An 8-year-old girl is brought to the office by her mother for evaluation of possible tuberculosis (TB). The patient's younger brother was recently diagnosed with active pulmonary TB, which he contracted from their grandmother. The patient has been in close contact with her brother but has had no fever, night sweats, cough, anorexia, or weight loss. She had a negative TB skin test at the time of immigration from Southeast Asia 2 years ago. The patient has not received the bacille Calmette-Guérin vaccine but is up to date with other recommended vaccinations. Vital signs are within normal limits and physical examination shows no abnormalities. Interferon-gamma release assay is positive and chest radiography is normal. Cultures from a gastric aspirate of her younger brother show acid-fast bacilli that are resistant to isoniazid (INH) but are sensitive to other anti-TB drugs. Which of the following is the most appropriate management for this patient?

Question

An 8-year-old girl is brought to the office by her mother for evaluation of possible tuberculosis (TB).  The patient's younger brother was recently diagnosed with active pulmonary TB, which he contracted from their grandmother.  The patient has been in close contact with her brother but has had no fever, night sweats, cough, anorexia, or weight loss.  She had a negative TB skin test at the time of immigration from Southeast Asia 2 years ago.  The patient has not received the bacille Calmette-Guérin vaccine but is up to date with other recommended vaccinations.  Vital signs are within normal limits and physical examination shows no abnormalities.  Interferon-gamma release assay is positive and chest radiography is normal.  Cultures from a gastric aspirate of her younger brother show acid-fast bacilli that are resistant to isoniazid (INH) but are sensitive to other anti-TB drugs.  Which of the following is the most appropriate management for this patient?

Quizplus · Accepted Answer

Explanation: This patient with a positive interferon-gamma release assay has no symptoms or chest x-ray findings of active tuberculosis (TB), indicating latent tuberculosis infection (LTBI). Patients with LTBI receive empiric treatment without microbial isolation. As such, providers must rely on drug-susceptibility results of the likely source case (if available) to help guide treatment decisions. This patient likely acquired the infection from close contact with her brother. He has known pulmonary TB with an isoniazid-resistant strain (in children, gastric lavage sampling is often performed instead of induced sputum). As such, first-line therapy with daily isoniazid for 9 months is unlikely to be effective (Choice D). Instead, this patient should receive alternate therapy with daily rifampin for 4-6 months. (Choice A) Active pulmonary TB is often treated with multidrug therapy consisting of isoniazid, rifampin, pyrazinamide, and ethambutol for 2 months followed by isoniazid and rifampin for 4 months. Active pulmonary TB is marked by symptoms (eg, cough >3 months, weight loss, fever) and/or chest x-ray findings (eg, cavitation, infiltrate). This asymptomatic patient with a normal chest x-ray has LTBI, not active TB. (Choice B) Patients with a positive tuberculosis screening test usually have positive testing for life. Waiting 2 months to repeat an interferon gamma release assay would provide little clinical information and cause an unnecessary treatment delay. (Choice C) Sputum (or gastric lavage) acid-fast bacilli testing and mycobacterial culture are required only for patients with active pulmonary TB. This patient has LTBI, not active pulmonary TB. Educational objective: Children with latent tuberculosis infection require treatment to prevent conversion to active disease. Daily isoniazid for 9 months is the standard of care. If isoniazid resistance is suspected, the best alternate therapy is daily rifampin for 4-6 months.

An 8-Year-Old Girl Is Brought to the Office by Her