Title Excellence Pathology.pdf ✅

Excellence for MRCS OSCE By Dr. Rifat & Dr. Hasnat 3 What are the fates of granulation tissue? ê Remodeling ê Scar formation (after 2-3 weeks) What is pus? Pus is the product of acute inflammation composed of cellular and fluid, exudative phases. OR Pus is a purulent inflammatory exudate and consists of: ê Profuse healthy leucocytes, mostly neutrophils ê Protein-rich fluid exudate and fibrin ê Necrotic cells ê Tissue debris ê Organisms What are the constituents of pus? ê Neutrophil ê Dead organism ê Tissue debris ê Liquified tissue How to know causative organism of abscess clinically without any test? ê Yellowish - Staphylococcus aureus ê Greenish - Pseudomonas ê Sulphur granules – Actinomyces Why does the pus formed by Pseudomonas appear green? White blood cells (mainly neutrophil) produce a green antibacterial protein called myeloperoxidase which contains heme compound; this is responsible for greenish pus. Pathogenesis of pus formation? Microbial invasions → acute inflammation with vascular congestion and exudation of fluids with infiltration of PMNs. Types of pus? ê Purulent exudate: This is the most common type of pus, produced by bacterial infections and typically yellow or green in color. ê Seropurulent exudate: This type of pus contains both blood and pus and is typically produced by infections in the deeper tissues or organ. ê Sanguineous exudate: This is a pink or reddish fluid that contains mostly blood and is often seen in Wounds or abscesses Caused by injury or trauma. ê Fibrinous exudate: This type of pus is thick and sticky and is produced by the body's response to inflammation or injury. ê Pyogenic exudate: This is a term used to describe any type of pus produced by a bacterial infection. How do neutrophils migrate to the site of inflammation? ê Neutrophil has a circulatory life span of 12 – 18 hours. ê Margination and rolling along the vessel wall ê Firm adhesion to the endothelium ê Transmigration between endothelial cells ê Migration in interstitial tissues toward a chemoattractant stimulus Blood tests to identify the inflammation? ê ESR, CRP ê White blood cells count ê Procalcitonin
Excellence for MRCS OSCE By Dr. Rifat & Dr. Hasnat 4 The multistep process of leukocyte migration through blood vessels. The leukocytes first roll, then become activated and adhere to endothelium, then transmigrate across the endothelium, pierce the basement membrane, and migrate toward chemoattractant emanating from the source of injury. Different molecules play predominant roles in different steps of this process: selectins in rolling; chemokines (usually displayed bound to proteoglycans) in activating the neutrophils to increase avidity of integrins; integrins in firm adhesion; and CD31 (PECAM-1) in transmigration. ICAM-1, Intercellular adhesion molecule 1; PECAM-1 (CD31), platelet endothelial cell adhesion molecule-1. Which cell will you find abundantly in the pelvic collection? Neutrophil What is the appearance of neutrophil in PBF? Structure of neutrophil? Neutrophils have a segmented nucleus with a cytoplasm enriched with granules & secretory vesicles. Life span of neutrophils? 12-18 hrs. (Circulating half-life of 6-8h). Source of neutrophils? ê Neutrophils generated in bone marrow with increased production during infection (10-fold). ê Initial neutrophil recruitment [release from bone marrow] due to inflammatory mediators (such as cytokines, leukotrienes, and histamine) released by tissue-resident leukocytes that encounter pathogens. ê The high number of circulating neutrophils is the result of regulated release of new neutrophils from bone marrow as well as from marginated pools (Marginated pools, such as the spleen and lung). What are the contents of neutrophil granules? ê Primary granules: toxic mediators & bactericidal agents (proteolytic enzymes, cathepsin G, myeloperoxidase, elastase) ê Secondary granules (specific granules): toxic oxygen compounds, lysozyme, leucocidins & lactoferrin. ê Tertiary (Gelatinase) Granules: Gelatinase, Matrix metalloproteinases (MMPs) Organisms causing abscess? / What are the causes of abscess? ê Bacterial: Staphylococcus aureus, Streptococcus pyogenes ê Non-bacterial: Fungal, viral, parasitic Fig: Abscess in light microscope with PMNC infiltrate