PDF Pathology | Introduction & Overview

Pathology lecture (1) INTRODUCTION TO PATHOLOGY Pathology  The science, which deals with the study of diseases.  Bridge between basic medical sciences [anatomy, histology, physiology, biochemistry,..] and cli...

Pathology lecture (1) INTRODUCTION TO PATHOLOGY Pathology  The science, which deals with the study of diseases.  Bridge between basic medical sciences [anatomy, histology, physiology, biochemistry,..] and clinical medical sciences [medicine, surgery, obs & gyne,….].  “A State in which an individual exhibits an anatomical, physiological, or biochemical deviation from the normal” 1. Congenital & Hereditary diseases 2. Acquired diseases : Degeneration Inflammation Circulatory disturbance Tumors ❶ ❼ ❷ ❽ ❸ ❾ ❹ ❿ ❺ ❻ Pathology  The total number of cases in a population.  The new cases of certain condition within a specified period of time in certain population.  The causes of the disease ‫سبب املرض‬ Risk factors which make an individual more susceptible to a disease than others (obesity, poor ventilation, etc.). Directly responsible for a disease Congenital or Hereditary: Defective foetal development in uterus. Acquired factors (after birth): a. Exogenous (environmental) factors as Microbes b. Endogenous (internal factors) as endocrine disturbance  The process by which a disease develops: ‫طريقة حدوث املرض‬  Mechanisms and sequence of events involved in disease development  The changes induced in the cells and organs of the body and caused by disease.  Examined tissue could be: a. Biopsy: A specimen from the lesion during life b. Autopsy: A specimen from the lesion post-mortem.  Gross.  Microscopic:  Light microscope  Electron microscope Pathology The clinical effects of the pathological changes.  The patient’s complaint by his own words as ‘’pain’’.  Subjective, observed by the patient, and not measured.  A medical observation which is objective determined by a physician during a physical examination of a patient eg. (elevated blood pressure)  The expected outcome or fate of a disease; forecast of the course & termination of a disease.  The disease itself  Patient’s related factors  Effective management.  Additional pathological changes that aggravate the original disease.  May occur during or after the termination of usual course of disease.  Pathology  Involves gross and microscopic examination of surgical specimens, as well as biopsies submitted by clinicians.  The practice of surgical pathology is mandatory for: 1) Diagnosis: identify the disease. 2) Determination of treatment: medical, surgical, radiotherapy, chemotherapy. 3) Follow up: to determine its success and effectiveness of therapy.  Therapeutic surgical resection of the entire  Surgical resection of part of the lesion for lesion. diagnosis.  Punch of tissue obtained superficial lesions.  Core of tissue obtained by large-bore needles, sometimes radiologically guided.  Pathology  fluid aspiration from the lesion tissue by a fine  (as urine, ascitis,…) for cytologic smear needle for cytologic smear preparation. preparation and examination.  Scraping from the surface epithelium of a  Using a round stiff bristle brush to collect lesion. cells from all layers of the epithelium of a lesion.  Immediate specimen fixation is mandatory.  The widely used fixative is 10% formaldehyde (Formalin) buffered to a neutral pH.  Good fixation is very important in the production of satisfactory results in histopathology  Importance: 1) Fixation will preserve the morphology. 2) Prevent decomposition and autolysis. 3) Minimize microbial/fungal growth. 4) Minimize the loss of molecular components.  Recognition of the anatomic landmarks.  Localization the lesion.  Cutting proper Sections needed for diagnosis (sampling).  Gross changes of organs can be detected by radiology.  Pathology  All tissue samples cut grossly from the specimen should be processed and sectioned on glass slides.  Sections should be stained by Hematoxylin and Eosin (H&E) for microscopic examination.  Other special stains could be used.  Immunohistochemistry Specific monoclonal antibodies help to identify cell products or surface markers.  Rapid microscopic examination of fresh tissue is done for intraoperative consultation which is needed for important decisions during operation.  Frozen section technique preparing histologic slides.  Imprint cytologic slides