Fulcrum of TB diagnosis in children
By Owen Nyaka:
Abandoned by her husband of three years, who decided to marry another woman, Alinafe Chirwa of Group Village Headman Bitchayi, Traditional Authority Maganga in Salima District is struggling with life threatening and highly contagious Multi Drug Resistant Tuberculosis (MDR – TB) disease.
Diagnosed on April 23, 2018, she has two under five children (paediatrics) whose future is at stake. She has an aunt who brews African beer – Kachasu but still her aunt, who is an ex-TB patient, is far from being called reliable to care for neither her niece nor her niece’s children.
Periodically, the little children go without nutritional food. They are also exposed to open fire smoke when brewing the local beer. Sometimes it gets overcrowded when other heavily intoxicated Kachasu customers are accommodated in their vicinity.
Although the children are believed to have contracted the disease from their adult contact, Alinafe’s little ones appear to be invisible towards the fight in ending TB.
Sputum
Alinafe’s children, just like most paediatrics in Malawi and across Africa, face a number of challenges that continue to bedevil the diagnosis of TB in children. The most common form is pulmonary TB with respiratory symptoms and diagnosis is largely confirmed by examining sputum and chest radiography. Children, especially the young ones find it difficult to cough and produce sputum for examination.
Traditional microscopy or more advanced fluorescent microscopy requires a good sputum sample the appropriate lab test to be done. Although more sensitive tests are expensive, they are now becoming more accessible even in some remote settings through laboratory networking where samples are collected from clients and sent to established referral labs with the requisite equipment and technical staff.
However, chest radiography (x-rays) is also expensive and not available especially in rural health facilities like Maganga where Alinafe’s children are present. Extra-pulmonary TB which is TB in parts of the body other than the lungs often requires higher clinical skills and laboratory tests to confirm it. HIV infected children may also test negative on sputum microscopy. Basically, if TB diagnosis is missed, the children cannot be treated appropriately.
TB diagnosis in children
Malawi College of Medicine Assistant Lecturer on TB diagnosis in children, Doctor Dominic Moyo says paediatric TB is common but difficult to diagnose. Clinical diagnosis remains the bedrock of TB diagnosis in children. Sputum is difficult to obtain in children; however where possible techniques are available to induce sputum for microscopy and culture but also recently the introduction of GeneXpert has improved TB diagnosis in children.
He said TB diagnosis is usually made on epidemiological features and clinical features at presentation – epidemiological features look at those areas where TB is widespread and clinical features basically looks at the symptoms at presentation and also what is found on examination which in most cases depends on the affected system of the body.
Other samples which can be collected depend on presentation of the TB gastric aspirates and other body fluids like cerebral spinal fluid where TB meningitis is being suspected.
Moyo, who is currently in Capetown, South Africa finishing his specialist training in general terms, said TB is usually suspected in children who are HIV exposed, born to mothers who are reactive, have HIV infection or diseases, have non-specific symptoms of not gaining weight despite feeding, sometimes they may have poor feeding, prolonged fever, previously treated for a respiratory tract infection but not responding to treatment.
He says they rely more on clinical presentation of the child but the challenge comes when they are looking for ancillary test to confirm the diagnosis.
‘In our setting we do chest x-rays which may or may not show characteristic features known to be associated with TB. There is also a non-specific test called a mantoux test which is done by introducing purified protein derivative of the bacteria that cause TB into the layer of skin and measure the reaction.
“Sometimes we can induce sputum in the children or do what we call gastric washing where we starve the child for at least 12 hours and then early in the morning we put a tube which goes inside the stomach of the child, and then we introduce some fluid inside and then aspirate it back. These tests however are not as good as you would get with sputum testing which is an ideal thing to do,” Moyo says.
Moyo says mantoux testing, also known as Tuberculin Skin Test (TST) as of recent past, is no longer routinely done in public facilities. TST which does not require specific equipment at all but is just an injection, is widely used but suffers poor specificity in those receiving the bacilli Calmette-Guerin vaccine and poor sensitivity in individuals with HIV infections.
Treatment
Drugs used in paediatrics are the same as those that are used in adults and the duration depends on the type and severity of TB; 12 months for TB meningitis, TB in the bones and spine while the rest are for six months.
The Pediatric expert says treatment is divided into two phases: Intensive phase consisting of 4 drugs followed by a 2 drug continuation phase for a period of 10 months if severe as mentioned above and 4 months for the rest.
Drug formulation: pill burden is less becoming an issue because of fixed dose combinations, meaning all the drug involved in treatment are made as one tablet composed of different strengths of each constituent drug, however where the child is HIV positive and on ART the issue of pill burden can arise.
“In paediatrics we prefer the use of syrups where possible as these are well tolerated with children but currently as far as I know we do not have TB drugs in syrup form in our setting’” Moyo says.
Prevention
He is of the view that vaccine is the key. He said the others include targeting at risk populations such as children who are infected with HIV or exposed need proper follow up and management, poverty alleviation, reduction of overcrowding, reduction of smoke exposure and indoor air pollution like cooking on open fire.
The availability of TB prophylaxis to certain populations; Moyo said, for example, a child born to a mother with TB diagnosed in the third trimester will qualify for prophylaxis given that the child has been proven not to have the disease already.
He said this prophylaxis is for the duration of six months, also children fewer than five with household contact with TB is eligible for prophylaxis provided the disease has been excluded in the child.
As Alinafe continues battling with MDR TB, contact tracing is imperative because it has been proven that children across the globe are believed to contract the disease from their adult.
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