Pediatric Tuberculosis Risk Factors and Test for Detection

Standing as Nation Against TB! Despite these challenges, it is clear that improvements in diagnostics are driving a feedback loop in Indian health care. The promise of improved tests drives their uptake, their uptake results in better health outcomes, improved outcomes attract more funding for health care systems and better- funded systems are an incentive to the development of even better technologies. We are particularly optimistic about the potential role of our government in the execution of the strategy and implementation. We now have the capacity to develop low-cost generic or novel assays adapted to local framework and incorporate that scale-up in both, National Tuberculosis-Control Programs and private laboratories, supported by a successful public-private partnership. It would not be wrong if we say, that if we tackle our own TB problems successfully, the elimination of TB by 2025 might become a reality!

How often does our mind trail to the thoughts of an otherwise squealing baby now muffling uncomfortably might be a sign of an imminent malady?

We usually have the tendency to neglect certain undoubted incidences and then bewail later when adversity finally strikes. A very evident alteration in behavior and appearance is the first sign to raise your guards. Reduced playfullness, apparent weight loss, persistent fever , and breathlessness are the prominent prodromes of thriving illness. Children are more prone to getting infections because they yet have not developed their protective immunities. Also, toddlers are exposed to the risk as they are always surrounded by people and in contact with many other children, thus transmission of infection becomes easy. One such threat which is arising predominantly among the young is Tuberculosis-termed as 'Pediatric TB'.

TB is an airbome infection caused by inhalation of droplet nuclei contaminated with an acid-fast bacilli, Mycobacterium tuberculosis of the M. tuberculosis complex group, which are disease-causing pathogen.

What causes TB in infants?
TB in infants is a matter of concern because it often goes unnoticed or is overlooked due to csymptoms and difficulty in diagnosis. This is the cause of inefficiency in estimating the actua expanse of pediatric TB leading to mortality in children, even though TB is a preventable and curable, disease . Because most of the cases so unrecognized and left untreated, pediatric TB has been termed as "hidden epidemic". World Health Organization (WHO) has estimated a prevalence of about 10 lakh, children being infected with TB each year.

Adults are The Primary Source of infection for Pediatric TB Young children are prone to infection because their immune system is not as strong and developed as the adults. When such infants and children are exposed to adults with active-TB, they contract the TB bacilli. Pediatric TB is usually considered as primary intection because once they are exposed to the bacilli they have higher risk of developing active TB than adults. They also have high possibilities of developing extrapulmonary forms of TB i.e. miliary TB and TB meningitis. If a child is diagnosed with active tuberculosis it is advised to investigate the family to analyze the source of the infection.

What are the major risk factors of tuberculosis in Children?
Children are at a higher risk of acquiring TB infection and developing into active TB. Other risk factors include contact with infected adults with active-TB or with latent stage TB infected adult, HIV patients with weakened immunity and poor hygienic conditions.

The children who are more prone to these risks are- infants below 3 years of age, and adolescents before or during puberty.

What is the first major symptom of tuberculosis?
The initial signs that set the alarm on, includes: fever , anorexia, malaise (irritability, restlessness), night sweats, mild dyspnea (shortness of breath), swollen glands, and persistent cough.

Usually the characteristics of TB in young children varies depending upon the site of infection involved i.e. pulmonary or extrapulmonary tuberculosis (EPTB).

What is Pulmonary TB?
It is a condition where the child's lungs are infected. The manifestations are shown according to the specificity:
Endobronchial TB- It is an infection of the tracheobronchial tree of the airways from larynx to the lungs. Signs and symptoms include enlargement of lymph nodes resulting in bronchial obstruction (air-way blockage), esophageal compression (narrowing of normal opening of swallowing tube), vocal cord paralysis, hemidiaphragmatic paralysis (paralysis of one side of diaphragm).

Progressive Primary Pulmonary TB- It is an infection of the functional parts of the pulmonary system and signs and symptoms include, enlargement of caseous area resulting in pneumonia, atelectasis and air-trapping. The child suffers from persistent coughing that may last for more than 2-3 weeks along with chest pain and may also cough out blood due to infection causing damage in pulmonary artery

Extra-Pulmonary TB It is an infection outside the lungs. It is reported that one third of all TB cases show EPTB. Children appear to have a higher tendency of developing it.
The manifestations are shown according to the specificity: Lymphadenopathy. It involves the anterior or posterior cervical and supraclavicular nodes. Signs and symptoms include having history of enlarged nodes. Infected lymph nodes are firm and non- tender with no signs of inflammation.
What is TB Meningitis?
It is one of the most severe complication of TB. It develops majorly in children younger than 2 years. Moderately acute signs and symptoms occur after 3-6 months of initial infection which includes anorexia, weight loss, fever, vomiting, seizures and alteration in sensory apparatus. Extreme conditions (final stage) may cause major neurologic defects including coma and abnormal movements (e.g. paralysis, paresis).

Why is Diagnosis in young children extremely difficult?
Diagnosis in young children is extremely difficult for two reasons:
1. They cannot cough up enough sputum for laboratory tests (e.g. Sputum smear microscopy).
2. Most children with active pulmonary TB will have paucibacillary disease (with few bacillus) and they show no or rare symptoms of infection. It becomes challenging to perform definitive diagnosis but it is very crucial to prevent the infection from progressing to life threatening disease. It is estimated by WHO that out of 13 lakh pediatric TB cases only 13% turn out to be eligible for preventive measures. This statistics showcases the seriousness of early diagnosis because earlier the infection is detected, more cautious and safe the patient will get to be.

Most common method used for obtaining the organism from children is Gastric lavage. As children tend to swallow their secretions, the organisms can be procured from their stomach. The Nasogastric (NG) tube is passed through the stomach and lavaged. The gastric contents are removed containing the organism and sent for Pathology Test.

What are the Tests for detection of TB?
1. Radiology. This method is not specifically diagnostic but radiological finding is important for TB meningitis. Lymphadenopathy, hilar and paratracheal adenopathy are the most common abnormalities identified by chest radiography.
2. Immunology. This section involves tests which can not differentiate between latent and active TB.
a. Tuberculin Skin Test (also known as Mantoux test)-Detects the presence of tuberculosis infection by studying the reaction of patient's body on injecting small amount of tuberculin protein (purified protein derivative; PPD).
b. Interferon Gamma Release Assay (IGRA)- It is the in vitro detection of immune response against M. tuberculosis antigens
3. TB Culture and Drug Susceptibility Test- Culturing of the Mycobacterium proves to be more sensitive than smear microscopy, and it can also allow subsequent characterization of the strain and Drug Susceptibility Testing (DST), Mycobacterial Growth Indicator Tube (MGIT), can be used for culturing, but growth can be evident within 3-6 weeks, which delays in obtaining the results. Microscopic Observation Drug Susceptibility (MODS) is another technique of DST.
4. TB-PCR- It is DNA based test which detects specific DNA of MTB, this technique has greater sensitivity than conventional diagnostic techniques. Along with sputum, it can be used for EPTB samples also, such as gastric aspirate, pleural fluid and cerebrospinal fluid.
5.CBNAAT (GeneXpert MTB/RIF)- MTB/RIF is an automated, TB specific CBNAAT that uses real time PCR for the rapid detection of TB, as well as for detection of rifampicin resistance, which counts as a surrogate marker for MDRTB. The sample preparation, amplification and detection are done by automation and the results can therefore be achieved in as few as 100 minutes. It aids in diagnosing pulmonary TB and EPTB in adults as well as in children.
6. MDR/XDR Line Probe Assay.Line probe assay technology detects the genetic mutations associated with resistance to (first line; MDR) rifampicin, isoniazid and (second line; XDR) fluoroquinolone, aminoglycosides, cyclic peptides.

The Course of Managing and Treating
The treatment for pediatric tuberculosis is basically same as that for adults. Children are first prompted to intensive phase of treatment following a continuation phase. The first intensive phase is crucially induced to eradicate maximum tuberculosis bacteria from child's system followed by the second continuation phase that helps to slowly banish the remaining passive bacteria

What drugs are used primarily to treat tuberculosis?
The first and second line drugs like rifampicin, moxifloxacin, rifabutin, linezoid, etc., are given daily for initial intensive phase. The next continuation phase starts only after the chest radiography and sputum test results are out and the medications are extended for a duration of 5-7 months.

The relationship between the children and every other family member is based on pillars of care and love and our support is the best we can give in such critical times of our lives. At our extent, awareness and knowledge is the crucial factor for precautionary measures. TB is a curable disease and its early diagnosis is the path to well-being!