- Pediatric tuberculosis (TB) is the disease state caused by Mycobacterium tuberculosis, an acid-fast bacillus (AFB). Pediatric TB should be regarded as a spectrum of exposure through infection to disease because progression from an infected person (exposure) to infection and disease can occur much faster (within 1 to 6 months) in children <2 years of age (occurring within the incubation of the disease stated below).
- Progression through this spectrum depends on age; such disease progression being 40–50% for children up to 2 years old, ~20% for those 2 to 4 years old, and 10–15% for those ≥5 years old. 5- to 10-year-old children are the most protected age group. Adolescence is another vulnerable age group.
- Most common route of infection is via the respiratory tract. TB is spread from a person with disease by droplet nuclei that are inhaled by other people. Infection occurs after close and prolonged contact with an adult or adolescent who has active untreated infectious disease, usually pulmonary TB, in a poorly ventilated space. However, there are people who develop TB without knowledge of an infectious contact.
- Congenital infection occurs, although rarely, in the setting of an untreated mother in the last trimester of pregnancy.
- Infection with the tubercle bacillus needs to be differentiated from disease (i.e., TB infection vs. TB disease).
- The interval between onset of TB infection (previously called “latent TB”) and TB disease is usually 10 to 12 weeks. This interval is occasionally faster than 10 weeks and, not infrequently, may be significantly longer than 12 weeks.
- Following TB exposure, the greatest chance of infection occurring (i.e., of a positive result in tests using purified protein derivative [PPD], now renamed tuberculin skin test [TST]) is within the first 2 years after infection.
- The speed of progression through the spectrum of pediatric TB (exposure–infection–disease) is age dependent for infants and children <5 years of age, (see “Description”).
- Postpubertal adolescents and immunosuppressed people including people with diabetes, HIV, chronic renal failure, the malnourished, and those taking steroids for any reason have higher risks for progression of infection to disease.
- There are now several treatment regimens available for the treatment of TB infection in the absence of TB disease. The reader is referred to the Centers for Disease Control and Prevention (CDC) Web site in the “Additional Reading” section.
- Preferred regimen is isoniazid (isonicotinic acid hydrazide [INH]), 10 to 20 mg/kg/24 h PO for 9 months or, if compliance is not anticipated, 2 times a week as direct observed therapy at 20 to 30 mg/kg, with a maximum dose of 900 mg usually administered by a school nurse, child care worker, or the local TB control program, ideally without breaks in treatment, although the patient has 12 months to complete the course. If a break occurs near the end of treatment, it need not be restarted because such treatment is ~90% effective against development of active TB for 20 years in nonimmunosuppressed children. This recommendation prevents disease in the treated patient and, as a public health measure, interrupts transmission to contacts of that infected person with 90% efficacy.
- Other drugs for latent TB when INH cannot be tolerated or case patient has INH-resistant but rifampicin-susceptible TB include 6 months of rifampin 10 to 20 mg/kg by direct observed therapy (for a total of 180 doses).
- For adults and children 12 years and older, a once-weekly 3-month course of INH and rifapentine can be considered via direct observed therapy (12 doses total).
- Bacillus Calmette-Guérin (BCG) vaccine is recommended in the United States only for infants and children who test negative to PPD and who are continually exposed to and cannot be separated from either (i) contagious adults or (ii) adults with TB that is resistant to both INH and rifampin.
Commonly Associated Conditions
- HIV infection
- Chronic renal failure
- Immunosuppression, including chronic daily steroid use, high-dose steroid use or tumor necrosis factor-α (TNF-α) agonists, cancer chemotherapy
- Social issues: incarcerated adolescents, infants, and children in homeless shelters
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