Clinical Update: Tuberculosis - Professional Communication for Nurses

This clinical update provides a comprehensive overview of tuberculosis (TB), a preventable and controllable respiratory infection. It delves into the etiology and pathogenesis of TB, detailing the causative bacterial strains like Mycobacterium tuberculosis and associated risk factors such as HIV/AIDS, diabetes, malnutrition, smoking, and age. The report elucidates the pathogenesis, progress, and complications of TB, from initial infection to latent and primary disease stages, including the formation of tubercles and potential for lymphadenopathy. Public health implications are discussed, highlighting the global burden of TB, its impact on mortality and morbidity, and the risk of drug-resistant strains. The clinical manifestations, diagnostic processes (including chest x-rays and sputum smear tests), and pharmacological treatments (such as rifampin, isoniazid, pyrazinamide, and ethambutol) are thoroughly explained. Non-pharmacological interventions and health promotion strategies are also addressed, providing a holistic understanding of TB management and control.

Assignment title: Clinical Update: Tuberculosis
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Table of Contents
Introduction..............................................................................................................1
Discussion................................................................................................................1
Etiology and Pathogenesis...................................................................................1
Causes and Risk Factors..................................................................................1
Pathogenesis, Progress, Complications and Physiology..................................3
Public Health Implications...............................................................................5
Clinical Manifestations........................................................................................5
Diagnostic Process...............................................................................................6
Treatment and Rationale......................................................................................7
Pharmacological Management.........................................................................7
Non-pharmacological Treatment and Health Promotion.................................8
Conclusion...............................................................................................................8
References..............................................................................................................10

Clinical Update: Tuberculosis
Introduction
Tuberculosis (TB) is a preventable and controllable respiratory infection caused due to
inhalation of specific air-borne bacterial pathogens which in turn, can aggravate to long term
pulmonary damage (Lu et al., 2016). According to the World Health Organization (WHO,
2020), TB has been reported as one of leading contributors of global mortality and is known
to have contributed to 1.5 million deaths worldwide during 2018. The global prevalence of
TB in 2018 was estimated to be 10 million in 2018, with an incidence rate of 6.6/100, 000
within the Australian population (WHO, 2018). If not controlled, TB can inflict long term
economical and public health implications upon a nation’s population (Gagneux, 2018).
Thus, with respect to the above, the following paper aim to provide a comprehensive and
extensive discussion on the underlying pathogenesis, causative and risk factors, clinical
manifestations, appropriate diagnostic procedures and effective treatment strategies for TB
prevention, management and control. The scope of this paper also lies in its ability to briefly
expound upon associated topics of relevance such as the risk of drug resistance, adverse
public health implications and importance of robust health promotional interventions. .
Discussion
Aetiology and Pathogenesis
Causes and Risk Factors
Tuberculosis (TB) is caused by bacterial strains belonging to the genus of
Mycobacterium. Some of the most prevalent bacterial strains of this family which are
responsible for causing TB infection are: Mycobacterium tuberculosis, Mycobacteria bovis
and Mycobacterium africanum. Of these, the bacterial strain Mycobacterium tuberculosis, is
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the most prevalence cause of TB incidences across the world, while the bacterial strain
Mycobacterium africanum has been found to cause a number of cases of the disease in the
African continent (Ai, Ruan, Liu & Zhang, 2016). One of the rarest types of bacterial strains,
that is, Mycobacteria bovis has been evidenced to cause TB infection across cattle and has
been found to infect humans via the consumption of unpasteurized and contaminated dairy
and dairy products acquired from the infected animal (Mai et al., 2019).
While infection by Mycobacterium strains is the most common cause of TB, specific
risk factors, such as a damaged immune system, may increase the risk of TB caused due to
this microorganism in individuals (WHO, 2020). Some of these risk factors are the following:
1. HIV/AIDS: According to the World Health Organization (WHO, 2020), the risk of
developing TB is 15 to 22 times higher across individuals who are HIV positive, due
to their already comprised immune system. Approximately 251, 000 reports of deaths
as a result of a dual diagnosis of TB and HIV/AIDS. The highest prevalence of such
dual disease incidence, which is 84%, has been reported in the Sub-Saharan African
region during the year 2018.
2. Diabetes: The risk of developing TB is approximately thrice across individuals with
diabetes mellitus. Lack of adequate control of glycemic levels can facilitate the
prognosis of TB and thus, requires frequent monitoring and management for
prevention (Restrepo, 2018).
3. Malnutrition: Malnutrition, the condition of inadequate dietary intake and nutritional
status, is likely to be associated with poor stores of essential micro and
macronutrients, which in turn, compromises the ability of the immune system to
defend from individuals. This results in higher TB risk across malnourished
individuals (Chandrasekaran, P., Saravanan, Bethunaickan & Tripathy, 2017).
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4. Smoking and alcohol: Individuals who engage in unhealthy lifestyle behaviors, such
as smoking and alcohol are twice and thrice as likely to develop TB. Smoking and
alcohol are associated with increased rates of nutrient depletion and inflammation
associated-oxidative stress, resulting in weakened immune functioning and higher risk
of acquiring TB (Silva et al., 2018).
5. Age: Infants and the elderly, due to their developing and already-weakened immune
system, are at higher risk of acquiring TB (Qian et al., 2018).
6. Medications: Specific medications like chemotherapy and corticosteroids, if taken for
an extensive period of time, are likely to be at risk of TB. Individuals undergo organ
transplants, are required to take medications like immune-suppressants, which weaken
the immune system ad increase risk of TB. Additionally, anti-inflammatory
medications like tumour necrosis factor (TNF) inhibitors, taken for autoimmune
diseases like rheumatoid arthritis, may increase TB risk (Silva et al., 2018).
7. Geography: Individuals belonging to countries which have reported high rates of TB
incidences, such as India, Bangladesh, Indonesia, China, South Africa, Philippines,
Nigeria and Pakistan, are at higher risk of acquiring TB (Qian et al., 2018).
Pathogenesis, Progress, Complications and Physiology
Since TB is a respiratory disease, the most common organs affected by TB are the
lungs. The pathology of TB is largely associated with the inhalation of droplet nuclei –
minute particles of air infected with Mycobacterium tuberculosis. The subsequent
transmission occurs as a result of a health individual being exposed to sputum inhalation
released by infected individuals in the formed of coughing, talking or sneezing (Ravimohan,
Kornfeld, Weissman & Bisson, 2018). The pathogenesis, progress and complications
associated with TB can be segregated into four parts, namely:
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1. Prompt clearance of the bacteria by the immune system.
2. Latent TB: A condition associated with the persistent stimulation of immunological
responses towards antigens of the inhaled infected bacteria, without however clinical
manifestations of the signs and symptoms. Lack of mitigation can progress to primary
disease stages
3. Primary disease: The stage of active TB infection
4. Reactivation: Relapse of the infection after a significant time period (Ravimohan,
Kornfeld, Weissman & Bisson, 2018).
The key pathology of TB occurs during primary disease stages. Upon inhalation and
settlement of bacilli in the spaces of the alveolar sac, the immunological defense mechanisms
are triggered via release of macrophages. Inability to fight off the infection results in the
bacilli infecting the macrophages further contributing to the release of pro-inflammatory
chemokines and cytokines (Rodriguez-Takeuchi, Renjifo & Medina, 2019). The resultant
disease progresses is associated with the release of additional alveriolar macrophages,
neutrophils and monocytes which in turn form a tubercle or a granulomatous, nodular
structure within the parenchyma of the lung. Inability to ward off the infection at this stage
results enlargement of the tubercle to progress into the surrounding lymph nodes
(Ravimohan, Kornfeld, Weissman & Bisson, 2018). This results in the complication of
lymphadenopathy or associated lesions across the lymph nodes and lung parenchyma as a
result of TB progress. Lack of mitigation contribute to further disease progress associated
with inflammatory release of reactive oxygen species, tumour necrosis factor (TNF)-alpha,
and cytotoxic cells such as perforin and granzymes. The substances contribute to
complications like alveolar destruction, necrosis and development of scar tissue in the lungs
(Sharma & Sarkar, 2018).
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Public Health Implications
As discussed previously, nations with high incidence of the infection and particularly
low income group countries where malnutrition is rampant, the risk of TB is alarming.
Considering the infectious nature of TB transmission, if not controlled, this illness can inflict
public health implications in the form of a rising burden of preventable diseases and
increasing rates of mortality and morbidity. High rates of mortality and morbidity, coupled
with additional complications like malnutrition as observed in developed countries are
prevalently associated with a population with poor health outcomes resulting in a nation with
poor economic growth (Golli et al., 2019).
Additionally, economically underprivileged populations, are also likely to encounter
additional issues like reduced accessibility and availability of healthcare resources and
services, reduced public health awareness as well as reduced financial ability to afford quality
treatment of TB (Hamblion et al., 2019). These factors may contribute to inadequate TB
antimicrobial compliance, resulting in another emerging public health issue – the acquisition
of drug resistant versions of TB. Such infections are associated with longer hospital periods
and lack of tolerance of prevalent surgical procedures like transplants and caesarean births
resulting in higher medical costs and national financial burden. Thus, lack of mitigation of
TB is associated with farfetched and adverse public health implications worldwide (Schön et
al., 2017).
Clinical Manifestations
Latent forms of the infection are generally asymptomatic. Active of primary stages of
the infection are associated with symptoms like: shortness of breath, pain in the chest and a
persistent cough lasting for approximately 3 weeks or more. As the disease progresses and is
accompanied by pulmonary inflammation and destruction of pulmonary tissues, prevalent
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symptoms include: cough associated with blood and mucous and feelings of fatigue, fever,
loss of appetite, weight loss, hypothermia and sweating at night. Additional symptoms like
pain in joints may be indicative of transmission of TB across surrounding organs like the
bone (van Kampen et al., 2019).
Diagnostic Process
Since the first stage of active TB is associated with the lungs, preliminary diagnostic
processed include pulmonary radiological examinations, like x-rays of the chest. Chest x-ray
images which reflect multiple nodular infiltrates in the upper or middle clavicles and
pulmonary spaces are indicative of TB infection since the same is associated with tubercle
formation and lymphadenopathy due to disease progression. Additional prevalently used
diagnostic procedures for TB include sputum smear testing for examination of
Mycobacterium cultures – the key bacteria strains responsible for the infection (Datta,
Saunders, Tovar & Evans, 2017). However common systematic errors in this tests include
the inability to detect less than 10,000 bacilli/mL of sputum and inconsistent Gram stain
uptake by the bacteria. This calls for specific diagnostic examinations like Interferon Gamma
Release Assay (IGRA) which is associated blood tests examining the prevalence of
inflammatory, immunological responses due to TB – reflective of the initial macrophage
associated defense stages upon bacterial infiltration in the alveolar spaces. This test is
sensitive enough to detect the prevalence of latent TB infection in suspected individuals
(Dheda et al., 2017).
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Treatment and Rationale
Pharmacological Management
Prevalent pharmacological interventions for TB include an antibiotic course ranging
from 6 to almost 9 months, comprising of 4 drugs namely: rifampin (RIF, with a dosage of
10mg/kg body weight), isoniazid (INH, with a dosage of 5mg/kg body weight), pyrazinamide
(PZA, with a dosage ranging from 1000 to 2000 mg for body weights ranging from 40 to
more than 90kg) and ethambutol (EMB, with dosage ranging from 800 to 1600 mg for body
weights ranging from 40 to more than 90 kg) (Nagarajan & Whitaker, 2018).
Rifampin’s mechanism of action is associated with inhibition of the synthesis of
bacterial genetic material like RNA via blocking RNA polymerase functioning. This results
in lack of bacterial DNA formation and synthesis of proteins essential for bacterial survival
resulting in decreased microbial proliferation. The mechanism of action of isoniazid is
associated with inhibition of mycolic acid synthesis required for development of cell walls
and resultant death of mycobacterial straisn (Nguyen, 2016). For pyrazinamide, the
mechanism of action includes increased pyrazinamidase enzyme functioning resulting in
greater conversion of pyrazinamide to pyrazinoic acid which accumulates in bacterial cells to
inhibit the formation of essential fatty acid and ribosomal proteins. Ethambutol exerts its
mechanism of action via inhibition of enzyme arabinosyl transferase responsible for synthesis
of essential mycobacterial cell wall components like arabinogalactan. Prevalent side effects
of these drugs include: gastrointestinal disturbances, nausea, heartburn, headaches, menstrual
irregularities and abnormal yellowing or color changes observed in saliva, sweat or urine
(Nagarajan & Whitaker, 2018).
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Non-pharmacological Treatment and Health Promotion
In addition to the above, the action of medications can be facilitated by non-
pharmacological interventions like maintenance of strict hand hygiene and contact
precautions for disease transmission prevention. Additionally, healthcare professionals are
advised to engage in strict personal and organizational disinfection protocols, usage of
personal protective equipment like gloves and masks during patient management and patient
isolation for disease prevention (Pinto, Nepomuceno & Campanharo, 2019). Additionally,
the nutritional intake of patients must be monitored via dietary assessments coupled with the
consumption of a balanced diet with multivitamin supplements for malnutrition mitigation
and faster recovery (Shaji, Thomas & Sasidharan, 2019).
The prevalence of drug resistant and relapsed forms of TB are largely associated with
poor health literacy resulting in inadequate compliance to specified medication regimens. To
prevent the same, the establishment of effective health promotional interventions are
required. This can include healthcare professionals teaching and providing patients and
families with patient-centered resources containing TB details, implications, medication
protocols and hygiene associated prevention strategies (Falzon et al., 2017). Additionally,
public health organizations and policy makers should collaborate to develop community and
public health campaigns, resources and advertisements educating the effects of TB, strategies
for prevention and importance of compliance to medication, nutrition and hygiene protocols
(Shah, Poojari & Meshram, 2020).
Conclusion
This paper thus provides a comprehensive and detailed discussion on the key
pathologies, causative factors and clinical complications associated with TB. While the
manifestations of TB are adverse, engagement in adequate treatment and prevention can
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contribute to its management. The public health implications of TB such as economic impact,
disease burden and drug resistant infections are likely to be higher in economically
underprivileged countries. There is thus a need for development of robust public health
policies and educational campaigns to increase public awareness and disease prevention at
the national level.
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