During residency, I have encountered three different presentations of tuberculosis (TB): a 4-monthold Dominican infant with neurologically devastating TB meningitis; a 17-year-old immigrant from Mexico who died of massive hemoptysis and acute respiratory distress syndrome secondary to TB; and a 5 year old from Africa with recurrent pancreatitis secondary to miliary TB. TB remains one of the most important infectious diseases in the world in terms of morbidity and mortality. Because residents often serve people from all over the world, they need to be aware of the protean manifestations of this disease and of who is most at risk.
Adult TB has a bimodal distribution. Non-Hispanic whites tend to have reactivation disease in old age, whereas minority populations have primary disease with a peak incidence between 20 and 45 years of age. This is important to pediatricians because it corresponds to peak childbearing age. Most TB in children occurs among minorities, particularly those who live in large inner cities. This means that pediatrie residents often see these patients in clinic or on the wards. On the wards, they often are admitted with the diagnosis of or signs or symptoms suggesting TB. It is in clinic where residents must be on guard and where asking the right questions with the right follow-up can be most helpful and rewarding.
The highest rates of TB occur among children younger than 5 years.1 In a household with an adult with TB, infants and toddlers frequently are infected. Residents must be aware of the family history. In high-risk populations, they need to monitor the parents' health history. They must be even more vigilant if a parent is in a high-risk category. Recent immigrants from countries with a high prevalence of TB, incarcerated adults, adults with human immunodeficiency virus (HIV), illicit drug users, prisoners or prison workers, shelter residents, migrant farm workers, the homeless, and even health care workers exposed to high-risk patients are at high risk.
There are three major stages of TB: exposure, infection, and disease. Exposure means that a person has had contact with someone with infectious TB. The exposed person must have a physical examination and a tuberculin skin test (TST). If the results of the TST are positive, a chest x-ray is necessary. A child younger than 5 years with significant exposure to TB must begin window prophylaxis immediately. In young children, severe TB can develop in less than 3 months. Such children must be treated for 3 months after contact with the source case has been broken. If the results of a repeat TST are negative, treatment can be safely stopped.
Infection means that a person has inhaled Mycobacterium tuberculosis and has a positive result on a TST. A chest radiograph should show normal findings. Children with latent TB infection (World Health Organization [WHO] class II) should be treated for 9 months, usually with isoniazid.
Disease means that there are signs and symptoms of TB, that the findings on chest radiograph are abnormal with more than hilar adenopathy, or both. Up to 43% of infants, 24% of 1 to 5 year olds, and 5% to 15% of adolescents have disease after untreated infection.1 Treatment of disease (WHO class III) generally is a 6-month course of isoniazid and rifampin, supplemented by pyrazinamide during the first 2 months. In areas with multiple-drug resistance, ethambutol is added for the first 2 months. TB meningitis requires 12 months of treatment.
The signs and symptoms can be subtle. Children may be asymptomatic or have a lowgrade fever, weight loss, or cough. The pulmonary disease is often silent. The guest editor of this issue, Dr. Bye, encountered his first TST during internship at the Buffalo Children's Hospital. An adolescent girl was admitted to the hospital with abdominal pain but no respiratory symptoms. It was only after she underwent appendectomy and the pathologist made the diagnosis of TB that her chest radiograph was found to have positive results. If that could happen in Buffalo in 1976-1977, imagine how easily it could happen in an inner city today. We need to be vigilant not only for our patients, but also for ourselves.
Extrathoracic disease is more common in children. Scrofula (also known as tuberculous cervical adenitis) is the most common extrapulmonary manifestation in children. Miliary TB is more likely in younger children. When Dr. Bye was at St. Christopher's Hospital for Children in Philadelphia, an infant in septic shock was brought to the emergency department. A chest radiograph during resuscitation revealed miliary disease, and the autopsy confirmed TB. Obviously, vigilance is the key.
The most serious complication is TB meningitis. Children younger man 2 years with infection have a 5% to 10% risk of meningitis, which generally occurs soon after the primary infection. Initial symptoms of meningitis may be nonspecific and diagnosis can be difficult because the results of the chest x-ray and TST may be negative. We must have a high index of suspicion for meningitis and a low threshold for performing lumbar puncture.
The diagnosis of TB is most often made in children by a positive result on a TST, x-ray findings consistent with TB, or close exposure to a known case. The definitive test for diagnosing TB is the mycobacterial culture, which is notoriously difficult to obtain from a child. Expectorated sputum almost never exists. Gastric aspirates must be done properly for a decent yield. This means that the nasogastric tube has to be the child's "wake up call," and the lavage must be done with sterile water. A properly done gastric aspirate is at least as rewarding as, and in some hands more rewarding than, a bronchoalveolar lavage. However, if die adult source is known, together with the sensitivity of that person's organism, the child may not need a culture. If the contact source is not known, the child is very ill, or there is drug resistance in the community, a culture should be attempted.
The American Academy of Pediatrics recommends a TST only for children who are at increased risk of TB.2 Risk factors include an infected individual in the home; recent immigration to this country from an endemic area; travel to an endemic area; signs and symptoms of the disease; HIV infection; and exposure to adults at high risk for TB (eg, HIV infection, incarceration, drug abuse, or homelessness). Children in high-prevalence areas should be screened by history and physical examination at each health care visit, and those with any of the above risk factors should be tested.
Targeted screening and testing of children at high risk for M. tuberculosis infection should be standard in our care of children. Children with TB represent a failure of the health care delivery system to adequately control the spread of the disease. By identifying infected children and using appropriate treatment, we can help to prevent morbidity and mortality in our patients and control the spread of this disease.
1. Correa AG. Unique aspects of tuberculosis in the pediatrie population. Clin Chest Med. 1997;18:89-98.
2. American Academy of Pediatrics. 2000 Red Book: Report of the Committee on Infectious Diseases. Elk Grove Village, IL: American Academy of Pediatrics; 2000:593-613.