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group_1_presentation_2_-_global_burden_of_disease_respiratory_infections [2017/03/10 21:37]
wardhaw
group_1_presentation_2_-_global_burden_of_disease_respiratory_infections [2018/01/25 15:18] (current)
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 Unfortunately,​ Canada is not immune to the detrimental impact of LRTIs. In fact, Inuit infants within Canada have some of highest hospital admissions as a result of LRTIs in the entire world (Kovesi et al., 2007). More specifically,​ a recent study found that the annualized incidence rate of admission to hospital for LRTI for a particular Inuit population located on Baffin Island was 484 per 1000 infants under the age of 6 months (Banerji et al., 2001). After extensive research, it was determined that indoor air pollution, reduced ventilation,​ and overcrowding within a household are all risk factors associated with LRTI that are prevalent in most Inuit communities in Canada (Kovesi et al., 2007). ​ Unfortunately,​ Canada is not immune to the detrimental impact of LRTIs. In fact, Inuit infants within Canada have some of highest hospital admissions as a result of LRTIs in the entire world (Kovesi et al., 2007). More specifically,​ a recent study found that the annualized incidence rate of admission to hospital for LRTI for a particular Inuit population located on Baffin Island was 484 per 1000 infants under the age of 6 months (Banerji et al., 2001). After extensive research, it was determined that indoor air pollution, reduced ventilation,​ and overcrowding within a household are all risk factors associated with LRTI that are prevalent in most Inuit communities in Canada (Kovesi et al., 2007). ​
-<​box ​51% round| > {{:​Baffin.png|}} </box| Figure 2 : Baffin Island, which has some of the worst LRTI rates in the world. Retrieved from: https://​encrypted-tbn3.gstatic.com/​images?​q=tbn:​ANd9GcQ3VU-2zllZKj0gv4Ww9NXrTf7mXMTXZVvW7_G-yR5OElvwp_HSm-bes9Y+<​box ​56% round| > {{:​Baffin.png|}} </box| Figure 2 : Baffin Island, which has some of the worst LRTI rates in the world. Retrieved from: https://​encrypted-tbn3.gstatic.com/​images?​q=tbn:​ANd9GcQ3VU-2zllZKj0gv4Ww9NXrTf7mXMTXZVvW7_G-yR5OElvwp_HSm-bes9Y
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 ====== Pathophysiology ====== ====== Pathophysiology ======
  
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 The primary function of the respiratory system is to exchange oxygen and carbon dioxide between the body and environment,​ and it takes place in the alveoli, also known as air sacs found in the lungs (Inglis, 2007). Therefore, the respiratory tract is constantly exposed to microorganisms such as bacteria, viruses, and fungi. The majority of particles are filtered out in the nasal hairs and by the inertial impaction, which is covered by mucus found in the posterior nasopharynx. The epiglottis applies a closure and cough reflex to reduce the risk of microorganisms reaching the lower respiratory tract. However, if small enough particles have reached the trachea and bronchi they then stick to the respiratory mucus lining their walls and are propelled towards the oropharynx by the cilia. Then, antimicrobial factors such as lysozyme, lactoferrin and secretory IgA present in respiratory secretions disable inhaled microorganisms from reaching further into the lungs (Inglis, 2007). ​ The primary function of the respiratory system is to exchange oxygen and carbon dioxide between the body and environment,​ and it takes place in the alveoli, also known as air sacs found in the lungs (Inglis, 2007). Therefore, the respiratory tract is constantly exposed to microorganisms such as bacteria, viruses, and fungi. The majority of particles are filtered out in the nasal hairs and by the inertial impaction, which is covered by mucus found in the posterior nasopharynx. The epiglottis applies a closure and cough reflex to reduce the risk of microorganisms reaching the lower respiratory tract. However, if small enough particles have reached the trachea and bronchi they then stick to the respiratory mucus lining their walls and are propelled towards the oropharynx by the cilia. Then, antimicrobial factors such as lysozyme, lactoferrin and secretory IgA present in respiratory secretions disable inhaled microorganisms from reaching further into the lungs (Inglis, 2007). ​
  
- <​box ​50% round | > {{:​snip3_2.png}} </​box|Figure 4: Defences of the respiratory tract (Inglis, 2007).>+ <​box ​43% round | > {{:​snip3_2.png}} </​box|Figure 4: Defences of the respiratory tract (Inglis, 2007).>
  
 However, particles ranging from about 5-10 µm may be able to get further into the respiratory system into the alveolar air sacs (Inglis, 2007). Once they reach the alveolar air sacs, the alveolar macrophages phagocytose the pathogens, and the neutrophils may also be activated through the inflammatory response (Inglis, 2007).  ​ However, particles ranging from about 5-10 µm may be able to get further into the respiratory system into the alveolar air sacs (Inglis, 2007). Once they reach the alveolar air sacs, the alveolar macrophages phagocytose the pathogens, and the neutrophils may also be activated through the inflammatory response (Inglis, 2007).  ​
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 Nevertheless,​ pathogens have developed strategies to overcome the defense mechanisms in the respiratory system. For example, Streptococcus pneumonia, a gram-positive bacteria, and Haemophilus influenzae, a gram-negative bacteria both produce an enzyme known as IgA protease, which is capable of disabling mucosal IgA (Inglis, 2007). Streptococcus pneumonia and Haemophilus influenzae which are primarily known to cause pneumonia, in addition to other bacteria are resistant to phagocytosis. Therefore, they are able to get passed the defense mechanisms and penetrate to the lungs. Some microorganisms also release toxins which can cause further damage to the alveolar walls (Inglis, 2007). ​ Nevertheless,​ pathogens have developed strategies to overcome the defense mechanisms in the respiratory system. For example, Streptococcus pneumonia, a gram-positive bacteria, and Haemophilus influenzae, a gram-negative bacteria both produce an enzyme known as IgA protease, which is capable of disabling mucosal IgA (Inglis, 2007). Streptococcus pneumonia and Haemophilus influenzae which are primarily known to cause pneumonia, in addition to other bacteria are resistant to phagocytosis. Therefore, they are able to get passed the defense mechanisms and penetrate to the lungs. Some microorganisms also release toxins which can cause further damage to the alveolar walls (Inglis, 2007). ​
    
-<​box ​23% round right | > {{:​strept.jpeg}} </​box|Figure 5: Streptococcus pneumonia Retrieved from: http://​www.newhealthadvisor.com/​streptococcus-pneumoniae.html>​+<​box ​28% round right | > {{:​strept.jpeg}} </​box|Figure 5: Streptococcus pneumonia Retrieved from: http://​www.newhealthadvisor.com/​streptococcus-pneumoniae.html>​
  
  ​Pneumonia can develop after inhalation of microorganisms primarily bacteria, viruses, and fungi or when bacteria from an infection elsewhere in the body spreads to the lungs, which overpower your immune system, thus infecting your lungs (Mayo Clinic, 2016). It is characterized by inflammation of the air sacs or alveoli, which are microscopic sacs in the lungs that absorb oxygen. The inflammation causes the alveoli to fill with fluid reducing the amount of air space in the lungs for air, and so the air coming is unable to exchange (Mayo Clinic, 2016).  ​Pneumonia can develop after inhalation of microorganisms primarily bacteria, viruses, and fungi or when bacteria from an infection elsewhere in the body spreads to the lungs, which overpower your immune system, thus infecting your lungs (Mayo Clinic, 2016). It is characterized by inflammation of the air sacs or alveoli, which are microscopic sacs in the lungs that absorb oxygen. The inflammation causes the alveoli to fill with fluid reducing the amount of air space in the lungs for air, and so the air coming is unable to exchange (Mayo Clinic, 2016).
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 Ventilator-associated pneumonia is a type of HAP, which occurs in patients receiving mechanical ventilation through an endotracheal tube or tracheostomy (Amanullah, 2015). Thus, the mechanical ventilation increases the risk of developing bacterial pneumonia because it allows free passage of bacteria into the lower segments of the lung through the endotracheal tube and around the cuff which then enters the lungs with each breath (Amanullah, 2015). ​ Ventilator-associated pneumonia is a type of HAP, which occurs in patients receiving mechanical ventilation through an endotracheal tube or tracheostomy (Amanullah, 2015). Thus, the mechanical ventilation increases the risk of developing bacterial pneumonia because it allows free passage of bacteria into the lower segments of the lung through the endotracheal tube and around the cuff which then enters the lungs with each breath (Amanullah, 2015). ​
  
-<​box ​37% round | > {{:​vap.png}} </​box|Figure 7: Ventilator Associated Pneumonia. Retrieved from: http://​speciality.medicaldialogues.in/​preventing-ventilator-associated-pneumonia-in-hospitals-goi-guidelines/>​+<​box ​39% round | > {{:​vap.png}} </​box|Figure 7: Ventilator Associated Pneumonia. Retrieved from: http://​speciality.medicaldialogues.in/​preventing-ventilator-associated-pneumonia-in-hospitals-goi-guidelines/>​
  
  
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 Interestingly,​ the practice guidelines of the American Thoracic Society (AST) and the Infectious Disease Society of America (IDSA) places emphasis on using patient'​s history and physical examination for diagnosis (Carrol, 2002). Lastly, microbiological tests have seen an increase in use due to the ease and accuracy of the tests performed. They require collection of sputum, which is a mixture of saliva and mucus coughed up from the respiratory tract. For example, Streptococcus pneumoniae, the bacteria which causes pneumonia is tested for by performing gram stains and cultures. Also, bacterial urinary antigen tests are available as they are highly specific and sensitive (Carrol, 2002). Overall, physicians rely on traditional methods for diagnosis of the disease, although laboratory tests are favored for their accuracy and ease of specimen collection. ​ Interestingly,​ the practice guidelines of the American Thoracic Society (AST) and the Infectious Disease Society of America (IDSA) places emphasis on using patient'​s history and physical examination for diagnosis (Carrol, 2002). Lastly, microbiological tests have seen an increase in use due to the ease and accuracy of the tests performed. They require collection of sputum, which is a mixture of saliva and mucus coughed up from the respiratory tract. For example, Streptococcus pneumoniae, the bacteria which causes pneumonia is tested for by performing gram stains and cultures. Also, bacterial urinary antigen tests are available as they are highly specific and sensitive (Carrol, 2002). Overall, physicians rely on traditional methods for diagnosis of the disease, although laboratory tests are favored for their accuracy and ease of specimen collection. ​
  
-<​box ​55% round| > {{:​pneumonialungs.png|}} </box| Figure 8: Healthy lungs (LS) vs. lungs affected by pneumonia (RS). Retrieved from: https://​www.med-ed.virginia.edu/​courses/​rad/​cxr/​pathology3chest.html >+<​box ​60% round| > {{:​pneumonialungs.png|}} </box| Figure 8: Healthy lungs (LS) vs. lungs affected by pneumonia (RS). Retrieved from: https://​www.med-ed.virginia.edu/​courses/​rad/​cxr/​pathology3chest.html >
  
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 Individuals can also have a higher risk of developing pneumonia if they have had a recent viral respiratory infection (such as a cold or flu), or if they have a chronic lung or other serious disease such as cystic fibrosis, COPD, diabetes, or sickle cell disease (Healthline,​ 2015). Diseases such as these increase risk because they make breathing difficult, block airways, and have symptoms that are similar to and can be exacerbated by pneumonia (Healthline,​ 2015). In addition, individuals with these diseases may also be prescribed immunosuppressant drugs such as inhaled corticosteroids (Healthline,​ 2015). Having a cold or flu can cause bacterial pneumonia to develop on its own, most commonly from the Streptococcus pneumoniae bacteria (Mayo Clinic, 2016). Individuals can also have a higher risk of developing pneumonia if they have had a recent viral respiratory infection (such as a cold or flu), or if they have a chronic lung or other serious disease such as cystic fibrosis, COPD, diabetes, or sickle cell disease (Healthline,​ 2015). Diseases such as these increase risk because they make breathing difficult, block airways, and have symptoms that are similar to and can be exacerbated by pneumonia (Healthline,​ 2015). In addition, individuals with these diseases may also be prescribed immunosuppressant drugs such as inhaled corticosteroids (Healthline,​ 2015). Having a cold or flu can cause bacterial pneumonia to develop on its own, most commonly from the Streptococcus pneumoniae bacteria (Mayo Clinic, 2016).
  
-<​box ​44% round right| > {{:​ICU.jpg|}} </box| Figure 9: ICU Ventilators,​ one of the methods in which an individual can contract hospital-acquired pneumonia. Retrieved from: http://​medsunhealthcare.com/​wp-content/​uploads/​2015/​11/​4.-ICU-Ventilator.jpg>​+<​box ​48% round right| > {{:​ICU.jpg|}} </box| Figure 9: ICU Ventilators,​ one of the methods in which an individual can contract hospital-acquired pneumonia. Retrieved from: http://​medsunhealthcare.com/​wp-content/​uploads/​2015/​11/​4.-ICU-Ventilator.jpg>​
  
 ====Lifestyle Risk Factors==== ====Lifestyle Risk Factors====
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-<​box ​30% round right| > {{:​intubation.png|}} </box| Figure 11: Invasive ​ventilation ​(intubation). ​ Retrieved from: https://​www.google.ca/​search?​q=oxygen+therapy&​client=safari&​rls=en&​biw=562&​bih=679&​source=lnms&​tbm=isch&​sa=X&​ved=0ahUKEwiSm-DP5YbSAhVE5SYKHd9WBsgQ_AUIBigB#​tbm=isch&​q=ventilator+in+pneumonia&​imgrc=RI46QSkVwZ6XRM:>​+<​box ​36% round center| > {{:​intubation.png|}} </box| Figure 11: Invasive ​Ventilation ​(intubation). Retrieved from: https://​www.google.ca/​search?​q=oxygen+therapy&​client=safari&​rls=en&​biw=562&​bih=679&​source=lnms&​tbm=isch&​sa=X&​ved=0ahUKEwiSm-DP5YbSAhVE5SYKHd9WBsgQ_AUIBigB#​tbm=isch&​q=ventilator+in+pneumonia&​imgrc=RI46QSkVwZ6XRM:>​
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 ======Future Global Burden====== ======Future Global Burden======
  
-As indicated earlier, ​LTRIs were the second highest global burden of disease in 2012 and this number is comprised of many cases of childhood pneumonia. ​In addition with diarrhea, the two disease have been implicated as being the cause of attendance at health services for low and middle-income families. As seen in the below figure, younger age groups (0-2 years) currently make up 81% of the youth lives lost to pneumonia. ​ Studies have found that currently, the greatest burden of disease for childhood pneumonia is in Southeast Asia and Africa due to poor hygienic conditions, malnutrition,​ and sub-optimal breast-feeding (which prevents children from acquiring passive immunity). As of now, 15 developing countries contribute to 64% of total global cases of pneumonia. Although ​this number ​is expected to decrease in the future, action is required on a global scale to reduce the prevalence of this mostly preventable illness. ​+As indicated earlier, ​LTRs were the second highest global burden of disease in 2012 and this number is comprised of many cases of childhood pneumonia. ​A large scalesystematic literature review conducted in 2013 studied ​the Global Burden ​of Childhood Pneumonia and Diarrhea. The results were divided based on global and regional burden and burden by age and number. The authors found incidence and case-related fatality ratios were higher in low and middle income families, suggesting economic status played a large role in disease determinance. As seen in the below figure, younger age groups (0-2 years) currently make up 81% of the youth lives lost to pneumonia. ​ Studies have found that currently, the greatest burden of disease for childhood pneumonia is in Southeast Asia and Africa due to poor hygienic conditions, malnutrition,​ and sub-optimal breast-feeding (which prevents children from acquiring passive immunity). As of now, 15 developing countries contribute to 64% of total global cases of pneumonia. Lastly, nearly ⅓ severe diarrhoea and pneumonia cases are vaccine-preventable suggesting the need for political and societal intervention. Although ​the burden of childhood pneumonia ​is expected to decrease in the future, largely due to increasing awareness and better healthcare facilities, action is required ​immediately ​on a global scale to actively ​reduce the prevalence of this mostly preventable illness. ​
  
- +<​box ​53% round | > {{:​walker.png|}} </box| Figure 12: Global Distribution of cases and of deaths from diarrhea and pneumonia in children aged 0-4 years. (Walker, 2013)>
-<​box ​50% round | > {{:​walker.png|}} </box| Figure 12: Global Distribution of cases and of deaths from diarrhea and pneumonia in children aged 0-4 years. (Walker, 2013)>+
  
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 ======References====== ======References======
  
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