Communicable Diseases Module: 16. Tuberculosis Treatment in Special Conditions: TB in Children, HIV/TB and Drug Resistant TB

Study Session 16  Tuberculosis Treatment in Special Conditions: TB in Children, HIV/TB and Drug Resistant TB

Introduction

In this study session, you will first learn about diagnosis and management of tuberculosis in children and how this differs from the adult (Section 16.1). Section 16.2 discusses what happens with patients who are infected with both TB and HIV — an example of a co-infection — and how this is managed. Finally, in Section 16.3 we look at the situation where patients have TB that is resistant to drugs.

Of all TB cases registered with the National Tuberculosis programme in Ethiopia, up to a fifth occur in children. Children can present with TB at any age, but the most common age is between one and four years. In most cases, TB in children is a result of primary TB (i.e. the first infection) from an infectious adult or older child, unlike cases in adults which are most often due to reactivation of a previous TB infection. The best way to prevent childhood TB is therefore by proper identification of those who may be infected with TB, and treatment of active TB patients in the home and community.

The HIV epidemic has made the position with regard to TB worse by increasing the risk of reactivation of latent TB infection and by facilitating more rapid progression of TB disease. TB can readily be transmitted to both HIV-negative and HIV-positive households and to other close contacts of infectious patients.

Learning Outcomes for Study Session 16

When you have studied this session, you should be able to:

16.1  Define and use correctly all of the key words printed in bold. (SAQ 16.3)

16.2  Describe the key differences in the diagnosis and management of TB in children and adults. (SAQ 16.1)

16.3  Identify the key factors that will help you look after patients with HIV/TB co-infection. (SAQ 16.2)

16.4  Describe the main causes and consequences of drug-resistant tuberculosis. (SAQ 16.3)

16.1  Diagnosis and management of TB in children

In this section, you will learn how to diagnose and treat TB in children and how to follow their progress after treatment. The diagnosis is made at the health centre or hospital and children will be referred to you to continue treatment in the community under your supervision. The families of children who have TB may ask you questions regarding the drugs that their child is required to take, so it is very important to know a little about the major anti-TB drugs, even though you are not the key person involved in diagnosing TB and prescribing anti-TB drugs.

Very often children who are exposed to a positive contact within their close environment (especially the household), will acquire tuberculosis infection. A close contact is defined as someone living in the same household, or being in frequent contact with a person who is sputum smear-positive for TB. This exposure leads to the development of a primary (the first or original) lesion in the lungs, which is likely to spread to the regional lymph node(s). In the majority of cases, the child’s immunity will control the disease process at this stage. Progression to TB disease occurs more commonly in children under five years of age and in children who are HIV infected (because their immune systems are therefore compromised), or who have had measles, or who are malnourished.

16.1.1  Symptoms of childhood TB

Children with TB develop chronic symptoms in most cases, and TB may be a more acute disease in the presence of HIV infection. The commonest symptoms that parents notice are:

• Chronic cough: persistent cough (present for more than two weeks) and not improving.
• Fever: fever of greater than 38^°C for 14 days, after common causes such as malaria and pneumonia have been ruled out.
• Weight loss: documented weight loss or failure to gain weight.

Figure 16.1  A mother suspected of TB coughing and releasing droplet nuclei into the air that could infect other members of the household, particularly children. People with HIV are at greater risk of being infected with TB.

16.1.2  Signs of childhood TB

The clinical picture of pulmonary TB in older children is similar to that of pulmonary tuberculosis in the adult. For older children capable of producing sputum, samples should be collected as for adults. A range of additional physical signs are suggestive of EPTB. These can include swelling over the spine (called a gibbus) and/or an enlargement of the side of the neck, and neck rigidity not responding to treatment with antibiotics. Other signs are abdominal swelling and non-painful enlarged joints. If a child has the symptoms of pulmonary or extra-pulmonary TB, you should refer him or her for investigation.

The diagnosis of TB in younger children (less than a year of age) can be more difficult. One of the indictors that you should be aware of is contact with a family member or close associate with TB. Another key factor in diagnosis is loss of weight and failure to thrive. One of the problems is that children of this age rarely produce sputum and, as you know, this laboratory test is the main method of diagnosis in adults.

In those cases of younger children where you suspect TB, you must tell the family to take the child to a higher health facility for diagnosis. To make the diagnosis of childhood TB with a fair degree of accuracy, one or more of the tests outlined in Box 16.1 are generally followed.

16.1.3  Diagnosis of tuberculosis in HIV-positive children

As in adults, pulmonary TB (PTB) is the most common manifestation of TB in HIV-positive children. The diagnosis of PTB in children under four years old has always been difficult, and infection with HIV makes the effective diagnosis of TB in such cases more challenging.

The approach to diagnosing TB in HIV-infected children is essentially the same as for those children who are HIV-negative, i.e. the presence of three or more of the characteristic symptoms indicates a diagnosis of TB. It is especially important to look for chronic symptoms suggestive of TB, and for physical signs that are highly suggestive of TB — including the results of chest X-ray findings (refer to Study Session 14). Children who present with chronic symptoms suggestive of TB also need testing for HIV infection.

16.1.4  Treatment of tuberculosis in children

As you read in Study Session 13, DOTS (Directly Observed Treatment, Short-course) should be used for all children with tuberculosis. Even when drugs are given under DOTS, tolerance of the medications must be closely monitored. Do not rely solely upon the parents of the child to supervise DOTS; you are responsible for monitoring.

Table 16.1 show different categories of TB cases that you are already familiar with, together with the drug treatment regimen required in children (the number of months for each treatment is indicated by the number in front of the bracket containing the drug combination).

16.1.5  Management of TB in HIV-infected children

Children with TB should be screened for HIV; likewise, HIV-positive children should also be investigated for TB. International guidelines recommend that TB in HIV-infected children should be treated using a six-month drug regimen similar to that used for HIV-negative children; however rifampicin should be given for the entire duration of treatment. It has been found in HIV-infected adults that higher relapse rates occur when ethambutol is used in the continuation phase.

16.1.6  Follow-up and referral of children with TB

As a health worker, you will need to do all you can to administer the chosen treatment and ensure that patients adhere to what they have been told to do. Many children with TB can be managed on an out-patient basis. However, some conditions, such as TB meningitis and other types of EPTB where the infection has spread to organs of the body other than the lung, may require hospitalisation, usually for the first two months of anti-TB treatment. If you find cases where children have respiratory distress, TB involving the spinal cord or they develop severe side effects, they should also be referred to a hospital.

At a minimum, follow-up should include an assessment of symptoms, an evaluation of adherence, an inquiry about any adverse events or side-effects, and the weight of the child should be measured. If the child is losing or gaining weight, they should be referred, because it may be necessary to adjust their medication. As with adult patients, children who were smear-positive for TB at the beginning of treatment should be referred for follow-up sputum smear microscopy at two months, five months, six months and eight months. A child who is not responding to TB treatment should also be referred for further assessment and management.

16.2  TB/HIV co-infection

A person not infected with HIV usually has some natural immunity against tuberculosis. However, the HIV-infected person will be more vulnerable to infection because they will have lost some of their natural immunity. This provides the TB bacteria with a favourable environment in which to multiply and bring about the full disease, showing all the common signs and symptoms. Raising awareness of TB/HIV co-infection is an important role for all health workers (Figure 16.2).

Figure 16.2  Poster campaign to raise awareness of TB/HIV co-infection. (Source: Center for Disease Control and Prevention, USA, accessed from: http://apps.nlm.nih.gov/ againsttheodds/ exhibit/ action_on_aids/ new_disease.cfm )

16.2.1  Effect of HIV on tuberculosis

Ethiopia has one of the highest levels of TB/HIV co-infection in Africa. The WHO Global Report of 2008 estimates that in Ethiopia, 40% of TB patients tested for HIV were HIV-positive, while routine data from 1999 EFY (2006/7) estimates that as many as 31% of TB patients were co-infected with HIV.

HIV increases the risk of infection with M. tuberculosis, and more importantly, increases the risk of progression to TB disease, and hence the incidence and prevalence of active TB. In addition, the HIV pandemic has led to an increase in the number of patients developing side-effects to anti-TB drug treatment. This has produced an increase in the workload for healthcare providers, which can compromise the quality of service and deplete resources. It has also been found that latent TB infection in HIV-positive persons reactivates at a rate of 10% per year, as opposed to 5–10% over a lifetime for HIV-negative persons. HIV-positive persons are prone to re-infection with new strains of TB from the community, and drug resistance may occur more frequently in TB/HIV co-infections.

16.2.2  Effect of tuberculosis on people living with HIV

TB is the leading cause of illness and death among people living with HIV (PLHIV). It increases the occurrence of other infections, increases the rate at which HIV progresses, and influences antiretroviral therapy (ART) in various ways. Late diagnosis and delayed treatment of TB contributes to increased death rates in PLHIV.

A new strategy for tuberculosis control in high-HIV prevalence populations has been developed and the various approaches are summarised in Box 16.2.

16.2.3  TB classification in HIV-positive patients

Classification of TB for those individuals who are also HIV-positive differs slightly from the classification categories described in Study Session 14. They are all category I patients, but can be further classified into one of three revised sub-categories. This revision was introduced by the WHO in 2009 and you will need to be aware of these revised categories for registration and the follow-up of patients with both diseases. The revised sub-categories are listed below:

• a.Smear-positive pulmonary tuberculosis (one or more sputum smears found to be positive for TB bacteria)
• b.Smear-negative pulmonary tuberculosis
• c.Extra-pulmonary tuberculosis.

16.2.4  Diagnosis of TB in HIV-positive patients

The following methods are used for diagnosis of TB in HIV patients; whenever you suspect patients having both diseases you need to send them for investigation.

16.2.5  Prevention and management of TB among PLHIV

• Isoniazid preventive therapy (IPT): IPT is given to HIV patients after investigation where there is no evidence of TB. It is given for six months; you are expected to follow those patients on IPT for adherence and possible side-effects.
• Cotrimoxazole preventive therapy (CPT): It is well-documented that administration of CPT decreases illness and deaths among HIV-infected TB patients. Cotrimoxazole is given for this category of patients and to all HIV-positive TB patients.

• Sometimes TB drugs and ART can produce adverse reactions that may worsen or cause new infections. Patients should be advised to continue their medication and report any problems.

16.3  Drug-resistant TB and multi-drug resistant TB

The emergence of resistance to anti-tuberculosis drugs, and particularly of multidrug resistant-TB (MDR-TB) arises when TB bacteria develop resistance to rifampicin and isoniazid. MDR-TB has become a major public health problem in a number of countries and an obstacle to effective global TB control. When a patient has TB with bacteria that are no longer sensitive to one or more anti-TB drugs, for instance isoniazid, using this antibiotic will not be helpful. Other drugs (known as second-line drugs) have to be used instead of the first-line drug regimens.

A good TB control programme — especially with regard to patient follow-up and adherence, will not generate much drug resistance. Resistance to TB drugs usually occurs as a consequence of inadequate treatment, be it irregular, too short or too weak. Resistant TB bacteria can be transmitted to other people like any other form of TB.

16.3.1  Drug sensitivity testing (DST)

Drug sensitivity testing (DST), performed in a reference laboratory, is the only means by which resistance to anti-TB drug(s) can be confirmed. DST involves growing TB bacteria and treating the culture with one or more anti-TB drugs and seeing if the bacteria are killed or not. If the bacteria are not killed by giving the drug(s), they are considered resistant.

Table 16.2 makes the point that there are three sources for the development of drug resistance. The first and most important category reflects shortcomings by health providers — they can give an inadequate drug regimen, or the wrong guidelines, or they can fail to treat correctly through lack of training and a poor monitoring system. The second category is related to the drugs themselves — they can be of poor quality, in short supply or they can be poorly stored. The last factor contributing to the development of drug resistance relates to the TB patients themselves, and reflects factors such as poor adherence, lack of information about the disease and the influence of social barriers, any one of which can result in patients discontinuing the drugs.

Treatment of MDR-TB is more complicated and takes longer than treatment of TB that is not resistant to the first-line drugs. In Ethiopia, the management of MDR-TB is currently available only at St Peter Specialized TB hospital, but there are plans to expand provision to other regions. As a health worker, the most significant way in which you can help now and in the years ahead is to do all you can to ensure that patients adhere to their treatment, in order to increase the number of cured cases and reduce the incidence of drug-resistant TB.

Summary of Study Session 16

In Study Session 16, you have learned that:

1. Children are usually infected with TB by an adult or an older child with sputum smear-positive PTB, often a family member.
2. The best way to prevent childhood TB is therefore by proper identification and treatment of infectious patients, but diagnosis can be difficult for younger children not able to produce sputum.
3. The DOTS strategy is applicable to all patients with TB, including children and those with TB/HIV co-infection.
4. TB is a leading cause of morbidity and mortality, and the spread of HIV has increased the TB epidemic in Ethiopia. HIV increases risk to infection with M. tuberculosis, the risk of progression to TB disease, and the incidence and prevalence of TB.
5. All patients diagnosed with TB should be encouraged to undergo counselling and testing for HIV, and all HIV-positive patients should be screened for TB.
6. Sputum smear microscopy remains the main method to confirm a diagnosis of pulmonary TB, including in HIV-positive patients. It also helps in identifying infectious patients so that transmission can be stopped.
7. Most of the time, drug-resistant TB is due to inadequate treatment, poor adherence to drug regimens, poor quality or insufficient drugs, and lack of training of healthcare providers in drug prescribing, monitoring and follow-up.
8. For all TB patients, do all you can to ensure adherence to drug regimens, which will reduce the prevalence of TB, including the drug-resistant forms.

Self-Assessment Questions (SAQs) for Study Session 16

Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering these questions. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions at the end of this Module.