W1 Introduction to Pathology PDF

DR ZAKARIA ELTAHIR Introduction to Pathology… Well come to your pathology module  What is “pathology” means? Pathology is the “Scientific study of disease” “The molecular, cellular, tissue, organ or system response to injurious agents"  Pathology serves as a "bridge" or...

DR ZAKARIA ELTAHIR Introduction to Pathology… Well come to your pathology module  What is “pathology” means? Pathology is the “Scientific study of disease” “The molecular, cellular, tissue, organ or system response to injurious agents"  Pathology serves as a "bridge" or "link" between the preclinical science (anatomy, physiology, ……etc.) and the courses in clinical medicine RCPath Defines pathology as: “The science behind cure”  The study of patterns, causes, mechanisms and effects of illness The interpretation of symptoms that are important to know the range of abnormalities possible in an organ/system Bases of differential diagnosis (>70%) Histopathology Haematology Clinical chemistry Immunology Microbiology Genetics Haematology Clinical chemistry Immunology Microbiology Genetics Haematology Clinical chemistry Immunology Microbiology Genetics CELLULAR PATHOLOGY General Pathology Common changes in all tissues. e.g.. Inflammation, cancer, ageing, edema, hemorrhage ….etc. Systemic Pathology Pathologic mechanisms in relation to various organ systems e.g. CVS, CNS, GIT…..etc. 1. Human pathology (1) Autopsy (2) Biopsy (3) Cytology: smear, fine needle aspiration 2. Experimental pathology (1) Animal experiment (animal model) (2) Tissue and cell culture  Biopsy: Removal and examination of tissue obtained from a living body  Autopsy: Gross examination of the human cadaver by systematic dissection to identify cause of death  Necropsy: Synonymous to autopsy in animal cadaver Forensic pathology: The branch of medicine dealing with the application of medical knowledge to establish facts in civil or criminal legal cases, such as an investigation into the cause and time of a suspicious death. Also known as Forensic medicine  Definition  Epidemiology – Where & When  Etiology – What is the cause?  Pathogenesis - Evolution of disease  Morphology - Structural Changes  Functional consequences  Management  Prognosis  Prevention  A disorder of structure or function in a human, animal, or plant, especially one that produces specific symptoms or that affects a specific location and is not simply a direct result of physical injury  (A)Developmental – genetic, congenital  (B)Acquired: - COVID19, lung cancer (1)Inflammatory – Trauma, infections, immune, etc (2)Neoplastic – tumors cancers (3)Degenerative – ageing (4)Metabolic: glutamine (5)Iatrogenic: Drug induced Figure 1. Map showing geographic variation in MS prevalence and in data confidence scoresa by country: (a) MS prevalence per 100,000 population by country shown in shades of orange and red as per the key. Countries without prevalence data are shown in grey. (b) Confidence score assigned to each country based on the prevalence data sources provided. Scores of very low, low, moderate or high are shown in shades of orange and red as per the key. Countries without prevalence data or with data but no source information provided are shown in grey. A Country confidence scores were assigned using four variables: (1) size of the population covered by data source, from 0 if unknown to 5 if covering the whole country; (2) year of data collection by source, from 0 if prior to 2009 to 5 if in 2017–2019; (3) type of data source, from 0 if unknown to 5 if peer-reviewed journal publication; (4) additional points were given for meeting certain methodological criteria: using the 2017 McDonald Criteria, performing a validation step or using multiple consistent data sources for the estimate. Confidence ratings were assigned based on the total scores using the following thresholds: ⩽5 = very low, 6–10 = low, 11–15 = moderate, ⩾16 = high. Journal of Multiple Sclerosis, Volume: 26 issue: 14, page(s): 1816-1821 - First Published November 11, 2020 Knowledge of remains the backbone of:  Disease diagnosis  Understanding the nature of disease  Treatment of disease An etiologic agent : Is the factor (bacterium, virus, etc.) responsible for lesions or a disease state Predisposing Cause of Disease: Factors which make an individual more susceptible to a disease (Smoking, damp weather, poor ventilation, etc.) Exciting Causes of Disease: Factors which are directly responsible for a disease (hypoxia, chemical agents, virus, bacteria …. etc.)  Disease Disease Disease Disease Disease Several etiologic One etiologic agent One etiologic agent agents one disease several diseases - one disease, (cancer) as smoking as Malaria. The molecular, physiological and cellular mechanisms that occur after the first injury and which lead to the expression of a disease Understanding pathogenesis is important in choosing, or developing, an appropriate therapy Only one option available: ADAPTING SUSTAINING REVERSIBLE INJURY SUFFERING IRREVERSIBLE INJURY AND DYING Clinical symptoms: are the patient’s complain usually by its own words e.g; pain, headache Clinical signs/Obs: are seen only in the living individual as organomegaly  Morphology remains at the heart of diagnostic pathology Morphologic change - Characteristic of the disease - Diagnostic of the etiologic process Functional derangements - Characteristic changes of organ function etc.. (1)Gross appearance:  size, shape  weight  color  consistency  surface  edge, section FISH ERBB2  (2)Microscopic examination Usually in tissue thin sections fixed in formalin then stained by HE (hematoxylin and eosin) to be examined by light microscope for Histologic and cytologic changes Hemangioma PAS→BM 1. Ag-Ab specific reaction 2. Applications : in diagnosis of tumor histogenesis Macrophages Leiomyosarcoma Actin (+) CD68 (+) MS (3)Gross appearance via EM By using electron microscope) Filtering membrane SEM (scanning electron microscope) Podocyte  (4)Flow Cytometry (FCM) In neoplastic diseases Can determine: 1- If there is one kind of cells→ quantitative assessment 2. DNA ploidy analysis (amount of DNA)  (5)Image Analysis it can determine circumference area; volume & morphology  (5)Image Analysis 1. Polymerase chain reaction (PCR) 2. DNA sequencing Expected outcome of the disease, It is the clinician's estimate of the severity and possible result of a disease Excpression of PTEN assessment in reistense to therapy THE END