PATHOLOGY UPDATED COMPLETE NOTES 2023

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Pathology Syllabus Notes Pathology Syllabus Notes 1 I. General Pathology 1 II. Systemic Pathology 60 Cardiovascular pathology 60 Pulmonary pathology 82 Gastrointestinal pathology 95 Hepatic and... Pancreatic Pathologies 108 Renal Pathology 116 Haematologic & Bone Marrow Diseases 121 Endocrinology Pathology 135 Pathologies of the Central Nervous System 146 Pathologies of infectious diseases 152 I. General Pathology 1. General and Special Pathology objectives. Basic terminology, purpose, tasks, methods. General and Special Pathology objectives Pathology quite literally comes from ‘Pathos’ (suffering) ‘Logos’ (study), i.e. the study of suffering. Pathology can be seen as having two main objectives: - Etiology - causes of disease (why a disease develops) - Pathogenesis - development of disease in the body (how a disease develops) General pathology is common changes in all tissues, for instance, all tissues can undergo inflammation, cancer and aging, meanwhile, special pathology looks to examine the etiology and pathogenesis of particular specialized organs, e.g. pneumonia, breast cancer. It can therefore be said that pathology provides the scientific foundation for the practice of medicine. Basic terminology, purpose, tasks, methods Here we will consider some core terms and their meaning in the context of Pathology: - Disease - ‘Expression of discomfort due to structural or functional abnormality’ - Disease can be: - Inflammatory Pathology Notes - Feb 2019 navidmtomlinson@gmail.com - Acute/Chronic - Congenital/Acquired - Genetic/environmental - Mild/Moderate/Severe - Has four aspects - Etiology (causal agent) - Pathogenesis (mechanism of change) - Morphology (structural change) - Clinical expression - Death - Clinical Death (reversible cessation of blood circulation and breathing) - Biological Death (irreversible) The primary methods of Pathology are: - Autopsy - Clarifies cause of death and helps improve future treatment - Two types - Hospital - for patients that died of natural causes - Or Forensic - legal case concerned - Includes External examination, Dissection and Pathology protocol - Biopsy (known as Necroscopy in dead tissue) - Histological - Investigation of tissue, methods include - Surgery - Endoscopy - Large needle biopsy - Cytological - Investigation of isolated cells - May be body fluids, fine needle biopsy of vaginal smears Other methods in Pathology include - Electron microscopy - Immunofluorescence - Immunohistochemistry - Molecular pathological methods (e.g. PCR) and others. 2. Cellular injury; common causes and mechanisms Cells exist in homeostasis . Where they are subject to stress they attempt to adapt . Where they are unable to adapt they become ‘Injured cells’ . Common methods of adaptation include hypertrophy (increase in cellular size), Hyperplasia (increase in cellular number), atrophy (shrinkage of cell by loss of substance) and metaplasia (replacing of cells by different cellular types, think tough calluses of skin). 2/166 Pathology Notes - Feb 2019 navidmtomlinson@gmail.com The most common cause of cellular injury is Hypoxia , or oxygen deficiency, as it prevents aerobic oxidative respiration, and the conversion of carbohydrates into ATP. Hypoxia can often be caused by Ischemia , lack of blood supply to an affected area, but also as a result of pneumonia (lack of oxygen in blood), anemia (reduction of oxygen carrying capacity of blood) and CO poisoning . Other important causes include: - Chemical agents - Such as high glucose, salt, oxygen, CO or other toxic agents - Infectious agents - Immunologic reactions - Physical agents - Nutritional imbalances - Genetic defects - Aging These problems cause the cell to become nonfunctional, this dysfunction leads to cellular injury, we’ll now consider the mechanism of cell injury . The following mechanisms of cell injury are the most common, and usually combined: - Depletion of ATP (failure of energy --- Necrosis) - Causes; Influx of Sodium and Calcium ions and osmotic swelling due to failure of ATP dependent ion pumps - ATP depleted cells being anaerobic metabolism to derive energy from glycogen (Glycolysis) - Results in decrease of pH , creating acidic environment and damaging enzymes. - Causes clumping of nuclear chromatin , pyknosis, leading to cellular necrosis. - Damage to Mitochondria (leads to ATP depletion, high Ca2+ and ROS common causes) - Influx of calcium (activates enzymes with damaging cellular effects) - Accumulation of Oxygen-Derived free radicals (Damages membrane and DNA) - Defects in membrane permeability - Damage to DNA and proteins - Disruption to cell membrane 3. Reversible cell injury due to compromised ionic transfer (cellular swelling): granular degeneration, vacuolar degeneration, hydropic change Cellular injury can be reversible or irreversible . Multiple morphological changes can be shown in reversible damage: - Cellular swelling (result of defective energy-dependent ion pumps leading to poor fluid homeostasis). 3 [Show More]

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