK (which would include India) should be considered for chemoprophylaxis 2.
BCG Vaccination Considerations
While the patient has received BCG vaccination:
- BCG history does not eliminate the need for LTBI treatment when starting TNF inhibitors 2
- A positive TB test in this context should still be considered indicative of latent TB infection, even with prior BCG vaccination 1
- The FDA label states to "consider an induration of ≥ 5 mm a positive tuberculin skin test result, even for patients previously vaccinated with Bacille Calmette-Guerin (BCG)" 1
Treatment Options
The recommended treatment regimens include:
Isoniazid for 6-9 months (preferred option) 4, 2
- Lower hepatotoxicity risk compared to other regimens
- Can be started concurrently with adalimumab
Rifampin plus isoniazid for 3 months (alternative) 4
- Shorter duration may improve adherence
- Higher completion rates
- Note: Rifampin may interact with other medications
Rifampin alone for 4 months (alternative if isoniazid cannot be tolerated) 4
Monitoring During Treatment
- Baseline liver function tests before starting treatment 2
- Regular clinical assessment for symptoms of hepatotoxicity 2
- Monitor for symptoms of active TB development despite treatment 1
- Educate patient about potential side effects and importance of completing the full course 4
Important Cautions
- Despite LTBI treatment, TB reactivation can still occur in patients on adalimumab 5
- Cases of disseminated TB have been reported even after completing LTBI treatment 6, 5
- Careful monitoring for TB symptoms should continue throughout adalimumab therapy 1
Conclusion
Despite normal CXR and absence of symptoms, the combination of a positive TB test from a high-prevalence country and impending TNF-α inhibitor therapy creates a high-risk situation that warrants LTBI treatment. The benefits of preventing TB reactivation clearly outweigh the risks of LTBI treatment in this scenario.