Bacterial Infections in Childhood: TB

Description

Tuberculosis , also commonly called TB, is a contagious bacterial infection that usually affects the lungs, but can also spread to other body organs. TB is caused by bacteria that are members of the Mycobacterium group, most often by Mycobacterium tuberculosis . It usually passes from person to person through watery airborne droplets of coughs, and in the mucus that infected persons cough up from their throats. About one third of the world's people (including 10 to 20 million in the US) have been infected with TB. The incidence of childhood TB increased by 40% in a 6 year period (1987 to 1993) in the US as a result of poverty, immigration and HIV infection.

Symptoms and Signs

A TB infection may not cause any symptoms of disease. This is because the body's natural immune defences can "wall-off" the TB bacteria and prevent them from spreading, however, the walled-off bacteria often remain alive, sometimes for decades and can be 'reactivated' by anything that weakens the immune system (e.g. malnutrition or a severe illness), causing illness.
TB can affect fairly large areas of a child's lungs without causing any noticeable symptoms. Of all age groups, infants are most likely to have signs of illness, including dry cough, trouble breathing, fever, poor appetite, night sweats and trouble gaining weight. Older children may wheeze, breathe faster than normal, lose weight, feel unusually tired or complain of feeling short of breath.

Diagnosis and Treatment

Often a child's TB infection is first discovered by a tuberculin skin test , which is usually given three times during childhood (12 months, between 4 and 6, and again between 14 and 16). The test is positive if the area around the injection site becomes red, hard or raised (like a small bump) within 2 days of the injection. Chest x-rays are then the next step to confirm any suspicion of TB.
Anti-tuberculosis medicines (such as isoniazid or rifampin), which are taken for a long period of time, are the main treatment option. If TB is diagnosed, the immediate family members should also be checked without delay for signs of the disease. [ 1 ]

Tuberculosis in Newborns

A foetus may acquire tuberculosis from the mother before birth, before or during birth by breathing in or swallowing infected amniotic fluid , or after birth by breathing in air containing infected droplets. About half of the infants born to mothers with active tuberculosis develop the disease during the first year of life if they aren't treated with antibiotics or vaccinated.

Symptoms and Signs

The symptoms of tuberculosis in a newborn can include fever, drowsiness, poor feeding, fail to thrive and difficulty in breathing. Many other symptoms are possible, depending on the extent of the infection. The liver and spleen may be enlarged, due to their filtering of the tuberculosis bacteria, causing activation of infection-fighting white blood cells there.

Diagnosis and Treatment

If a pregnant woman has symptoms of tuberculosis, she is given antibiotics, and the mother-to-be who tests positive for TB but shows no symptoms, may also be prescribed an antibiotic. However, treatment with certain antibiotics are usually delayed until the last 3 months of pregnancy or until after delivery, because the risk of liver damage in the woman is higher during pregnancy. If a resistant strain of tuberculosis is suspected, additional drugs may be given. These don't seem to harm the foetus.
An infected mother is kept isolated from her baby until she is no longer contagious and the infant receives antibiotics as a preventive measure. If the brain is involved, corticosteroids may be given at the same time. The baby may also be vaccinated with BCG vaccine . Vaccination doesn't necessarily prevent tuberculosis but usually reduces its severity. [ 2 ]

Sources

1. This information is presented in summarised form and has been taken from Intelihealth.com, Children's Health Section: http://www.intelihealth.com/
2. From The Merck Manual of Medical Information – Home Edition , edited by Mark H. Beers and Robert Berkow. Copyright 1997 by Merck & Co., Inc., Whitehouse Station, NJ: http://www.merck.com/mmhe/index.html