RESPIRATORY - Tuberculosis - Midterm Notes PDF

Here is an organized summary of Tuberculosis (TB) from the notes provided. Each concept is categorized according to the following criteria: most likely cause, pathophysiology, disease transmission, and risk factors. Tuberculosis (TB) Tuberculosis (TB) is a highly contagious infec:ous disease caused...

Here is an organized summary of Tuberculosis (TB) from the notes provided. Each concept is categorized according to the following criteria: most likely cause, pathophysiology, disease transmission, and risk factors. Tuberculosis (TB) Tuberculosis (TB) is a highly contagious infec:ous disease caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs but can spread to other organs (extrapulmonary TB) in certain cases【106:0†Module 4 Respiratory Slides】. 1. Most Likely Cause Cause: o Mycobacterium tuberculosis is the primary causaLve agent of tuberculosis【 106:0†Module 4 Respiratory Slides】. o It is an acid-fast bacillus that is resistant to destrucLon by immune cells like macrophages due to its thick, waxy cell wall【106:0†Module 4 Respiratory Slides 】. 2. Pathophysiology The pathophysiology of TB is a complex process involving immune system interacLons and granuloma formaLon. The key steps are as follows: 1. Inhala:on and Lung Infec:on: o InhalaLon of airborne droplets containing Mycobacterium tuberculosis leads to the deposiLon of the bacteria in the upper lobes of the lungs【106:0†Module 4 Respiratory Slides】. o The bacteria migrate to the lymph nodes where they are phagocytosed by alveolar macrophages and neutrophils【106:0†Module 4 Respiratory Slides】. 2. Survival Inside Macrophages: o Mycobacterium tuberculosis can survive within macrophages by inhibiLng lysosomal fusion. It releases factors that allow it to escape destrucLon, resulLng in persistent intracellular infecLon【106:0†Module 4 Respiratory Slides】. 3. Granuloma Forma:on: o The immune system responds by forming a granuloma (tubercle) to "wall off" the bacteria, aQempLng to isolate it from the rest of the body. o Casea:on necrosis occurs within the granuloma, where Lssue becomes necroLc and cheese-like (caseous)【106:0†Module 4 Respiratory Slides】. o Collagen is deposited around the granuloma, effecLvely "sealing" the bacteria inside. This process takes about 10 days【106:0†Module 4 Respiratory Slides】. 4. Latent TB Infec:on (LTBI): o In immunocompetent individuals, the infecLon may remain dormant, leading to latent tuberculosis infec:on (LTBI), where bacteria are contained but not killed. LTBI may last for the person's lifeLme【106:0†Module 4 Respiratory Slides】. 5. Ac:ve Tuberculosis:  o If the immune system weakens (due to HIV infec:on, malnutri:on, or aging), the granuloma may break down, releasing the bacteria. o This can result in the progression to ac:ve TB disease, where the bacteria spread throughout the lungs and other organs【106:0†Module 4 Respiratory Slides】. 3. Disease Transmission Transmission: o Tuberculosis is spread via airborne droplets produced when an infected person coughs, sneezes, speaks, or sings【106:0†Module 4 Respiratory Slides】. o The bacteria remain suspended in the air for extended periods, making it highly transmissible, especially in crowded environments【106:0†Module 4 Respiratory Slides】. o Close, prolonged exposure to an infected individual significantly increases the risk of transmission【106:0†Module 4 Respiratory Slides】. 4. Risk Factors The risk factors for developing tuberculosis can be classified as environmental, individual, and immunosuppressive. Environmental Risk Factors Crowded Living Condi:ons: Individuals living in overcrowded housing, prisons, or shelters are at a higher risk due to limited airflow and prolonged exposure to infected individuals【106:0†Module 4 Respiratory Slides】. Homelessness: People experiencing homelessness are at higher risk because of crowded shelters and limited access to healthcare【106:0†Module 4 Respiratory Slides】. Immigra:on from Endemic Areas: EmigraLon from high-prevalence regions (like Southeast Asia, Africa, and the Western Pacific) increases the risk of TB【 106:0†Module 4 Respiratory Slides】. Individual Risk Factors Age: The highest incidence of acLve TB occurs in the 25-34 age group and in those aged 65 years or older【106:0†Module 4 Respiratory Slides】. Substance Use: Drug and alcohol misuse compromise the immune system, increasing the risk of progression from latent TB to acLve TB【106:0†Module 4 Respiratory Slides 】. Indigenous Popula:ons: Indigenous popula:ons (e.g., Inuit, First NaLons) experience disproporLonately higher rates of TB. For example, the TB incidence is 135 per 100,000 in Inuit populaLons, significantly higher than in non-Indigenous populaLons【 106:0†Module 4 Respiratory Slides】. Immunosuppressive Risk Factors HIV Infec:on: HIV co-infecLon is a major risk factor for developing acLve TB from latent TB infecLon due to immunosuppression【106:0†Module 4 Respiratory Slides】. Chronic Illness: CondiLons like chronic kidney disease (CKD), diabetes mellitus, or cancer increase the risk of TB reacLvaLon【106:0†Module 4 Respiratory Slides】.  Immunosuppressive Therapy: Individuals on cor:costeroids, chemotherapy, or an:- TNF agents (for autoimmune diseases) have an increased risk of reacLvaLng latent TB【 106:0†Module 4 Respiratory Slides】. Poor Access to Healthcare: Lack of access to proper screening, treatment, and follow- up care increases the likelihood of latent TB progressing to acLve TB【106:0†Module 4 Respiratory Slides】. Summary Table Criteria Tuberculosis (TB) Mycobacterium tuberculosis, an acid-fast bacillus【106:0†Module 4 Cause Respiratory Slides】. 1. Inhala:on of droplets → 2. Phagocytosis by macrophages → 3. Granuloma Pathophysiology forma:on → 4. Latent TB (LTBI) or Ac:ve TB if the immune system fails【 106:0†Module 4 Respiratory Slides】. Airborne droplets from infected individuals coughing, sneezing, or speaking Transmission 【106:0†Module 4 Respiratory Slides】. Environmental: Crowded housing, homelessness, immigraLon from endemic areas. Individual: Substance use, age (25-34, 65+), Indigenous populaLons. Risk Factors Immunosuppressive: HIV, chronic illness, cancer, corLcosteroids, immunosuppressive therapy【106:0†Module 4 Respiratory Slides】. If you'd like addiLonal clarificaLon on any of these points or further details on a specific concept, feel free to ask!