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Tuberculosis - Dissertation Sample

14 Mar 2017Dissertation Samples

Can directly observed therapy prevent the re-emergence of tuberculosis in northern England?

The Department of Health reports that tuberculosis cases have increased by 25% in the last 10 years with 6500 cases reported each year.

Tuberculosis or TB is an infectious disease and is caused by a kind of bacteria known as Mycobacterium tuberculosis better known as the tubercle bacillus. TB is typically a disease of the lungs but can affect other parts of the body.

The disease spreads from an infected person through coughing, sneezing and some amount of prolonged close contact with another person. The disease however is not highly contagious and it may even take some years for an infected person to develop the disease completely. TB can be cured if special antibiotics for the disease are taken for a course of 6 months. The most effective method of controlling the spread of the disease is by identification of the TB victims who already have the disease, providing them with proper treatment to cure the infection and to prevent the disease from spreading any further (DH, 2005).

Although under some medical control, TB is still a massive clinical problem. Cases of tuberculosis in England were high in the 1960s and 70s although there was a progressive decline in the number of tuberculosis cases until the mid 1980s with a rise in cases of TB again from 1990s.

In this article we discuss the problems associated with the disease, signs, symptoms and cases highlighting special case studies of tuberculosis with England. We focus our discussion on tuberculosis cases as seen in Northern England and analyze the incidence of TB from the perspective of incidence rate. If there is a re-emergence of tuberculosis as apparent from health reports and clinical studies, we would seek to analyze why this has been the case and the relevance of a rise in the number of cases of tuberculosis in Northern England. In our analysis we will provide several studies on tuberculosis, its control methods and the DH initiatives, action plan and measures to tackle the problem.

We also discuss in depth certain case studies to evaluate whether directly observed therapy can be used more effectively than conventional and self administered therapy for prevention and treatment of tuberculosis.

Chapter 2 - Background and Literature Search:

According to the DH fact file giving statistical data and prevalence of tuberculosis in England, (Source. DH, 2004)

• Tuberculosis (TB) is a serious, but treatable, infectious disease

• TB in England increased by 25 per cent over the last ten years and is still rising; over 1700 more cases occur each year than in 1987 when TB was at its lowest. The disease has thus been recorded at its lowest incidence rate in 1987 and in the past decade or so there has been a drastic re-emergence of TB in England.

• 6638 people were newly diagnosed with TB in England in the year 2002. That is 13 for every 100,000 people in our population – this is fewer than some countries, but more than several other western European countries where TB rates in 2001 ranged from 5 to 44 per 100,000 population

• About as many people in England develop TB each year as now become infected with HIV. A relation between TB and HIV can be established as occurrence of HIV of infection can lead to increased vulnerability to TB.

• Every year around 350 people in England die from TB

• Most TB in England occurs among people who live in inner cities. Two out of every five cases are in London. The disease has doubled in London in the last ten years and a few London boroughs now have TB rates comparable with some developing countries

• People are at higher risk of TB if they have lived in parts of the world where TB is more common. The disease follows patterns of migration and is therefore more common in certain ethnic groups, especially if they were born abroad:

in England, around seven out of every ten people with TB come from an ethnic

minority population group

nearly two thirds of our TB patients were born abroad

about half of the TB patients who were born abroad are diagnosed with the disease within five years of first entering the UK

HIV infection weakens a person’s immunity to TB. In England, this overlap is still relatively small compared to other parts of the world, but at least three per cent of people with TB are estimated to be HIV positive (this rate is even higher in London)

• TB in cattle – bovine TB – is increasing in England. Very few human cases are due to this bovine form, but continued vigilance is required to prevent transmission from cattle to human

• TB can be controlled by:

 promptly recognizing and treating people with the disease

> ensuring that people with the disease complete their treatment. Lapses on treatment not only fails to cure the disease but contributes to the growth of drug resistance and spread of the disease

The following table gives the TB risk from contact with an infected person and the duration of exposure is also important–  

Source: New England Journal of Medicine 2003; 348:125666, DH, 2004.

According to Tandon et al (2002) tuberculosis is a major public health problem in any developing country and is made worse by poor adherence to treatment schedules and frequent interruption in the method of treatment such as taking proper medication. Tandon et al emphasize that treatment of tuberculosis requires following a strict schedule and to maintain a clinical treatment discipline in order to eradicate the active and passive mycobacteria and to cure the disease completely.

In the analysis of the manifestation of TB and its occurrence we discuss all these issues in greater detail and give evidential studies to prove out point and the summary provided by the Department of Health. TB has been found to be more common among the ethnic minority group, within London and lapses in treatment or diagnosis of TB lead to drug resistance that can impede treatment. Considering the causes and factors that lead to TB and the barriers identified in the treatment of TB are discussed along with a critical examination of the effectiveness of the directly observed therapy or DOT in tuberculosis treatment. We examine this in the context of the reemergence of TB in recent years and how this relates to special contextual situations like Northern England.

For our purposes we conduct a literature search on the causes, factors and manifestation of TB, the relationship of TB to HIV and multi-drug resistance, how this affects treatment and how TB could be treated effectively and what actions should be taken to control the spread of the infection. The relevance of the directly observed therapy as against conventional self-administered therapy is discussed in terms of the cost effectiveness and duration of treatment using different approaches. We search Medline, Science direct and other medical and nursing journal databases and used search terms as ‘direct observed therapy’; ‘tuberculosis’, or ‘tuberculosis England’. We provide an analysis of our findings below and study the relevance of the Department of Health Action plan in the context of these evidential clinical studies.

Chapter 3 - Tuberculosis – Evidential Studies:

In this section we take our discussion a step forward by identifying the reasons, causes of tuberculosis and how it manifests itself. The implications of HIV infection and multi-drug resistance in tuberculosis are discussed along with the role of vitamin D in the onset of the disease. The differences between adult and childhood tuberculosis and the importance of controlling the spread of the disease are also discussed along with the factors delineated by the Department of Health as contributing to transmission of the infection even in healthcare facilities.

The Department of Health has clearly differentiated between HIV (Human immunodeficiency virus) related tuberculosis and Drug resistant tuberculosis. Although these are separate factors that affect infected persons, special care should be taken to prevent any interaction between persons with HIV and persons suffering from tuberculosis. HIV infected individuals are more vulnerable to such infectious diseases and the transfer of disease from Drug resistant to HIV resistant patients can be common. In fact in many countries people affected with HIV have been found to be affected with tuberculosis as well; tuberculosis is the most common co-infection with HIV (Department of Health, 1998) and develops more rapidly in HIV infected patients. In 1991 Horner and Moss reported that persons with AIDS or PWAs are 100 times more likely to develop tuberculosis than the general population. TB incidence rates in the US are high among drug users and range from 4-21% and in London 25% of AIDS patients have been found to have tuberculosis as well.

In AIDS patients there is especially a reactivation of a latent tuberculosis infection due to failure of the immune system and TB develops through reactivation or exogenous primary infection. Risks are high for HIV sero-negative patients and TB manifests itself in early stages of HIV infection and the symptoms of TB and HIV patients include fever, weight loss, malaise, cough accompanied with labored/difficult breathing, an atypical chest radiograph, and extra-pulmonary TB. Delays in diagnosis and treatment are common and many sputum samples may not immediately test positive for Mycobacterium tuberculosis so treatment should begin immediately.

Some studies have demonstrated that isoniazid prophylaxis substantially decreases the incidence of TB in HIV sero-positive patients in Zambia. Horner and Moss (as cited by DH, 2004) report that there is no conclusive evidence of the harm or even effectiveness of the BCG vaccine in HIV children and adults although BCG has been widely regarded as capable of preventing the possibility of tuberculosis.

HIV infection by itself does not cause tuberculosis but it makes a person vulnerable and increases the risk of acquiring tuberculosis almost by 100 times, if the person is exposed to tuberculosis bacteria. Thus compared with an immuno-competent person, a person with immunodeficiency due to lack of resistance and immunizing capabilities fall prey to tuberculosis easily. This is also true in case of drug resistant tuberculosis, which make individuals more vulnerable than persons affected by drug sensitive tuberculosis.

Drug resistant tuberculosis is common in many developed countries as well when it was discovered through chemotherapy that resistant strains of tuberculosis bacteria emerged rapidly despite treatment and instead of one drug, a combination of several drugs had to be used for treatment of tuberculosis. Drug resistance in tuberculosis is the result of poor treatment and inadequate control measures. The DH states that in 1996, within England and Wales, 6.1% of initial isolates of M. tuberculosis were resistant to the drug isoniazid and 1.8% were resistant to rifampicin; 1.6% were multiple drug-resistant. According to the Department of Health, this statistic represents a small but significant increase in drug resistant tuberculosis since 1993. Drug resistant diseases are more difficult to treat and pose greater challenges and threats than drug sensitive diseases. Prevention of the emergence of drug resistant strains of tuberculosis is one of the stated aims of the Department of Health national tuberculosis policy.

Conaty et al (2004) distinguished between primary and secondary drug resistance. They defined primary drug resistance as that which is transmitted and secondary drug resistance as that which develops during the course of treatment. The risk factors for each type of resistance were evaluated. Patients in England and Wales with isoniazid- and multidrug-resistant tuberculosis were compared. All the patients studied between 1993-1994 and 1998-2000 had fully sensitive tuberculosis and were examined separately based on the criterion of whether they has previous attacks of the diseases.

The study indicated that patients with previous tuberculosis smear positivity in the tests and a combination of this with less than 5 years of arrival in the UK were strongly associated multidrug resistance and isoniazid resistance. In patients with no previous tuberculosis infection or an existing HIV infection, foreign birth were found to be risk factors for multidrug resistance. For people of non-white ethnicity, HIV infection was instrumental for isoniazid resistance. Thus risk factors for each type of resistance seem to differ and elevated risks have been found with residence in London, HIV positivity and ethnicity if there were no records of previous tuberculosis. Thus presence of previous tuberculosis, and HIV infection increases the prevalence of multidrug resistant tuberculosis in a certain ethnic group.

In one of the clear evidential studies on tuberculosis Jenkins (2005) examined rifampicin resistance in tuberculosis outbreak in a London hospital. In this study, Mycobacterium tuberculosis isolates were cultured from 6 patients who were associated with isoniazid-resistant M. tuberculosis outbreak and showed symptoms of such. This strain of mycobacterium was also found to acquire rifampicin resistance. The rpoB gene sequence revealed that this resistance can e traced to some rare mutations in each of the isolates. Three isolates were found to have a mutation outside the rifampicin resistance-determining region (Jenkins, 2005).

This brings us to the question of detailed analysis of isolates of Mycobacterium, their origins and properties. Dale et al (2005) used isolates of Mycobacterium tuberculosis from a population-based study in London and these isolates were assigned 12 groups, superfamilies or sfams. Analysis of patient data suggested that there are clear geographical associations in the distribution of these sfams in the population. For example, isolates obtained from Europe born patients were from different sfams than those who were born elsewhere showing that possibilities of transmission of tuberculosis from immigrant communities into endogenous population is usually rare. Yet certain multivariate and statistical analysis showed that some sfams were found independent of the country of birth or ethnicity of individuals and were significantly associated with pulmonary rather than extrapulmonary diseases with sputum smear negativity. This suggested that the properties of the infecting organism play a role in the nature and manifestation of the disease process.

Vitamin D deficiencies have also been associated with tuberculosis and in a study by Ustianowski et al (2005) an analysis has been done on the associations and prevalence of vitamin D deficiency with tuberculosis which is high in foreign born persons resident in developed countries. This study forms a helpful guide and helps determine the associations and incidence of vitamin D deficiency in TB patients at an infectious disease unit in an England hospital.

Vitamin D is important in the host as a defense against TB and any deficiency of the vitamin can become an acquired risk factor for the disease. For the purposes of the study, 210 patients diagnosed with TB had their plasma vitamin D levels measured routinely. Prevalence of vitamin D deficiency, and its relationship to ethnic origin, religion, site of TB, sex, age, duration of stay in the UK and the months of estimation, and TB diagnosis were determined. Among the patients 76% were deficient but many had undetectable levels of deficiency.

Asians were found to have low levels of the vitamin and thus although there has been significant association between the vitamin deficiency and the ethnicity or birth origin no differences were found between the site of TB and the duration of residence in the UK. The authors concluded that Vitamin D deficiency commonly associates with TB among all ethnic groups apart from White Europeans and South East Asians. Lack of sunlight exposure and an exclusively vegetarian diet are factors that can lead to this deficiency. The factors identified by the Department of Health as having contributed to the transmission of the infection in HIV settings or healthcare facilities are:

• delay in considering the diagnosis of tuberculosis;

• delay in confirming the diagnosis;

• delay in considering and establishing drug-resistance;

• delay in starting treatment;

• treatment with inappropriate drugs (and dosages);

• default from treatment;

• lapses in isolation (eg inappropriate accommodation taking into account the infectiousness or likely infectiousness of the case, the immune status of the surrounding patients/contacts, and any suspected or confirmed drug resistance; the patient wandering from an isolation room into other patient areas; inadequate or incorrect ventilation of isolation rooms);

• performance of aerosol-generating procedures on a patient with (sometimes unsuspected) pulmonary tuberculosis in an open ward containing immunocompromised patients. (DH, 1998)

The Department of Health has also identified that lapse on the part of medical professionals and human fallibility can lead to rapid spread of tuberculosis. The primary elements in the control of tuberculosis are

1. Prompt recognition, confirmation and treatment of cases

2. Using certain infection control measures to reduce airborne spread of infection from infectious patients to others.

3. A Team approach for effective control and decision making

4. Establishing close working relationships, between health care workers, and between all involved in the care of an individual patient, in particular between the TB physician, HIV physician, microbiologist, hospital infection control doctor and team, TB nurse specialist and the consultant in communicable disease control who has overall responsibility for tuberculosis control.

Childhood cases of tuberculosis should be specifically studied as 40% of all cases of tuberculosis are reported in children. The control of TB is an important health agenda and is an issue of global importance although no complete control of the disease can either be promised or expected at present. Adult tuberculosis has been thought to be related to childhood tuberculosis and it is also recognized that the infection acquired during childhood promotes reactivation of adult disease maintaining the chain of transmission. This proves that childhood tuberculosis needs equal or more attention for effective control. Treatment procedures include early diagnosis and ensuring treatment compliance. Inaccessible sites for bacteriological confirmation and small number of bacilli make diagnoses of childhood tuberculosis a difficult process and for detection circumstantial evidence is used as the basis (Amdekar, 2005).

Clinical manifestations of tuberculosis in childhood are based on immune responses of the host and the degree of virulence of the tubercle bacilli and no typical manifestations or clinical presentations can be delineated. Thus many children remain undiagnosed and consequently untreated. The conventional test of tuberculin and radiology tests and other modern tests may have limitations and may not be fully dependable. A failure of tuberculosis control program is invariably related to drug resistance and results to poor patient treatment compliance and recovery. So the direct observed treatment or DOTS has been recommended unanimously for the treatment of tuberculosis (Amdekar, 2005). However DOTS is used in less than 40% of tuberculosis cases and misconceptions on TB control and treatment threatens to undermine success of a TB control program which is essentially a clinical management problem. Amdekar (2005) suggests that greater accountability of governments, donors and providers is essential.

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