Tuberculosis

Tuberculosis

Tuberculosis (TB) is a contagious infection, usually attacking the lungs although it can spread to other body organs (Miliary TB) and  is caused by mycobacteria (usually Mycobacterium tuberculosis).  Like many other illnesses it is passed from person to person through airborne droplets from coughs, but also in the mucus that the affected person may cough up (this may be bloodstained).  Children usually catch TB from another household member.  Less often outbreaks can occur in school or nursery.

Tuberculosis is common and a third of the world’s population suffer from it.  It has increased significantly in developing countries over the last eight years.  Someone with TB may not have any symptoms because the body’s immune defences can wall-off the bacteria.  However the bacteria are not completely killed and if anything happens to lower the body’s immune defences such as malnutrition, a severe illness, or a course of oral steroids, then infection can reactivate and TB infection can spread through the body.  The lungs are usually affected but in the later stages, bacteria can spread through the blood to the lymph nodes, brain and joints.

What to look for

Although extensive lung infection in TB can occur without any symptoms, of all the age groups, infants are most likely to show signs of illness with difficulty breathing, dry cough, fever, poor appetite and night sweats.  There may also be failure to thrive.  Older children may wheeze, have an abnormally fast breathing rate, lose weight or feel tired or short of breath.  

A child’s TB infection may be first discovered by a skin test (tuberculin, Mantoux, Heaf).  Countries such as America where BCG (immunisation against TB) is not performed, then the tuberculin test is done at a month, at 5 and at 14 years of age.  If at any time this test is positive, then the child should be assumed to have come in contact with TB and a six month course of anti-tuberculosis therapy should be given.

In countries where the BCG is given routinely, then this should produce a positive skin test (this will usually be 2-4mms).  If the skin test is strongly positive causing an area of induration and redness greater than 1cm, then BCG vaccinated children should be considered to have been infected and should receive a course of treatment.  At the same time as the course is given, a chest-x ray will be taken to look for evidence of TB. Other family members will also be tested and if found to be positive, will need to be treated with anti-tuberculosis medicine.

Call your doctor if

Any family member has been found to have a positive anti-tuberculin test or diagnosed as having TB.  Likewise if your child has wheezing, fever, night sweats, poor appetite or shortness of breath or has, for a long time, felt weak or tired.  Likewise if your child is failing to put on weight, this should be another reason to get your child checked over.

Immunisation

Under the age of 3 months the BCG – intradernal injection of live attenuated TB bacteria can be given without skin testing - after 3 months need to do a Mantoux skin test and return after 48 hours.