Week 8 - Intro to Pathology Slides.pdf

Introduction to Pathology Dr Muhammed Sohail Reader in histopathology and Consultant Cellular Pathologist [email protected] 1 Intended Learning Outcomes • To learn about to various sub -specialities in pathology and its relevance to dentistry. • To learn about c lassification of diseases....

Introduction to Pathology Dr Muhammed Sohail Reader in histopathology and Consultant Cellular Pathologist [email protected] 1 Intended Learning Outcomes • To learn about to various sub -specialities in pathology and its relevance to dentistry. • To learn about c lassification of diseases. 2 Introduction to Pathology Definition and Terminology Overview of Topics 3 11 November 2021 What is Pathology? The study (logos) of diseases (pathos) Structural and functional changes of cells, tissues, and organs that underlie disease 4 11 November 2021 What is Pathology? Aetiology: cause Pathogenesis: mechanisms Morphological changes: cells, tissues Clinical significance: altered function Outcome Signs, symptoms, course and prognosis of a disease 5 11 November 2021 Pathology General Pathology Systemic Pathology 6 11 November 2021 General Pathology Mechanisms and characteristics of disease processes e.g. inflammation (acute and chronic), immune responses, necrosis, apoptosis, healing, cancer 7 11 November 2021 Systemic Pathology Inflammation: gingivostomatitis (HSV) swelling, redness Immune disorder: rheumatoid arthritis joints, functional defects Cancer: squamous cell carcinoma mass, ulceration, bleeding 8 11 November 2021 Sub - specialities of Pathology • Cellular Pathology • Histopathology • Cytopathology • Microbiology and infectious diseases • Hematopathology and blood transfusion • Chemical pathology • Immunology 9 11 November 2021 Classification of Diseases Why do we classify diseases? 10 11 November 2021 Classification of Diseases Why do we classify diseases? 1 11 November 2021 Classification of Diseases • We classify diseases for various reasons • Helps in communication with other health professionals • Easy to memorise common characteristics of diseases as a group • Helps in management of diseases. 2 11 November 2021 Classification of Diseases • Diseases can be classified on various grounds, e.g., • Primary v/s Secondary • Acute v/s Chronic • Congenital v/s Acquired • Infectious v/s non -infectious 3 11 November 2021 Classification of Diseases • Congenital • Genetic • Non -genetic • Acquired • Inflammatory disorders • Disordered immunity • Haemodynamic disorders • Trau m ati c / acci d e ntal • Metabolic and nutritional disorders • Degenerative disorders • Growth disorders 4 11 November 2021 Classification of Diseases Congenital Diseases • Initiated before or during birth, may be due to: • Genetic defect • Inherited from the parents - cystic fibrosis • Genetic mutation before birth - Trisomy 21 • Non genetic defect • e.g. cardiac and other abnormalities secondary to maternal Rubella during pregnancy. 5 11 November 2021 Congenital genetic disorder Downs syndrome 6 11 November 2021 Robbins and Cotran Pathologic Basis of Disease, 9th Edition Classification of Diseases Inflammatory disorders • Physiological response of vascularised living tissue to injury. • Injurious agent may be: • Physical - trauma • Chemical - poison, acids, drugs etc • Biological - bacteria, viruses, fungi etc. • Usually named from the organ affected followed by the suffix 'itis' e.g. Appendicitis, Gingivostomatitis, Tonsillitis. • Characterised by redness, swelling, pain, increased temperature and loss of function. 7 11 November 2021 8 11 November 2021 Gingivostomatitis Classification of Diseases Infectious diseases • Can be further classified on the basis of infective agent into: • Bacterial • Viral • Fungal • Rickettsial etc 9 11 November 2021 Vi r a l I n c l u s i o n s Classification of Diseases Infectious diseases - Viral Gingivostomatitis (Herpes Simplex 1) Classification of Diseases Disordered Immunity • Immunity is a defence mechanism against foreign/infectious agents. It consist of: • Cells • B lymphocytes • T Lymphocytes • NK cells • Antibodies • IgM, IgG, IgA, IgE • Chemical mediators • E.g. interlukins 11 11 N o v e m b e r 2 0 2 1 Interleukin 2 Cells of the Immune System and Chemical Mediators T Lymphocytes B Lymphocytes Major Histocompatibility antigens T cell receptor Classification of Diseases Disordered Immunity • Disorders of immunity can be classified as: • Hypersensitivity reactions e.g. Bronchial asthma • Autoimmune diseases e.g. SLE • Immunologic deficiency syndromes e.g. HIV 14 11 November 2021 Classification of Diseases Haemodynamic disorders • Normal flow of blood is essential for tissues and organs. • Reduced blood flow - ischaemia may result from thrombosis or embolism • If sustained for long time may result in cell death/necrosis called infarction e.g. myocardial infarction. 15 11 November 2021 c Classification of Diseases Haemodynamic disorders • Normal flow of blood is essential for tissues and organs. • Reduced blood flow - ischaemia may result from thrombosis or embolism • If sustained for long time may result in cell death/necrosis called infarction e.g. myocardial infarction. 1 11 November 2021 2 11 November 2021 Normal blood vessels Narrowed or obliterated blood vessels 3 11 November 2021 Myocardium (heart muscle) Infarction is death of tissue (necrosis) due to ischaemia Normal myocardium Cardiac muscle 4 11 November 2021 Fibrosis Classification of Diseases Metabolic disorders • All metabolic processes in the body require different enzymes and hormones. Deficiency of any enzyme or hormone may result in metabolic disorders. These can be further classified into: • Inborn errors of metabolism e.g. • Phenylketonuria (hydroxylase deficiency) • Gaucher's disease (Glucocerebrosidase deficiency) • Acquired metabolic disorders e.g. • Diabetes mellitus - relative/absolute deficiency of insulin • Gout - high blood uric acid level 5 11 November 2021 6 11 November 2021 Robbins and Cotran Pathologic Basis of Disease, 9th Edition Classification of Diseases Degenerative disorders • These are characterised by a loss of the specialised structure and function of a tissue e.g. osteoarthritis. 7 11 November 2021 Robbins and Cotran Pathologic Basis of Disease, 9th Edition Classification of Diseases Growth disorders • Characterised by abnormal growth including adaptation to changing circumstances. • Hypertrophy e.g. left ventricular hypertrophy • Hyperplasia e.g. BPH • Atrophy e.g. adreno -cortical atrophy • Metaplasia e.g. squamous metaplasia • Dysplasia e.g. CIN • Neoplasia e.g. Adenoma, carcinoma, sarcoma 8 11 November 2021 9 11 November 2021 Classification of Diseases Neoplastic disorders • Neoplasm literally means new growth • In medical term it means uncontrolled cell growth • These can be further classified based on their behaviour into: • Benign • Malignant • All tumours have the suffix ' oma ' • Malignant neoplasms are also commonly called cancer 10 11 November 2021 TSG - “brake pedal” Oncogene - “accelerator” Cancer Development Classification of Diseases Neoplastic disorders - Classification • Benign Tu m o u rs : • Epithelial: Adenoma, Papilloma • Mesenchymal tumours : Fibroma, lipoma, chondroma, osteoma etc • Mixed: Pleomorphic adenoma of salivary gland • Malignant tumours : • Epithelial: Carcinoma • Mesenchymal: sarcoma • Mixed: Carcinosarcoma 13 11 November 2021 Follicular Adenoma of thyroid Squamous papilloma Tr a n s i t i o n a l c e l l papilloma Adenocarcinoma Squamous cell carcinoma Tr a n s i t i o n a l c e l l c a r c i n o m a 16 11 November 2021 Leukoplakia (benign, but can become malignant ) Oral Cancer (malignant) 17 11 November 2021 Oral Cancer 18 11 November 2021 Oral Cancer Squamous Cell Carcinoma Summary • Pathology is study of diseases and can be classified as general and systemic pathology. • Sub -specialities include cellular pathology, hematopathology, microbiology, immunology and chemical pathology. • General pathology deals with disease process like inflammation, immunological, metabolic, genetic, degenerative and neoplastic disorders. • Diseases can be classified according to the underlying mechanism of disease and this can not only help in communication with other health professionals but also help in management of diseases and remembering common features of diseases in a group. 19 11 November 2021