Introduction to Pathology PDF

Introduction to Pathology MRS. KATHRYN SATCHELL B.SC. M.SC. -UWI FMSTRC -SECTION OF PHYSICAL THERAPY Outline Introduction to Pathology Origins Clinical Pathology Pathogenesis Pathophysiology Pathologists Disease Health Illness Terminologies in Pathology Characteristic Features of Disease Etiology Pa...

Introduction to Pathology MRS. KATHRYN SATCHELL B.SC. M.SC. -UWI FMSTRC -SECTION OF PHYSICAL THERAPY Outline Introduction to Pathology Origins Clinical Pathology Pathogenesis Pathophysiology Pathologists Disease Health Illness Terminologies in Pathology Characteristic Features of Disease Etiology Pathogenesis Manifestation Outcome Classification of Disease Epidemiology of Disease Investigating Disease Health Promotion & Disease Prevention Textbook Resources After successful completion of this component of the Learning Outcomes course, the student should be able to: Define the common terms related to the study of diseases and their causes. Describe methods and instruments used in the examination of tissues. What does Pathology mean to you? Pathology – Origins  The word ‘Pathology’ is derived from two Greek words—pathos meaning suffering, and logos meaning study.  Pathology is, thus, scientific study of structure and function of the body in disease; or in other words, pathology consists of the abnormalities that occur in normal anatomy (including histology) and physiology owing to disease. Clinical Pathology  In medicine refers to pathology applied to the solution of clinical problems, especially the use of laboratory methods in clinical diagnosis. Pathology  Defined as the branch of medicine that investigates the essential nature of disease, especially changes in body tissues and organs that cause or are caused by disease. Pathogenesis  The development of unhealthy conditions or disease, or more specifically, the cellular events and reactions and other pathologic mechanisms that occur in the development of disease. Pathophysiology  Another commonly used term with reference to study of diseases is ‘pathophysiology’ comprised by two words: patho=suffering; physiology=study of normal function. Pathophysiology, thus, includes study of disordered function or breakdown of homeostasis in diseases. Why is pathology important to Physical Therapists? Because…  For the PT student, the discipline of pathology forms a vital bridge between initial learning phase of preclinical sciences and the final phase of clinical subjects.  Remember the prophetic words of one of the eminent founders of modern medicine in late 19th and early 20th century, Sir William Osler, “Your practice of medicine will be as good as your understanding of pathology.” Pathologists  Pathologists are the diagnosticians of disease.  Therefore, knowledge and understanding of pathology is essential for all would-be doctors, general medical practitioners and specialists since unless they know the causes, mechanisms, nature and type of disease, and understand the language spoken by the pathologist in the form of laboratory reports, they would not be able to institute appropriate treatment or suggest preventive measures to the patient. Disease SINCE PATHOLOGY IS THE STUDY OF DISEASE, THEN WHAT IS DISEASE? Disease  In simple language, disease is opposite of health i.e. what is not healthy is disease.  While disease is loss of ease (or comfort) to the body (i.e. dis-ease).  Disease can be defined as any abnormality or failure of the body to function properly and this may require medical treatment. Health IT IS COMPLEX Health  Health may be defined as a condition when the individual is in complete accord with the surroundings.  [The WHO has defined health as a state of complete physical, mental, and social well-being and not merely as the absence of disease or infirmity.]  All of these definitions' present health as an either/or circumstance, meaning an individual is either healthy or ill. Health Health is more accurately viewed as a continuum on which wellness on one end is the optimal level of function and illness on the other may be so unfavorable as to result in death.  Health is a dynamic process that varies with changes in interactions between an individual and the internal and external environments.  This type of definition recognizes health as an individual’s level of wellness  Thus, health and disease are not absolute but are considered as relative states.  Illness NOT DISEASE Illness  A term commonly confused with disease is illness.  While disease suggests an entity with a cause, illness is the reaction of the individual to disease in the form of symptoms (complaints of the patient) and physical signs (elicited by the clinician).  Though disease and illness are not separable, the study of diseases is done in pathology while the learning and management of illnesses is done in wards and clinics. Disease Vs Illness Disease Illness  Disease refers to a biologic or psychologic alteration that results in a malfunction of a body organ or system.  Illness is often defined as sickness or deviation from a healthy state, and the term has a broader meaning than disease.  Disease is usually a term used to describe a biomedical condition that is substantiated by objective data such as elevated temperature or presence of infection (as demonstrated by positive blood cultures).  Illness is the perception and response of the person to not being well. Disease Vs Illness Disease  Disease can occur in an individual without that person being aware of illness and without others perceiving illness.  However, a person can feel very ill even though no obvious pathologic processes can be identified. Illness  Illness includes disturbances in normal human biologic function and personal, interpersonal, and cultural reactions to disease. Terminologies  Patient is the person affected by disease.  Lesions are the characteristic changes in tissues and cells produced by disease in an individual or experimental animal.  Pathologic changes or morphology consist of examination of diseased tissues.  Pathologic changes can be recognised with the naked eye (gross or macroscopic changes) or studied by microscopic examination of tissues.  Causal factors responsible for the lesions are included in etiology of disease (i.e. ‘why’ of disease). Terminologies  Mechanism by which the lesions are produced is termed pathogenesis of disease (i.e. ‘how’ of disease).  Functional implications of the lesion felt by the patient are symptoms and those discovered by the clinician are the physical signs.  Clinical significance of the morphologic and functional changes together with results of other investigations help to arrive at an answer to what is wrong (diagnosis), what is going to happen (prognosis), what can be done about it (treatment), and finally what should be done to avoid complications and spread (prevention) (i.e. ‘what’ of disease). Characteristic Features of Diseases Aetiology of Disease  Aetiology refers to the cause of a disease.  Aetiological agents can be endogenous, in other words originating from within the body, or exogenous, coming from outside the body. Aetiology of Disease  Endogenous agents include genetic defects and endocrine disorders.  Exogenous agents include microorganisms such as viruses, bacteria and fungi that cause infections, chemicals, physical trauma and radiation. Aetiology of Disease-Endogenous  Endogenous agents include genetic defects and endocrine disorders.  Normal genes: Genetic factors influence susceptibility or resistance to disease  Susceptibility  HLA of fair skin to UV radiation (human leucocyte antigen) type influences predisposition to autoimmune disorders Aetiology of Disease-Endogenous  Endogenous agents include genetic defects and endocrine disorders.  Abnormal Genes: Mutations which lead to manifestation of disease  Many appear spontaneously  Others may appear following radiation  Hereditary diseases Aetiology of Disease  Exogenous agents include:  microorganisms such as viruses, bacteria and fungi that cause infections,  chemicals,  physical agents: trauma, extreme of temperatures, electrical power and radiation. Aetiology of Disease  Many diseases are said to be predictable and arise as a direct consequence of exposure to the causative agent.  Other diseases are considered probable in that they may be a consequence of the causative agent but the development of illness is not inevitable.  An individual can be infected with a pathogenic microorganism but the outcome of the disease may depend on other factors such as the nutritional and immune status of the affected person. Aetiology of Disease  Many diseases are of unknown cause and are said to be idiopathic. An example of this is hypertension, where more than 90% of cases are of unknown cause.  The treatment of idiopathic diseases is restricted to alleviating the symptoms.  Some conditions are caused by the effects of treatment and are called iatrogenic diseases (from the Greek word iatros, doctor). Aetiology of Disease  Occasionally a disease of unknown etiology is more commonly found in populations with certain dietary, occupational or lifestyle conditions called risk factors.  Some risk factors may be important in the development of the disease whereas others may make the individual more susceptible to disease. Predisposing factors are conditions or situations that make an individual more susceptible to disease. Pathogenesis  Every disease has a pathogenesis that describes the development of the disease or, more specifically, how the etiological agent(s) acts to produce the clinical and pathological changes characteristic of that disease.  Diseases have ‘natural histories’ that describe the typical patterns of how each disease usually progresses, its effects and its duration. The effects of the disease on the patient are referred to as morbidity.  Occasionally the morbidity of a disease may cause disability that, in turn, may restrict the activities of the patient. Pathogenesis  The mortality of a disease describes its possibility of causing death.  This is usually expressed as a percentage.  Some diseases have a rapid, often severe onset that is described as acute. Pathogenesis  However,  other diseases have a chronic onset and develop gradually over a relatively longer time.  Diseases rarely occur immediately following exposure to an etiological agent. Pathogenesis  In most cases, a period of time, the incubation period, must elapse before the disease becomes apparent.  In carcinogenesis, this period may last several decades and is referred to as the  latent period. With infectious diseases, the time between exposure and development of the disease is often characteristic of the infectious agent involved. Manifestation of Diseases  The aetiology of a disease and its pathogenesis produce clinical manifestations that include signs and symptoms of the disease.  A is an indication that a disease is present and something of which the patient complains, for example, nausea, malaise or pain.  A is something that the clinician specifically looks or feels for, such feels as redness or swelling of the skin, when examining the patient. symptom sign Manifestation of Diseases  Clinical signs and symptoms are often accompanied by structural or functional abnormalities, called lesions, in affected tissues that are responsible for ill health and usually cause the signs and symptoms of disease. Manifestation of Disease  The term syndrome is often applied to describe certain diseases that are characterized by multiple abnormalities that form a distinct clinical picture.  Some diseases frequently present with complications, that is, new or separate processes secondary to, and a consequence of, the initial disease.  The manifestations of a disease in a given person are not static and are affected by compensatory mechanisms in the body as well as by environmental influences and responses to treatment. Manifestation of Disease  Diseases often have a range of manifestations and their presence and severity may vary from patient to patient.  In addition to differences between individuals, differences occur within an individual at different stages of development, from infancy to old age. Outcome of a Disease prognosis of a disease is its likely outcome.  The  Prognoses can vary considerably between different diseases and, of course, can be influenced by treatment.  Hence when giving a prognosis, it is necessary to clarify if the disease is following its natural course or whether there is, or needs to be, medical or surgical intervention. Outcome of a Disease  With some diseases, especially some cancers, patients may go through a period of good health with a reduction or disappearance of the symptoms and the disease is said to be in remission.  However, a relapse may occur with a return of the disease symptoms following this period of apparent recovery. Classification of Diseases (example 1)  Infectious  Congenital  Immunological  Neoplastic  Endocrine  Traumatic  Homeostatic  Degenerative  Nutritional  Psychogenic  Toxic  Iatrogenic  Genetic  Idiopathic Classification of Diseases (example 2)  Topographic  Anatomic  Physiological  Pathological  Etiologic  Juristic  Epidemiological  Statistical Epidemiology of Disease  Epidemiology is the study of how diseases spread in populations in relation to their causal factors.  Consequently, epidemiology is largely concerned with the collection and interpretation of data about diseases in groups of people rather than in individuals. Epidemiology of Disease  The prevalence of a disease refers to the proportion of people in a population affected at a specific time.  The incidence rate is the number of new cases of a disease in a population occurring within a specified period of time. Investigating Disease Pathology Laboratories  Medical Microbiology  Immunology  Clinical Biochemistry  Hematology  Histopathology  Clinical Genetics Investigative Techniques          Autopsy Surgical Pathology / Histopathology Histochemistry Basic Microscopy Electron Microscopy Immunoflorescence Immunohistochemistry Cytogenetics Diagnostic Molecular Pathology Health Promotion & Disease Prevention Health Promotion  Health promotion as a concept and as an active process is built on the principles of selfresponsibility, nutritional awareness, stress reduction and management, and physical fitness.  Health promotion is not limited to any particular age or level of ability but rather extends throughout the life span from before birth (e.g., prenatal care) through old age, including anyone with a disability of any kind. Health Promotion  Health promotion programs that encompass the entire life span are applicable to people of both genders and all socioeconomic and cultural backgrounds, to those who have no health problems, and to those with chronic illnesses and disabilities.  Many types of health promotion programs are in existence such as health screening, wellness, safety, stress management, or support groups for specific diseases. Disease Prevention  Disease prevention has gained momentum and today is at the forefront of the health care industry.  It is now recognized and addressed by greater numbers of health care professionals that preventing disease is more cost-effective than treating disease. Disease Prevention  Many new areas of study have developed as a result of this paradigm shift in focus from treatment to prevention.  Scientists are revolutionizing the way we fight infection, manage chronic illness, and stay well.  For example, one group has coined the term immunotics to describe this new approach to preventing and treating disease. Disease Prevention-Preventative Medicine  Preventative Medicine as a branch of medicine is categorized as primary, secondary or tertiary.  Primary prevention is geared toward removing or reducing disease risk factors  Secondary prevention techniques are designed to promote early detection of disease and to employ preventive measures to avoid further complications.  Tertiary prevention measures are aimed at limiting the impact of established disease. What is YOUR role in Health Promotion & Disease Prevention? Read this webpage and Answer the following questions HTTPS://WWW.PHYSIO-PEDIA.COM/LAB_VALUE_INTERPRETATION Questions  What are the importance of Lab values?  What are the most common factors that can affect lab results?  How can lab values affect your plan of care as a therapist?  List 7 lab tests that are commonly done and state the purpose for each one. Reading Assignments  PATHOLOGY: Implications for the Physical Therapist, Goodman & Fuller  READ CHAPTER 1 & 6 (pg 197-208)  AND  PATHOLOGY ILLUSTRATED, Reid & Roberts  READ CHAPTER 1 Next Class  Cellular Pathology Morphology Necrosis/ Degeneration