How Common are Latent and Active Tuberculosis Cases Identified Among Contacts?

Patient Presentation
A 4-year-old female came to clinic for her health supervision visit. The mother had no concerns about the child but wanted to know if there was anything else she needed to do for the child as she was finishing her own treatment for tuberculosis.
The mother was a legal immigrant in the United States from South East Asia, who had visited her relatives and returned to the United States. After the visit she found out she was pregnant and as part of her routine obstetrical care and history, she had a Mantoux skin test placed that was positive.
She had no symptoms of active disease and a normal chest radiograph. At 16 weeks gestation she was placed on isoniazid and pyridoxine for 9 months. The public health department had investigated for potential contacts in the United States and all were negative on physical examination and for skin testing.
The relatives were also contacted by the mother. The mother’s cousin began receiving some treatment but the mother was unsure about what it was.
The pertinent physical exam showed a happy, smiling infant with normal development and growth parameters.
The diagnosis of a healthy infant with a mother who was finishing treatment for latent tuberculosis infection was made. The mother was counseled that there was no other treatment or other evaluations that needed to be made for the child. Follow-up with her own health care provider was encouraged. The mother was also encouraged to contact the public health department about potential visits to her home country or visits from relatives to the United States.

In children and adolescents, most tuberculosis infections caused by Mycobacterium tuberculosis or Mycobacterium bovis are asymptomatic.


  • Tuberculin skin test (TST) – a positive TST indicates possible infection with Mycobacterium tuberculosis or Mycobacterium bovis. Reactivity usually occurs 2-12 weeks after initial infection with a median interval of 3-4 weeks.
    In general, TST should be interpreted the same whether a child has received BCG vaccine or not. Specific recommendations for interpretation of TST can be found in the AAP’s Red Book. (see To Learn More below).
    The Mantoux skin testing method of intradermally injecting 5 tuberculin units or purified protein derivative into the volar aspect of the forearm is recommended. Multiple puncture tests are not recommended because of poor sensitivity and specificity.

  • Exposed person – a person with recent contact to another person with suspected or confirmed contagious pulmonary tuberculosis, who has a negative TST, normal physical examination, and chest radiograph.
  • Latent tuberculosis infection – a person with a positive TST with normal physical examination and chest radiograph.
  • Tuberculosis or active disease – a person with symptomatic disease which may be pulmonary, extrapulmonary or both.

Children, especially those < 5 years, have a high likelihood of progression from latent to active disease. They are also more likely to develop disseminated and serious forms of tuberculosis.
Increased risk of dissemination also occurs in children with impaired immune systems especially HIV infected children, and those with chronic disease such as diabetes, renal failure, malnutrition and recent measles.

Clinically, patients with active disease can present with fever, weight loss, poor weight gain, growth delay, cough, night sweats and chills.
Pulmonary tuberculosis from Mycobacterium tuberculosis will show radiographic findings that range from normal to abnormal radiographs showing lymphadenopathy, atelectasis, segmental or lobar infiltration, pleural effusion, and cavitary or miliary lesions.
Extrapulmonary symptoms from Mycobacterium tuberculosis include meningitis, granulomas of lymph nodes, bones, joints, skin, the middle ear and mastoid. Renal tuberculosis also occurs.
Another manifestations from Mycobacterium bovis is intermittent partial intestinal obstruction with chronic abdominal pain.

Treatment for active disease depends on a number of factors including the actual active disease manifestations, organism isolation and sensitivities to anti-infective agents, and previous treatment with anti-infective agents. Drugs used must be used in combination to decrease drug resistance. Drugs commonly recommended include isoniazid, rifampin, pyrazinamide, ethambutol and streptomycin.
Treatment for latent tuberculosis infection is isoniazid for adults. Infants, children and adolescents with latent tuberculosis who have never received anti-tuberculosis therapy should receive isoniazid therapy, unless the known source has isoniazid-resistant tuberculosis or another specific contraindication exists.
Specific recommendations for treatment can be found in the AAP’s Red Book. (see To Learn More below). Women who are pregnant with latent infection should receive isoniazid and pyridoxine for 9 months beginning after the first trimester.

Learning Point
In low incidence countries such as the United States, for 1 active tuberculosis case, 5-10 contacts are identified. Among these contacts 30% are found to have latent tuberculosis infections and another 1-4% are found to have an active tuberculosis infection.
In high prevlance countries among the contacts 50% are found to have latent tuberculosis infections and another 10-20% are found to have active tuberculosis infection.

Questions for Further Discussion
1. Where are the high-prevelance regions of tuberculosis in the world?
2. What are the recommendations for isolation of potential source patients?
3. What are some of the manifestations of non-tuberculosis Mycobacterium?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Information prescriptions for patients can be found at MedlinePlus for this topic: Tuberculosis
and at Pediatric Common Questions, Quick Answers for this topic: Tuberculosis

To view current news articles on this topic check Google News.

American Academy of Pediatrics. Tuberculosis In Pickering LD, Baker CJ, Long SS, McMillan JA, eds. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th edit. Elk Grove Village, IL: American Academy of Pediatrics; 2006;678-698.

Hopewell PC, Pai M, Maher D, Uplekar M, Raviglione MC. International Standards for Tuberculosis Care. Lancet Infect Dis. 2006;6:710-25.

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    8. Health care services aimed at preventing health problems or maintaining health are provided.
    9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

  • Systems Based Practice
    25. Quality patient care and assisting patients in dealing with system complexities is advocated.
    26. Partnering with health care managers and health care providers to assess, coordinate, and improve health care and how these activities can affect system performance are known.

    Donna M. D’Alessandro, MD
    Associate Professor of Pediatrics, Children’s Hospital of Iowa

    November 27, 2006