American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended treatment regimen for latent tuberculosis infection?

1. Daily rifampin for 9 months

2. Daily isoniazid with pyridoxine for 9 months

3. Weekly isoniazid and rifapentine for 3 months

4. Daily ethambutol for 6 months

The correct answer is: Daily isoniazid with pyridoxine for 9 months

The recommended treatment regimen for latent tuberculosis infection involves administering daily isoniazid for a duration of 9 months, often accompanied by pyridoxine (vitamin B6) to mitigate the risk of peripheral neuropathy, which can be a side effect of isoniazid. This regimen is widely endorsed by public health organizations because it effectively reduces the risk of progression from latent infection to active tuberculosis disease. Isoniazid works by inhibiting the synthesis of mycolic acids, which are essential components of the mycobacterial cell wall, thereby targeting the dormant TB bacteria that reside in the host body during latent infection. The 9-month duration is well-supported by clinical trials showing a significant reduction in the incidence of active TB among those treated compared to untreated individuals. While other regimens exist, such as the 3-month regimen of weekly isoniazid and rifapentine, these have certain contraindications and may not be suitable for all patients. The significance of isoniazid as a standard treatment lies in its long-standing use and research backing its effectiveness and safety profile over a 9-month course. This understanding is paramount for healthcare providers when they are deciding on treatment strategies for patients with latent tuberculosis infection to ensure