Introduction to Pathophysiology PDF

## Introduction to Pathophysiology ### Terms of the Disease Process | Terms | Definition | |---|---| | Diagnosis | Refers to the identification of a specific disease through the evaluation of signs and symptoms, laboratory tests or other tools. | | Etiology | The causative factors in a particular...

## Introduction to Pathophysiology ### Terms of the Disease Process | Terms | Definition | |---|---| | Diagnosis | Refers to the identification of a specific disease through the evaluation of signs and symptoms, laboratory tests or other tools. | | Etiology | The causative factors in a particular disease. There may be one or several causative factors. Etiologic agents include congenital defects, inherited or genetic disorders, microorganisms such as viruses or bacteria, immunologic dysfunction, metabolic derangements, degenerative changes, malignancy, burns and other trauma, environmental factors, and nutritional deficiencies. | | Idiopathic | When the cause of a disease is unknown. | | Iatrogenic | A treatment, a procedure, or an error may cause a disease. *eg.* A bladder infection following catheterization, or bone marrow damage caused by a prescribed drug. | Predisposing factors | Encompass the tendencies that promote development of a disease in an individual. A predisposing factor indicates a high risk for the disease but not certain development. Predisposing or high-risk factors may include age, gender, inherited factors, occupational exposure, or certain dietary practices. | | A prophylaxis | is a measure designed to preserve health (as of an individual or society) and prevent the spread of disease. *Daily baby aspirin to prevent myocardial infarction.* | | Prevention of disease | Is closely linked to etiology and predisposing factors for a specific disease. Preventive measures include vaccinations, dietary or lifestyle modifications, and cessation of potentially harmful activities such as smoking. | ### (Continued) Terms of Characteristics of Disease | Terms | Definition | |---|---| | Remissions and exacerbations | May mark the course or progress of a disease. A *remission* is a period or condition in which the manifestations of the disease subside, either permanently or temporarily. An *exacerbation* is a worsening in the severity of the disease or in its signs/symptoms. | | A precipitating factor | Is a condition that triggers an acute episode, such as a seizure in an individual with a seizure disorder. | | Complications | Are new secondary or additional problems that arise after the original disease begins. *For example, following a heart attack, a person may develop congestive heart failure, a complication.* | | Therapy or therapeutic interventions | Are treatment measures used to promote recovery or slow the progress of a disease. These measures may include surgery, drugs, physiotherapy, alternative therapies, or behavior modification | | Sequelae | Are the potential unwanted outcomes of the primary condition, such as paralysis following recovery from a stroke. | | Convalescence | Is the period of recovery and return to the normal healthy state; it may last for several days or months | ### Terms of Disease Prognosis |Terms | Definition | |---|---| | Prognosis | The probability or likelihood for recovery or other outcomes. The probability figures used in prognosis are based on average outcomes, and there may be considerable variation among affected individuals. | | Morbidity | Indicates the disease rates within a group; this term is sometimes used to indicate the functional impairment that certain conditions such as stroke cause within a population | | Mortality figures | Indicate the relative number of deaths resulting from a particular disease. | | An autopsy or postmortem examination | May be performed after death to determine the exact cause of death or determine the course of the illness and effectiveness of treatment. An autopsy is an examination of all or part of the body by a pathologist. It includes gross and microscopic examination of tissues, organs, and fluids and can include a variety of tests depending on individual circumstances. | | Epidemiology | Is the science of tracking the pattern or occurrence of disease. Epidemiologic records include data on the transmission and distribution of diseases and are particularly important in the control of infectious diseases and environmentally related diseases. | ### (Continued) Terms of Disease Prognosis | Terms | Definition | |---|---| | The occurrence of a disease | Is tracked by recording two factors, the *incidence* and the *prevalence*. The *incidence* of a disease indicates the number of new cases in a given population noted within a stated time period. A significant increase or decrease in incidence of a specific disease may be analyzed to determine the responsible factors. *Prevalence* refers to the number of new and old or existing cases within a specific population and time period. Note that prevalence is always a larger figure than incidence. | | Epidemics | Occur when there are a higher than expected number of cases of an infectious disease within a given area, whereas pandemics involve higher numbers of cases in many regions of the globe. *Influenza may occur sporadically as well as in epidemic or pandemic outbreaks.* | | Communicable diseases | Are infections that can be spread from one person to another. Some of these must be reported to health authorities. | | Notifiable or reportable diseases | Must be reported by the physician to certain designated authorities. The specific diseases required to be reported may change over time. The requirement of reporting is intended to prevent further spread of the disease and maintain public health. | ### Introduction to Cellular Changes * The cells have mechanisms by which they can adapt their growth and differentiation to altered conditions in the body. * Some minor alterations, such as increases in breast and uterine tissue during pregnancy, are normal adaptations to change in the body. * Frequently such changes are reversible after the stimulus is removed. * Abnormal changes are not necessarily a precursor to permanent tissue damage or the development of tumors or cancer, but it is important to determine the cause and monitor any abnormality to reduce the risk of serious consequences. ### Terms Used for Common Cellular Adaptations | Terms | Definition | |---|---| | Atrophy | refers to a decrease in the size of cells, resulting in a reduced tissue mass. *Common causes include reduced use of the tissue, insufficient nutrition, decreased neurologic or hormonal stimulation, and aging. An example is the shrinkage of skeletal muscle that occurs when a limb is immobilized in a cast for several weeks.* | | Hypertrophy | Refers to an increase in the size of individual cells, resulting in an enlarged tissue mass. This increase may be caused by additional work by the tissue. *A common example of hypertrophy is the effect of consistent exercise on skeletal muscle, leading to an enlarged muscle mass.* | | Hyperplasia | Is defined as an increased number of cells resulting in an enlarged tissue mass. In some cases, hypertrophy and hyperplasia occur simultaneously, as in the uterine enlargement that occurs during pregnancy. In certain instances there may be an increased risk of cancer when hyperplasia occurs. | | Metaplasia | Occurs when one mature cell type is replaced by a different mature cell type. *This change may result from a deficit of vitamin A.* | ### (Continued)Terms Used for Common Cellular Adaptations | Terms | Definition | |---|---| | Dysplasia | Is the term applied to tissue in which the cells vary in size and shape, large nuclei are frequently present, and the rate of mitosis is increased. This situation may result from chronic irritation infection, or it may be a precancerous change | | Anaplasia | Refers to cells that are undifferentiated with variable nuclear and cell structures and numerous mitotic figures. Anaplasia is seen in most but not all malignant tumors and is the basis for grading the aggressiveness of a tumor. | | Neoplasia | Means "new growth," and a neoplasm is commonly called a tumor. Tumors are of two types, benign and malignant. Malignant neoplasms are referred to as cancer. Benign tumors do not necessarily become malignant. | ### Terms of Characteristics of Disease | Terms | Definition | |---|---| | Pathogenesis | Refers to the development of the disease or the sequence of events involved in the tissue changes related to the specific disease process. | | The onset of a disease | Sudden and obvious or acute-for example, gastroenteritis with vomiting, cramps, and diarrhea-or the onset may be insidious, best described as a gradual progression with only vague or very mild signs. | | An acute disease | Indicates a short-term illness that develops quickly with marked signs such as high fever or severe pain-for example, acute appendicitis. | | A chronic disease state | Is often a milder condition developing gradually, such as rheumatoid arthritis, but it persists for a long time and usually causes more permanent tissue damage. | | A subclinical state | Exists in some conditions in which pathologic changes occur but the patient exhibits no obvious manifestations, perhaps because of the great reserve capacity of some organs. For example, kidney damage may progress to an advanced stage of renal failure before symptoms are manifested. | ### (Continued) Terms of Characteristics of Disease | Terms | Definition | |---|---| | An initial latent or "silent" stage | In which no clinical signs are evident, characterizes some diseases. In infectious diseases this stage may be referred to as the *incubation period*, which is the time between exposure to the microorganism and the onset of signs or symptoms; it may last for a day or so or may be prolonged, perhaps for days or weeks. Often the disease agent may be communicable during this incubation period. | | The prodromal period | Comprises the time in the early development of a disease when one is aware of a change in the body, but the signs are nonspecific; for example, fatigue, loss of appetite, or headache. A sense of feeling threatened often develops in the early stage of infections. Laboratory tests are negative during the prodromal period; thus it is difficult to confirm a diagnosis. | | The manifestations of a disease | Are the clinical evidence or effects, the signs and symptoms, of disease. These manifestations, such as redness and swelling, may be *local*, or found at the site of the problem. Or signs and symptoms may be *systemic*, meaning they are general indicators of illness, such as fever. | ### (Continued) Terms of Characteristics of Disease | Terms | Definition | |---|---| | Signs | Are objective indicators of disease that are obvious to someone other than the affected individual. Signs can be either *local*, found at the site of the problem (such as a skin rash) or *systemic*, which are general indicators (such as a fever).. | | Symptoms | Are subjective feelings, such as pain or nausea. Both signs and symptoms are significant in diagnosing a particular problem. | | Lesion | Is the term used to describe a specific local change in the tissue. Such a change may be microscopic, as when liver cells are examined for pathologic change, or highly visible, such as a blister observed on the skin | | A syndrome | Is a collection of signs and symptoms, often affecting more than one organ, that usually occur together in response to a certain condition. | | Diagnostic tests | Are laboratory tests that assist in the diagnosis of a specific disease. The appropriate tests are ordered on the basis of the patient's manifestations and medical history, the clinical examination, and the patient's answers to specific questions. | ### Cell Damage and Necrosis | Terms | Definition | |---|---| | Apoptosis | Refers to programmed cell death, a normal occurrence in the body, which may increase when cell development is abnormal, cell numbers are excessive, or cells are injured or aged. | | Necrosis | refers to the death of one or more cells or a portion of tissue or organ as a result of irreversible damage and not a programmed cellular event. | There are many ways of injuring cells in the body, including the following: * Ischemia, a decreased supply of oxygenated blood to a tissue or organ, due to circulatory obstruction. * Physical agents, excessive heat or cold, or radiation exposure. * Mechanical damage such as pressure or tearing of tissue * Chemical toxins * Microorganisms such as bacteria, viruses, and parasites * Abnormal metabolites accumulating in cells * Nutritional deficits * Imbalance of fluids or electrolytes * Hypoxia.... *reduced oxygen in the tissue may occur locally because of a blocked artery or systemically because of respiratory impairment.* * Anaerobic metabolism....... *in the absence of oxygen, anaerobic metabolism occurs in the cell, leading to a decrease in pH from buildup of lactic acid and further metabolic impairment.* * Necrosis is the term used when a group of cells die and cause further damage due to cellular disintegration.