Pathophysiology

Pathophysiology / Agenda What is pathophysiology ? Why do we study pathophysiology ? Concepts of Health and Disease Concepts of Health and Disease What is the Disease ? Etiology of Disease Etiology of Disease Pathogenesis of Disase Pathogenesis of Disase Outcome of Disease Outcome of Disease

What is pathophysiology? X Pathophysiology may be defined as the physiology of disease, of disordered function, or derangement of function seen in disease that is produced by the action of etiologic agents on susceptible tissues or organs. Pathophysiology includes also the study of the mechanisms underlying disease. study of the effect of disease on cell, tissue, organ and system.

What is pathophysiology? X A subject to explore the rule of origin and evolution of disease processes and the fundamental mechanisms. Pathophysiology can also mean the functional changes associated with or resulting from disease or injury

001Heart Attack / Myocardial Infarction

Why do we study pathophysiology ？ bridge subject basicsciences clinicalmedicine pathophysiologyPathophysiology is an important subject bridging Basic sciences and clinical medicine.

Why do we study pathophysiology X Enabling the students, clinicians and other practitioners to understand why and how diseases develop and various clinical manifestations appear, and what are the fundamental mechanisms.

Other names Also named: Physiopathology Physiology of Disease Physiology of Disordered Function

Difference from Physiology X Pathophysiology or Physiopathology is a convergence pathology with physiology. Pathology is the medical discipline that describes conditions typically observed during a disease state, whereas physiology is the biological discipline that describes processes or mechanisms operating within an organism.

Difference from Pathology X Pathology emphasizes the structural changes Pathophysiology focuses on the functional and metabolic alterations and the mechanisms

Difference from Pathology X Pathology describes the abnormal or undesired condition, whereupon pathophysiology seeks to explain the physiological processes or mechanisms whereby such condition develops and progresses

■ ■ Health Concepts of Health and Disease X The World Health Organization affirms that health is “more than the absence of disease,” but rather a state of “complete physical, mental, and social well-being,” This definition sets a lofty goal for patients seeking health as well as for health care professionals. health ● Factor in health ▲ ▲ physical well-being ▲ ▲ mental well-being ▲ ▲ social well-being

Homeostasis Neural regulated Humoral regulated Signal regulated in cell ▲ ▲ disease is caused by the etiological factors. ▲ ▲ base of disease is deregulated homeostasis. Factor in disease ● Factor in disease ■ ■ Disease X Disease is referred as aberrant manifestation of deregulated homeostasis caused by harmful agents. Disease is defined as an abnormal life process which is induced by disorders of homeostasis under the action of certain cause(s). deregulated

What is the Disease? X It is the “State in which an individual exhibits an anatomical, physiological, or biochemical deviation from the normal” Disease may be defined as :Disease may be defined as : an abnormal alteration of structure or function in any part of the body.

Various Classification of Disease 1  Developmental – genetic, congenital.  Acquired: *Inflammatory – Trauma, infections, immune, etc. *Neoplastic – tumors cancers *Degenerative – ageing. *Metabolic. *Iatrogenic: Drug induced.

Various Classification of Disease 2 Anatomical  Organ  System Developmental (age)  Neonatology  Pediatrics  Adolescent  Adult  Geriatrics Etiological

Homeostasis internal constancy or a stable internal environment A “body in balance” is in homeostasis Homeostatic regulation ---- works by using feedback loops Feedback loopsFeedback loops utilize 3 components (1) receptor (2) control center (3) effector –2 types of feedback loops (1) negative feedback –Restores any change back to normal –Resembles “teeter-totter” –Stabilizing –Most common (2) positive feedback –Exaggerates the change –Resembles “domino effect” –Stimulating –Least common

Disease Process 5 Components  Epidemiology  Etiology  Pathophysiology  Clinical Manifestations  Outcome “COPE”

Epidemiology  Define  Factors:  Predisposing,  Precipitating Herpes D Virus

Epidemiology X is the study of the patterns, causes, and effects of health and disease conditions in defined populations. It is the cornerstone of public health, and informs policy decisions and evidence-base medicine by identifying risk factors for disease and targets for preventive medicine.

Etiology X ■ Concept of Etiological Factors & Predisposing Etiologic factors involved in diseases include causative, predisposing and precipitating factors, which contributes to the onset of diseases. Etiological factors ● Etiological factors ▲ ▲ The factor that causes the disease and determine the clinical features of the disease ▲ ▲ Among the etiological factors, a wide range of extrinsic factors in the environment and intrinsic factors in the body must be considered.

 Environmental agents: Physical Chemical Nutritional Infections Immunological Psychological  Genetic Factors: Age Genes Multifactorial As Diabetes, Hypertension As Diabetes, Hypertension Cancer Cancer Etiology: What is the cause? X

One etiologic agent several diseases, as smoking.One etiologic agent several diseases, as smoking. Disease Several etiologic agents one disease, as diabetes. Several etiologic agents one disease, as diabetes. Disease One etiologic agent - one disease, as Malaria. One etiologic agent - one disease, as Malaria. Etiology

Etiological factors Biological agents Chemical agents Physical agents Nutritional imbalance Extrinsic Factors

Etiological factors Genetic factors Congenital factors Immunological factors Psychological factors Intrinsic Factors

■ Classification of etiological factors ▲ biological agents Factors of environment ● Factors of environment ▲ physical agents ▲ chemical agents Inherited factors ● Inherited factors ▲ gene mutation 【 genetic predisposition 】 The genetic mutations cause problems only when a person is eposed to certain environmental agents. ▲ chromosomal aberration

Congenital factors ● Congenital factors The disorders are of a developmental nature and most of them are nongenetic. Nutritional imbalance ● Nutritional imbalance Either excesses or deficiencies of nutrients predispose cells to injury.

Immunological factors ● Immunological factors ▲ immunodeficiency disease ▲ autoimmune disease ▲ anaphylactic reaction Psychological and social factors ● Psychological and social factors Anxiety, strong or persistent psychological stimulation or stress may lead to mental illness and may be related to some diseases, such as hypertension, peptic ulcer, coronary heart disease, and depression.

Predisposing factors The function of these factors is to intensify the effects of causative factors and promote the onset and development of diseases.

Predisposing Factors X Age Young are prone to accidents Getting diseases such as diabetes, heart disease, and certain cancers increase with age Very old are prone to drug interactions Sex More frequent in woman: MS, osteoporosis More frequent in men: gout, Parkinson’s disease Lifestyle Examples of harmful lifestyle:  Perilous occupation  Smoking  Excess alcohol  Poor nutrition  Sedentary activity

Environment Air pollution Water pollution Poor living conditions Excessive noise Chronic psychological stress Heredity Deals with genetic predisposition (inheritance)  Genetic predisposition + certain type of environment = mental retardation, lung cancer, etc. Preventive health care The best treatment of a disease is prevention !! Deals with altering risk factors that can be changed Predisposing Factors X

Predisposing factors for colorectal Cancer Poor diet (more fresh food, increase fiber) Sedantary life style Decreased regular physical activity Heredity (regular screening) Age (digestion slows) COLONOSCOPY after 50

Precipitating Factors Natural conditions Physical condition Social condition aftershave-asthma The factors that promote the development of disease and influences the timing of illness onset The factors that start to outset of disease.

Pathogenesis X The sequence events in the response of the cells or tissues to the etiologic agent, from the initial stimulus to the ultimate expression of the disease,”from the time it is initiated to its final conclusion in recovery or death” The pathogenesis of a disease is the mechanism that causes the disease. For example bacterial pathogenesis is the mechanism by which bacteria cause infectious illness.

Pathogenesis X Pathogenesis of disease refers to the rules and mechanisms underlying the development or evolution of diseases. It studies: how the primary pathological agents cause disease in organism and how the disease develops. how the primary pathological agents cause disease in organism and how the disease develops. ■ Basic Mechanisms of Disease Neural mechanism Humoral mechanism Cellular mechanism Molecular mechanism

Neural mechanism Neural system plays a central role in regulating entire life activities; the disturbance occurred in neural system and in periphery organs are mutually affected. Encephalitis B virus can damage neural system directly; some poisons may interrupt the metabolism of neural cells and the production and release of neurotransmitters.

Humoral mechanism (humoral factors, cytokines) Humoral regulation is crucial in maintaining internal homeostasis. Humoral dysfunction generally indicates the alterations in number and in activities of some humoral factors( hormones, chemical mediators, cytokines). They function through endocrine, paracrine, and autocrine to regulate the metabolism and activities of the cells.

During the development of diseases, the regulations in humoral and neural system are usually simultaneous e.g. disturbance of neural-humoral regulation in hypertension: constant stress --- dysfunction of neural system (cerebral cortex and hypothalamus) ---sympathetic-adrenal medulla system ----increased secretion of norepinephrine and epinephrine --- constriction of arteries/ constriction of renal afferent arterioles will activate renin angiotensin-aldosterone system, and finally causes hypertension.

Cellular and molecular mechanism Cellular and molecular damages or alterations are fundamental in the development of disease. Strong acid and alkali destroy the cells with no selection; hepatitis virus damages specifically the hepatocytes. Disease genomics: Disease proteomics

Pathophysiology Focus Disease Mechanisms  Genetic  Internal  External Pathogenesis Morphology  Gross  Histological

Morphology: X Structural changes in disease. Tumor in a cancer. Ulcer in an infection. Atrophy in dementia. Gross & Microscopic.

■ General Rules for Pathogenesis of Diseases Damage and anti-damage responses ● Damage and anti-damage responses Damages are usually made when a variety of harmful insults attack the body. During this process, anti-damage responses are also induced in the body to restore the normal situation. pain Infection (fever) plasma loss pain Infection (fever) plasma loss shock ischemia & injury of Cells Bp↓, blood volume ↓ shock ischemia & injury of Cells Bp↓, blood volume ↓ Severe burn Severe burn Damage Anti-damage Stress WBC↑, Blood coagulation↑ SAMS excitation(+) Stress WBC↑, Blood coagulation↑ SAMS excitation(+) C.O↑, Blood redistribution C.O↑, Blood redistribution Rehabilitation blood flow heart & brain↑ Rehabilitation blood flow heart & brain↑ Anti-infection↑, plasma loss↓ SAMS: Sympathetico-adrenal-medullay system; c.o: cardiac output

Clinical Manifestations X  Symptoms /Syndrome Patient Report Subjective Related Terms: Prodromal, Insidious, Latent  Signs Health care exam Observable phenomena Objective  Diagnostic Criteria Laboratory results Imaging Biopsy Digital Thermal Imaging

Clinical Manifestations Displaying clues and symptoms of an illness Clinical manifestations are the observable symptoms by which a disease may be diagnosed by a physician. It is how a disorder 'manifests' itself to an observer.

What is Osteoarthritis: Signs & Symptoms

Signs & Symptoms Relating to disease, noticable or preceptible interpretation of modified health condition A signal that is expressed by an ill individual and is often considered a personal meaning

Signs vs symptoms X Signs are the physical manifestation of injury, illness or disease. A high temperature a rapid pulse, low blood pressure, bruising can be called as signs symptoms are what a patient experiences about the injury, illness or disease Chills, shivering, fever, nausea, shaking and vertigo are the symptoms.

Pneumonia signs & Symptoms Flu like Persistent cough Fever Shortness of breath Chest pain Chills sweath Cough, with thick, sticky fluid Fatigue and muscle aches Nausea, vomiting or diarrhea Headache

Common symptoms (Diabetes) Frequent urination Excessive thirst Unexplained weight loss Extreme hunger Sudden vision changes Tingling or numbness in the hands or feet Feeling very tired much of the time Very dry skin Sores that are slow to heal More infections than usual

Latent symptoms: Existing or present but concealed or inactive. X Prodromal symptoms: An early symptom indicating the onset of an attack or a disease. Insidious/Vague symptoms: There are a number of diseases, some of them very serious, which only cause mild or vague symptoms. People may not even really feel sick, but just have a feeling that things are not quite right.

Asymptomatic X Absence of any observable symptoms even though lab tests announce a disease is present

The course of a disease X An acute disease has relatively sudden onset and lasts for a short term, An acute disease has relatively sudden onset and lasts for a short term, a chronic disease, sometimes begins with an acute phase, usually lasts for a long period of time. a chronic disease, sometimes begins with an acute phase, usually lasts for a long period of time. subacute subacute

Eczema-Dermatological Definition An acute, subacute but usually chronic pruritic inflammation of the epidermis and the dermis, often occurring in association with a personal family history of hay fever, asthma, allergic rhinitis or atopic dermatitis.

Characteristics of Acute Eczema Well demarcated plaques of erythema and edema on which are superimposed and closely spaced small vesicles filled with clear fluid with punctate erosions and crusting Distribution may be isolated and localized or general

Acute Eczema Note the erythema, vesicles and swelling

Characteristics of Subacute Eczema Plaques of mild erythema with small dry scales and or superficial desquamation, sometimes associated with small red, pointed or round papules Distribution may be isolated and localized or general

Subacute Eczema Note erythema, swelling and desquamation

Characteristics of Chronic Eczema Plaques with deepening of the skin lines with satellite, small, firm flat or round top papules, excoriations and pigmentations or mild erythema lichenifica tion

Chronic Eczema Note lichenification, scaling and fissuring

Acute - Subacute - Chronic Swelling and erythema Punctate erythema, desquamation Lichenification

Outcome Expected  Prognosis Actual  Cure  Remission  Exacerbation  Complication  Palliative  Death

Prognosis X Expected outcome of the disease, It is the clinician's estimate of the severity and possible result of a disease.

Outcome of disease X Complete recovery Incomplete recovery Death

Outcome X Cure: Restoration of health; recovery from disease Remission: A period during which symptoms of disease are reduced (partial) or disappear (complete remission) Exacerbation: An increase in the severity of a disease or in any of its signs or

Outcome X Complication; secondary disease or condition that develops in the course of a primary disease or condition and arises either as a result of it or from independent causes. Palliative: Medications and treatments are said to have a palliative effect if they relieve symptoms without having a curative effect on the underlying disease or cause

Complete recovery The best outcome of a disease: the etiological factors disappear the pathologically altered metabolism, structure and function are perfectly restored the symptoms and signs of the disease disappear entirely homeostasis is recovered

Incomplete recovery The main symptoms and signs disappear but some pathological changes are left behind, namely sequela. Sequela is generally brought about by the compensatory response to maintain a relatively normal activity. For example, the permanent damage to the heart valve after rheumatic fever.

■ Death The cessation of heart-beats and breath is used as the criterion of death of a body. Brain death ● Brain death The functions of cerebrum and brain stem stop forever.

Brain Death (WHO criteria ) X Cessation of spontaneous respiration Irreversible coma Absence of cephalic reflexes and dilated pupils Absence of any electrical activity of the brain Absence of brain blood flow

Terms Used In Pathophysiology X Pathology = study of disease Pathogenesis = the development of a disease Diseases develops in stages  Infectious disease example: (A)incubation (b)disease (c)convalescence Pathophysiology = the study of the functional changes associated with a specific disease  How the disease affects specific functions of the body Subjective findings  The patient’s symptoms  Described by the patient----(the patient’s history) Objective findings  Health provider’s findings---( the physical exam) Occurrence of disease defined by 2 factors Incidence = # new cases per unit of time Prevalence = # new & old cases per unit of time

Disease terminology X  Etiology = cause of the disease  Idiopathic = disease with unknown cause  Iatrogenic = disease caused by human intervention  Congenital diseases = diseases occurring at birth  Syndrome = common cause of different signs & symptoms  Remission = period when symptoms & signs of disease abates  Exacerbation = period when symptoms & signs increase  Endemic disease = disease native to local area  Epidemic = many people affected in a given area  Pandemic = many people affected in large areas  Incubation = latent period of the disease before develop signs & symptoms  Prognosis = probability for recovery  Morbidity = disease rates within a group  Mortality = death rates within a group  Epidemiology = how the disease occurs & spreads through an area

I hear, I forget I see, I remember I do, I understand Chinese Proverb..