CNS: Solving the puzzle: Diagnosing tuberculosis in children

Dr Muherman Harun (Indonesia) raises key challenges related to diagnosing TB in children

The Citizen News Service (CNS) is conducting an online consultation on childhood tuberculosis (TB) in lead up to the 2012 World TB Day. I will like to share our views on the ‘essentials’ of the diagnosis of TB in Children. The main means of diagnosing TB in children is undoubtedly, chest X-ray.

1. Children sometimes may have adulthood TB (post primary TB). Diagnosis is relatively simple. Symptoms are like in adulthood TB: few weeks cough, sub-febrile, night sweat, chest pain and sometimes hemoptoe. Every doctor treating TB can easily recognize TB features on chest X-ray: infiltrates or patches usually in upper lung fields, sometimes with cavitation. If cavitation is present, sputum should easily reveal Acid fast bacilli (AFB). This child can expectorate! Treatment will instantly stop infection and cure the disease. Without treatment, the child will die within one or two years.

2. Child may have miliary TB. After witnessing the miliary shadows in the lung(s) on chest X-ray, even once only, the doctor will remember this X-ray’s characteristic feature. Symptoms: weight loss, loss of energy and activity, fever, cough. Without treatment the child may die. Fortunately, this is a rare development after BCG.

3. Child may have meningitis TB. Symptoms include, longstanding headache, febrile and drowsiness. Very characteristic/diagnostic signs are neck or back stiffness. Without treatment the child may die or suffer from sequellae, like hydrocephalus, blindness, deafness or other neurological defects. This is also fortunately, a rare development after BCG. Chest X ray may be normal, or miliary TB may be present.

4. Child may have primary TB. Chest X-ray may show enlarged hilar lymph glands. The primary TB shows no symptoms. Unfortunately, increased bronchovascular markings are often overdiagnosed as enlarged hilar lymph glands. Despite outrageous misjudgment of a number of primary TB cases by our colleagues, we should also realize that there are how many millions of primary cases that go unnoticed and get spontaneously cured …..

If occasionally, primary TB is developing progressively, then the disease may develop into miliary TB or meningitis TB. Fortunately, such developments become rare after successful BCG vaccination.

In some cases, if body resistance is low, the primary disease will develop into post primary TB. This condition however, can not be prevented by BCG. But in this case the diagnosis should be relatively simple. After treatment, sputum AFB becomes negative and the disease causes no further infection.

Who are the main killers of children with TB?

The main killers are: miliary TB and/or meningitis TB. They are the rapid awesome killers. Unabated, they may kill within several weeks. Fortunately, BCG gives effective protection.

The other is the mass killer: post primary TB, killing the children slow but sure. Without treatment the child may die within a year or two. These killings are not prevented by BCG.

Important diagnostic factors

• Sputum examination of AFB is most successful if lung/bronchial tissue is affected or damaged as in post primary TB. However, in miliary and meningitis TB, the bacilli are spread through the bloodstream i.e. hematogenic spread, hence bacilli are usually not detectable in sputum. In primary TB, bacilli are spread through the lymphatic system (hilar lymph glands) and bloodstream. Therefore, AFB are usually absent in the sputum. This explains the difficulty to detect AFB in sputum. We never carried out the gastric lavage for AFB. Such procedure is too drastic and traumatic for too little yield or impact, if any.

• The tuberculin test in under-fives is particularly useful in the diagnosis of TB (if BCG was not given) However, the higher the age of the patient, the lesser diagnostic value the tuberculin test will have. About the usefulness of the tuberculin test after BCG, there’s an old saying which still stands true: “After BCG, the tuberculin reaction goes, as the wind blows!”, in other words, the tuberculin test is no more a reliable diagnostic tool after BCG vaccination. There is up till now, no serological or PCR tests for the diagnosis of TB.

• The presence of a house-hold contact who is expectorating TB bacilli, is an important factor, supporting the diagnosis of TB in children.

• Lymphatic glands caused by TB can usually be seen in the neck. These enlarged glands may not be painful, and are presented in clusters. If there is discoloration (livid) and fluctuation or abscesses appear, TB diagnosis becomes clear and treatment can be given right away. The presence of TB glands in the neck becomes very helpful in the diagnosis of pulmonary TB. After only a few weeks of anti-TB treatment, the swollen lymph glands will soon reduce in size. This also supports the diagnosis of TB of the lung.

(But there also are lymph glands in the neck of viral origin. If thoroughly examined, there will be so many small children with enlarged lymph glands in the neck, which are not TB. These glands are usually not directly visible and will come and go with the (febrile) condition of the child. This condition does not need further examination nor treatment. As the child becomes older, the enlarged glands will disappear spontaneously).

Finally, “How to get to zero new TB infections in children by 2015?” I’d like to answer this STOP-TB question by emphasizing and reiterating the main and grand principle: “Focus on the main reservoir, sources of TB bacilli. They are the ones that cough, spreading the AFB into the air”. Find, treat and cure them, no more and no less. Contact (centrifugal or centripetal) examination could be carried out on a limited and selective scale.

The important risk factors i.e. “malnutrition, poverty, environmental pollution, poor housing, overcrowding, indoor air pollution, passive smoking, etc” may not have an important role to play in an effective TB control program. This was spectacularly shown from the historic WHO/BMRC/MRCI experiment of Madras in the fifties.

If we only can persistently treat and diligently cure all of our TB patients who are infectious, eventually, there will be no more children getting infected! Hence, chase without delay retrieve any absconders who and wherever they are, at any cost! Provide patients the fullest treatment with the very best regimen available, so that the disease be completely cured and forever.