RRS | Lecture 22
RRS | Lecture 22
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Quiz Questions (10 questions)
1. The diagnosis of pulmonary tuberculosis involves monitoring the effectiveness of treatment through sputum smear examination, which detects the presence of acid-fast bacilli and helps in assessing bacterial load.
2. The Mantoux test, or tuberculin skin test, is utilized to screen for latent tuberculosis infection by introducing purified protein derivative (PPD) under the skin and measuring the resulting induration.
3. The diagnosis of drug-resistant tuberculosis can be established using liquid culture methods that allow for the growth of Mycobacterium tuberculosis and testing its sensitivity to various antibiotics.
4. The BCG vaccine is administered for the prevention of tuberculosis, primarily to protect against severe forms of TB in children, by stimulating an immune response against Mycobacterium tuberculosis.
5. Patients with latent tuberculosis infection exhibit no symptoms of the disease, though they may have a positive skin test, indicating prior exposure to Mycobacterium tuberculosis.
6. The interferon-gamma release assay (IGRA) is a blood test intended for the detection of latent tuberculosis infection by measuring the immune response to specific TB antigens.
7. For the diagnosis of pulmonary tuberculosis, it is recommended to collect three early morning sputum specimens, as these samples are more likely to contain detectable levels of Mycobacterium tuberculosis.
8. The difficulty in diagnosing tuberculosis stems from the fact that the disease may take years to become active, during which symptoms can be subtle or non-specific, complicating clinical detection.
9. In young children with suspected pulmonary tuberculosis, gastric aspirate is often used as the best clinical specimen for diagnosis, as they may not be able to produce sputum effectively.
10. The QuantiFERON-TB test serves as a gold standard test for detecting Mycobacterium tuberculosis by measuring the release of interferon-gamma in response to specific TB antigens in a blood sample.
Previous Exam Questions (20 questions)
1. The disseminated disease caused by hematogenous spread of Mycobacterium tuberculosis that results in lungs studded with millet-like seeds is called Milliary T.B. This form, known as miliary tuberculosis, is characterized by numerous small nodules resembling millet seeds throughout the lungs, which result from the widespread dissemination of the bacteria through the bloodstream.
2. The bacterial structure that helps Mycobacterium tuberculosis survive within macrophages is Sulpholipids. These molecules are part of the cell envelope and play a crucial role in inhibiting the fusion of the phagosome containing the bacterium with lysosomes, thus allowing the bacteria to survive and replicate within the macrophage.
3. The virulence factor that allows Mycobacterium tuberculosis to inhibit phagosome-lysosome fusion to survive intracellularly is Sulfatides. Sulfatides are glycolipids found in the cell wall of M. tuberculosis, which interfere with normal phagosome maturation and prevent the fusion with lysosomes, aiding in the pathogen's survival within host cells.
4. The defining characteristic measured in the Mantoux test is Cellular infiltration. This test involves the intradermal injection of purified protein derivative (PPD) and measures the delayed-type hypersensitivity reaction, which is a result of cellular infiltration by T-cells and macrophages at the site of injection, indicating prior sensitization to tuberculosis antigens.
5. The diagnostic test intended for latent tuberculosis infection is the Interferon-gamma release assay (IGRA). This test measures the immune response to specific antigens associated with Mycobacterium tuberculosis, assessing the production of interferon-gamma by T-cells when exposed to these antigens, indicating a latent infection.
6. The primary mode of transmission for Mycobacterium tuberculosis is Respiratory droplets. This bacterium is primarily spread when an infected person coughs, sneezes, or talks, releasing tiny droplets containing the bacteria into the air, which can be inhaled by others, leading to infection.
7. A distinguishing feature of Mycobacterium tuberculosis is that it is Acid-fast rods. This characteristic is due to the high lipid content in the cell wall, particularly mycolic acids, which make the bacteria resistant to decolorization by acids during staining, a hallmark of acid-fast bacteria.
8. The type of immune response primarily involved in the pathogenesis of tuberculosis is Cell-mediated immunity. This response is critical in controlling and limiting the infection, involving T-cells that recognize infected macrophages and release cytokines to activate more macrophages to kill the bacteria.
9. The component in the cell wall of Mycobacterium tuberculosis that contributes to its virulence and resistance to desiccation is Mycolic acids. These long fatty acids form a waxy layer that protects the bacteria from dehydration and chemical damage, and also plays a role in the pathogen's resistance to host immune responses.
10. The test that measures the immune response to Mycobacterium tuberculosis antigens is the PPD skin test (Mantoux test). This involves injecting a small amount of tuberculin into the skin and examining the site for induration, which is a measure of the body's immune response to the antigens, indicating exposure or infection.
11. The function of the cord factor in Mycobacterium tuberculosis is to inhibit leukocyte migration. Cord factor, a trehalose dimycolate found in the cell wall, is a virulence factor that helps in forming serpentine cords and is involved in the pathogenesis by hindering the migration of leukocytes, thus impairing the host's immune response.
12. The culture medium typically used to grow Mycobacterium tuberculosis is Lowenstein-Jensen medium. This egg-based medium provides the nutrients necessary for Mycobacterium tuberculosis to grow, as it is a slow-growing bacterium that requires several weeks for visible colony formation.
13. 1) The test used to diagnose latent pulmonary tuberculosis is the Mantoux test or the TB Gold test, which measures the immune response to Mycobacterium tuberculosis through a skin reaction or the production of interferon-gamma, respectively. These tests are crucial for identifying individuals who are infected but not yet symptomatic, allowing for early intervention and prevention of disease spread.
14. 2) Mycobacteria are acid-fast bacteria because of the presence of mycolic acid in the bacterial cell wall, which gives the bacteria their characteristic resistance to decolorization by acids during staining. This property is essential for the identification of Mycobacterium species in clinical settings using techniques such as Ziehl-Neelsen staining.
15. 3) For a two-year-old child with suspected TB, the best clinical specimen for pulmonary TB diagnosis is a gastric aspirate, which involves collecting stomach contents after the child has swallowed mucus coughed up from the lungs. This method is particularly useful in young children who are unable to expectorate sputum effectively.
16. 4) The type of immune response primarily involved in the pathogenesis of tuberculosis is cell-mediated immunity, which involves the activation of T-cells that recognize and respond to Mycobacterium tuberculosis antigens. This response is crucial for containing the infection but can also lead to tissue damage if not properly regulated.
17. 5) The standard culture medium used for isolating Mycobacterium tuberculosis is Lowenstein-Jensen medium, which supports the slow growth of the bacteria and is used extensively in laboratories to confirm TB infections. This medium contains nutrients and inhibitors that prevent the growth of contaminating organisms.
18. 6) The typical transmission route for Mycobacterium tuberculosis is through respiratory droplets, which are expelled when an infected person coughs, sneezes, or speaks. These droplets can be inhaled by others, leading to the spread of the infection, particularly in crowded or poorly ventilated environments.
19. 7) The cord factor in Mycobacterium tuberculosis inhibits leukocyte migration and contributes to its virulence by preventing the fusion of phagosomes with lysosomes in macrophages. This allows the bacteria to survive and multiply within immune cells, evading the host's defense mechanisms.
20. 8) The test used to diagnose latent tuberculosis infection that measures interferon-gamma production is called the Interferon-gamma release assay (IGRA). This blood test evaluates the immune system's response to specific TB antigens, providing a more specific and less invasive alternative to the traditional skin test.
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**Understanding Tuberculosis: A Comprehensive Study Guide** **Introduction to Tuberculosis** **Tuberculosis (TB)** is primarily a disease affecting the lungs, known as **Pulmonary TB**, though it can also spread to other parts of the body, referred to as **Extra-pulmonary TB** in about one-third o...
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What is the primary method of transmission for Mycobacterium...
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