Genetics: osteoporosis
SECTION I Pathophysiology: Background and Overview, 1
CHAPTER 1 Introduction to Pathophysiology, 1
CHAPTER 2 Fluid, Electrolyte, and Acid-Base Imbalances, 14
CHAPTER 3 Introduction to Basic Pharmacology and Other Common Therapies, 40
CHAPTER 4 Pain, 53
SECTION II Defense/Protective Mechanisms, 65
CHAPTER 5 Inflammation and Healing, 65
CHAPTER 6 Infection, 88
CHAPTER 7 Immunity, 114
SECTION III Pathophysiology of Body Systems, 142
CHAPTER 8 Skin Disorders, 142
CHAPTER 9 Musculoskeletal System Disorders, 161
CHAPTER 10 Blood and Circulatory System Disorders, 184
CHAPTER 11 Lymphatic System Disorders, 213
CHAPTER 12 Cardiovascular System Disorders, 223
CHAPTER 13 Respiratory System Disorders, 272
CHAPTER 14 Nervous System Disorders, 325
CHAPTER 15 Disorders of the Eyes, Ears, and Other Sensory Organs, 385
CHAPTER 16 Endocrine System Disorders, 400
CHAPTER 17 Digestive System Disorders, 427
CHAPTER 18 Urinary System Disorders, 488
CHAPTER 19 Reproductive System Disorders, 514
SECTION IV Factors Contributing to Pathophysiology, 545
CHAPTER 20 Neoplasms and Cancer, 545
CHAPTER 21 Congenital and Genetic Disorders, 565
CHAPTER 22 Complications of Pregnancy, 579
CHAPTER 23 Complications of Adolescence, 588
CHAPTER 24 Complications of Aging, 597
Section V Environmental Factors and Pathophysiology, 606
CHAPTER 25 Immobility and Associated Problems, 606
CHAPTER 26 Stress and Associated Problems, 611
CHAPTER 27 Substance Abuse and Associated Problems, 617
CHAPTER 28 Environmental Hazards and Associated Problems, 624
Appendices, 631
Glossary, 654
Index, 663
GOULD’S Pathophysiology for the Health Professions SIXTH EDITION
Evolve Student Resources for Gould’s Pathophysiology for the Health Professions, Sixth Edition, include the following:
• Animations
• Answer Key for Study Questions in the book
Activate the complete learning experience that comes with each textbook purchase by registering at
http://evolve.elsevier.com/Hubert/Goulds/
YOU’VE JUST PURCHASED
MORE THAN A TEXTBOOK!
REGISTER TODAY!
You can now purchase Elsevier products on Evolve! Go to evolve.elsevier.com/html/shop-promo.html to search and browse for products.
2015v1.0
http://evolve.elsevier.com/Hubert/Goulds/
http://evolve.elsevier.com/html/shop-promo.html
GOULD’S Pathophysiology for the Health Professions
SIXTH EDITION
Robert J. Hubert, BS Laboratory Coordinator Iowa State University Department of Animal Sciences Ames, Iowa
Karin C. VanMeter, PhD Independent Consultant, Biomedical
Sciences Ames, Iowa
3251 Riverport Lane St. Louis, Missouri 63043
GOULD’S PATHOPHYSIOLOGY FOR THE HEALTH PROFESSIONS, SIXTH EDITION
ISBN: 978-0-323-41442-5
Copyright © 2018, 2014, 2011, 2006, 2002, 1997 by Saunders, an imprint of Elsevier Inc.
No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions
Senior Content Development Manager: Luke Held Content Development Specialist: Jennifer Wade Publishing Services Manager: Julie Eddy Senior Project Manager: Richard Barber Design Direction: Brian Salisbury
Printed in Canada
Last digit is the print number: 9 8 7 6 5 4 3 2 1
Notices
Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds or experiments described herein. Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made. To the fullest extent of the law, no responsibility is assumed by Elsevier, authors, editors or contributors for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.
ISBN: 978-0-323-41442-5
http://www.elsevier.com/permissions
We would like to dedicate this book to the memory of Barbara E.
Gould, MEd. We hope that this book, the legacy of her work, will
instill her passion for teaching and learning and will continue to
inspire health profession students and educators worldwide.
Robert Hubert Karin VanMeter
This page intentionally left blank
vii
Reviewers
Julie Alles, MSCTE, RHIA Assistant Professor/Program Director Health
Information Management Allied Health Sciences Grand Valley State University Grand Rapids, Michigan
Zoe Atamanchuk Canada
Janet Ballard, Med., BSN, RN Director of Allied Health and Practical Nursing EHOVE Adult Career Center Allied Health Department Milan, Ohio
Jason Berry, MSN, RN Nursing Instructor Nursing Department Winston Salem State University Winston Salem, North Carolina
Bonnie Carmack, MN, ARNP, NP Adjunct Faculty Seminole State College Department of Health Sciences Sanford, Florida
Teresa Cowan, DA, BS, MS Department Chair of Health Sciences Baker College of Auburn Hills Health Sciences Department Auburn Hills, Michigan
Heather Duval-Foote, BAS, RDMS Instructor/Clinical Coordinator Diagnostic Medical
Sonography The University of Findlay Diagnostic Services Department College of Health Professions Findlay, Ohio
Daniel F. Muñoz González, MSMLS, MLS(ASCP) CMPBT MB Assistant Professor of Medical Laboratory Sciences,
Clinical Chemistry, and Molecular Diagnostics Department of Medical Laboratory Sciences School of Health Professions Andrews University Berrien Springs, Michigan
Marina Hdeib, MA, RDMS Clinical Associate Professor School of Health Professions University of Missouri-Columbia Department of Clinical and Diagnostic Sciences Columbia, Missouri
Lily Mauer, RPh, BSc. Pharm. PEBC Registered Pharmacist Instructor NorQuest College Allied Health Careers, Faculty of Health and
Community Studies Edmonton, Alberta, Canada
Susan Stout, MHS, BS, RN Program Director of Science Baker College of Muskegon, Michigan Department of Health Science Muskegon, Michigan
viii
Preface
This textbook provides an introduction to pathophysiology for students in a variety of academic programs for the health professions at colleges and universities. Major disorders are described as well as selected additional diseases with the intention of providing information on a broad spectrum of diseases with one or more distinguish- ing features for each. It is anticipated that additional information and resources pertinent to the individual’s professional needs may be added to classroom presenta- tions and assignments. We trust that students will enjoy studying these topics and proceed with enthusiasm to more detailed studies within their individual specialties.
Organization
The textbook is organized into five major sections followed by the appendices:
Section I—Basic Concepts of Disease Processes • Introduction to pathophysiology includes medical
terminology and basic cellular changes. • Topics such as fluid, electrolyte, and acid-base imbal-
ances, basic pharmacology and pain are covered. • The core information for each topic is complemented
by the inclusion of a specific disease/condition as an immediate clinical application at the end of each chapter.
Section II—Defense/Protective Mechanisms • Topics such as inflammation and healing, infection,
and immunity are covered. • Specific areas included are a review of body defenses,
healing involved in specific trauma such as burns, basic microbiology, review of the immune system components, and mechanisms.
Section III—Pathophysiology of Body Systems • Selection of specific disorders is based on incidence
and occurrence, as well as on the need to present a variety of pathophysiological processes and etiologies to the student.
• For major disorders, information is provided on pathophysiology, etiology, clinical manifestations,
significant diagnostic tests, common treatment modali- ties, and potential complications.
• Other selected diseases are presented in less detail, but significant, unique features are highlighted.
Section IV: Factors Contributing to Pathophysiology • Normal physiological changes related to cancer,
adolescence, pregnancy, and aging, with their relevance and effect on disease processes and the treatment of the affected individual, are described.
• Specific disorders associated with cancer and the developmental stages are discussed.
Section V: Environmental Factors and Pathophysiology • Factors such as immobility, stress, substance abuse,
and environmental hazards are the major components in this section.
• Effects of the various environmental factors on the various body systems and potential complications beyond physical pathologies are discussed.
• New research and data are included as these are areas of increasing concern with regard to pathophysiology and patient health.
Appendices—additional information: • Ready References include lists of anatomic terms,
abbreviations and acronyms, a selection of diagnostic tests, an example of a medical history, a disease index, and drug index.
• A glossary and a list of additional resources complete this resource.
Format and Features
The basic format as well as the straightforward, concise approach remains unchanged from the previous editions. Some material has been reorganized to improve the flow of information and facilitate comprehension. Many features related to the presentation of information in this textbook continue as before. • Generic learning objectives are included in each chapter.
Instructors may modify or add applicable objectives for a specific professional program.
P R E FAC E ix
What’s New?
• Information on specific diseases has been updated throughout.
• The specific disorders for each body system have been expanded to reflect current trends and research.
• A broader emphasis on all allied health professions has been incorporated.
• Sections and chapters have been reorganized to present the student with a building block approach: basic science and how it relates to human biology, the body’s various mechanisms that respond to the disorders/diseases, the general overview of body systems and their specific disorders, other biological factors outside of the physiology of each system that contribute to instances of disorders/disease and, finally, those environmental factors not directly attributed to a biological function or condition that may contribute to pathophysiology throughout a number of body systems.
• Figures have been updated with new photographs and illustrations to help in the recognition and identification of the various concepts and specific disorders.
• Tables have been updated with new information that has been made available since the previous edition.
• Additional resources have been expanded and updated. • Study questions and Think About questions have been
reviewed and updated to cover new material in the chapter. The Apply Your Knowledge questions have replaced the Challenge questions in the previous editions.
• The Study Guide associated with this text has been updated to reflect the most recent information regard- ing various disorders.
Guidelines for Users
Certain guidelines were developed to facilitate the use of this textbook by students with diverse backgrounds studying in various health science programs. As well as ongoing general changes, some professional groups have developed unique practice models and language. In some disciplines, rapid changes in terminology have occurred, creating difficulty for some students. For example, current terms such as chemical dependency or cognitive impairment have many synonyms, and some of these are included to enable students to relate to a more familiar phrase. To avoid confusion, the common, traditional terminology has been retained in this text. • The recipient of care or service is referred to as a patient. • When a disease entity refers to a group of related
disorders, discussion focuses on either a typical rep- resentative of the group or on the general characteristics of the group.
• Key terms are listed at the beginning of the chapter. They are presented in bold print and defined when initially used in the chapter. Key terms are not indicated
• Cross-references are included, facilitating access to information.
• In the discussion of a particular disorder, the pathophysi- ology is presented first because this “sets the stage,” describing the basic change(s) in the body. Once the student understands the essence of the problem, he or she can easily identify the role of predisposing factors or causes and relate the resulting signs and symptoms or complications. Diagnostic tests and treatment also follow directly from the pathophysiology.
• Changes at the cellular level are included when significant.
• Brief reviews of normal anatomy and physiology are presented at the beginning of each chapter, to remind students of the structures and functions that are fre- quently affected by pathological processes. A review of basic microbiology is incorporated into the chapter on infections. Additional review material, such as the pH scale or the location of body cavities, may be found in the Appendices.
• Numerous illustrations, including flow charts, schematic diagrams, and photographs, clarify and reinforce textual information, as well as offer an alternative visual learning mode, particularly when complex processes are involved. Illustrations are fully labeled, including anatomical structures and pathologic changes. Different colors may be used in a figure to distinguish between the various stages or factors in a process.
• Tables summarize information or offer comparisons, which are helpful to the student in selecting the more significant information and for review purposes.
• Brief reference to diagnostic tests and treatment measures promotes understanding of the changes occurring during a disease.
• Questions are found in boxes throughout the text to stimulate application and review of new concepts. “Apply Your Knowledge” questions are based on review of normal physiology and its application, “Think About” questions follow each small section of informa- tion, and “Study Questions” are located at the end of each chapter. Questions may relate to simple, factual information, potential applications, or the integration of several concepts. These questions are helpful in alerting a student to points initially overlooked and are useful for student self-evaluation before proceeding to the next section. These features may also serve as a tool for review and test preparation. Brief answers are provided on the Evolve website.
• Brief, adaptable case studies with questions are incor- porated at the end of many chapters and are intended to provide a basis for discussion in a tutorial, an assignment, or an alternative learning mode. It is expected that specific clinical applications may be added by instructors for each professional group.
• Chapter summaries precede the review questions in each chapter.
x P R E FAC E
as such in subsequent chapters, but may be found in the glossary at the back of the book.
• Italics are used to emphasize significant words. • It is assumed that students have studied anatomy and
physiology prior to commencing a pathophysiology course.
• Concise, readable style includes sufficient scientific and medical terminology to help the student acquire a professional vocabulary and appropriate communica- tion skills. An effort has been made to avoid over- whelming the student with a highly technical approach or impeding the learning process in a student who comes with little scientific background.
• The presence of numeric values within textual informa- tion often confuses students and detracts from the basic concepts being presented; therefore, specific numbers are included only when they promote understanding of a principle.
• Suggested diagnostic tests and treatments are not individualized or necessarily complete but are pre- sented generally to assist the student’s application of the pathophysiology. They are also intended to provide students with an awareness of the impact of certain diseases on a client and of possible modifications in the individualized care required. Diagnostic tests increase student cognizance of the extent of data collection and sifting that may be necessary before making a diagnosis, as well as the importance of monitoring the course of a disease or the response to treatment.
• A brief introduction to pharmacology is included in Section I and specific drugs are referred to during the discussion of certain disorders. Drugs are identified by generic name, followed by a trade name. Examples provided in the appropriate chapter are not recom- mendations, but are suggested only as frequently used representatives of a drug classification. A drug index with references to the applicable chapter is located in the appendices.
• Information regarding adverse effects of drugs or other treatment is included when there may be potential problems such as high risk for infection or special precautions required of members of the health care team.
• Every effort has been made to present current informa- tion and concepts simply but accurately. This content provides the practitioner in a health profession with the prerequisite knowledge to recognize and under- stand a client’s problems and the limitations and implications of certain treatment measures; to reduce exacerbating factors; to participate in preventive programs; and to be an effective member of a health care team. The student will develop a knowledge base from which to seek additional information. Individual instructors may emphasize certain aspects or topics, as is most appropriate for students in a specialty area.
Resources
In the textbook: • Selected additional resources are listed in the appen-
dices in Ready Reference 9. • Reference tables are located inside the front book cover.
These comprise common normal values for blood, cerebrospinal fluid, and urine; a pH scale for body fluids; a list of blood clotting factors; and diagnostic tests.
• The chapter introducing pharmacology and therapeu- tics is limited in content, but combined with the brief references to treatments with individual disorders, is intended to complement the pathophysiology. This chapter also introduces a few traditional and non- traditional therapeutic modalities to facilitate the student’s understanding of various therapies and of the impact of diverse treatments on the patient and on care by all members of the health care team. Also included are brief descriptions of a few selected forms of therapy, for example, physiotherapy, in hopes of clarifying the roles of different members of a health care team.
• The appendices at the back of the textbook are intended to promote effective use of study time. They include:
• A brief review of anatomical terms describing body cavities and planes with accompanying illustrations as well as basic body movements
• Selected numerical conversions for temperature, weights, and volumes
• Lists of anatomical terms and combining forms, common abbreviations, and acronyms; because of the broad scope of pathophysiology, a medical dictionary is a useful adjunct for any student in the health-related professions
• A brief description with illustrations of common diagnostic tests such as ultrasound and magnetic resonance imaging
• An example of a medical history, which can be modified to fit the needs of a particular professional group
• A disease index, with a brief description and references to the relevant chapter
• A drug index, identifying the principal action and references to the appropriate chapters
• A list of additional resources; websites consist primarily of health care groups or professional organizations that will provide accurate information and are likely to persist. Additional specific journals and websites are available for individual professions.
• A glossary, including significant terms used to describe diseases as well as key words
• Accompanying this textbook and developed for it, the ancillaries available include: A study guide for students provides learning activities
such as complex test questions, matching exercises, crossword puzzles, diagrams to label, and other assignments
P R E FAC E xi
The interactive Evolve web site includes self-evaluation tools, and can be found at http://evolve.elsevier. com/Hubert/Goulds/
We appreciate the time and effort of reviewers and users of this text, of sales representatives, and of the editors, who have forwarded comments regarding the first four editions. We have attempted to respond to these suggestions while recognizing that comments come from a variety of perspectives, and there is a need to respect
the primary focus of this textbook, space constraints, and student concerns.
We hope that teachers and students will enjoy using this textbook, and that it will stimulate interest in the acquisition of additional knowledge in this dynamic field.
Robert Hubert Karin VanMeter
http://evolve.elsevier.com/Hubert/Goulds/
http://evolve.elsevier.com/Hubert/Goulds/
xii
Acknowledgments
The authors would like to acknowledge and dedicate this edition to the original author, Barbara E. Gould, who passed away. Dr. Gould always kept “student learning” in the forefront as the guideline for writing this book. We also would like to thank all the editorial and produc- tion staff at Elsevier for their support and encouragement. Furthermore, we would like to thank the reviewers for their valuable input.
I would first like to thank my co-author and friend Karin VanMeter. This is our third major project together and it is her continued dedication to education and professionalism that has contributed so much to the overall teamwork and fun working relationship that we enjoy. I would also like to thank Dr. Joan Cunnick and all of the faculty and staff in the microbiology program at Iowa State University for all of your encouragement and support. As with any and all challenges I have tackled in my life, I give my love and thanks to my family—my parents, John and Ann, and my sister Donna, for their unwavering love and support throughout my life. Finally, I lift up my thanks to Jesus Christ, my Lord and Savior, who makes this all possible—to Him be the glory and honor forever.
Robert J. Hubert
My special thanks goes to my co-author Rob Hubert. He has been my friend and collaborator for many years and I am looking forward to many years of working together. Without him all the projects we have done together would have lacked his incredible insight into the topics we have addressed in this new edition. I also would like to thank my mother, Theresia, and my brother, Hermann, and his family for the love, support, and understanding. To my children, Christine and Andrew—thanks for your continu- ous love.
Karin C. VanMeter
xiii
SECTION I Pathophysiology: Background and Overview, 1
CHAPTER 1 Introduction to Pathophysiology, 1 What Is Pathophysiology and Why Study It?, 1
Understanding Health and Disease, 2 Concept and Scope of Pathophysiology, 2 Beginning the Process: A Medical History, 4 New Developments and Trends, 4 Basic Terminology of Pathophysiology, 5
Introduction to Cellular Changes, 8 Terms Used for Common Cellular Adaptations,
8 Cell Damage and Necrosis, 9
CHAPTER 2 Fluid, Electrolyte, and Acid-Base Imbalances, 14
Fluid Imbalance, 15 Review of Concepts and Processes, 15 Fluid Excess: Edema, 16 Fluid Deficit: Dehydration, 20 Third-Spacing: Fluid Deficit and Fluid Excess,
21 Electrolyte Imbalances, 21
Sodium Imbalance, 21 Potassium Imbalance, 24 Calcium Imbalance, 26 Other Electrolytes, 28
Acid-Base Imbalance, 29 Review of Concepts and Processes, 29 Control of Serum pH, 30 Acid-Base Imbalance, 32
Treatment of Imbalances, 36
CHAPTER 3 Introduction to Basic Pharmacology and Other Common Therapies, 40
Pharmacology, 40 Basic Principles, 40 Drug Effects, 41 Administration and Distribution of Drugs, 42 Drug Mechanisms and Receptors, 45 Responses, 46 Drug Classifications and Prescriptions, 46
Traditional Forms of Therapy, 48 Physiotherapy, 48 Occupational Therapy, 48 Speech/Language Therapy, 48 Nutrition/Diet, 48 Registered Massage Therapy, 48
Contents
Osteopathy, 48 Chiropractic, 49
Complementary or Alternative Therapies, 49 Noncontact Therapeutic Touch, 49 Naturopathy, 49 Homeopathy, 49 Herbal Medicine, 49 Aromatherapy, 49 Asian Concepts of Disease and Healing, 49
CHAPTER 4 Pain, 53 Etiology and Sources of Pain, 53 Structures and Pain Pathways, 54 Physiology of Pain and Pain Control, 55 Characteristics of Pain, 57
Signs and Symptoms, 57 Young Children and Pain, 57 Referred Pain, 57 Phantom Pain, 57 Pain Perception and Response, 57
Basic Classifications of Pain, 59 Acute Pain, 59 Chronic Pain, 59 Headache, 59 Central Pain, 60 Neuropathic Pain, 60 Ischemic Pain, 61 Cancer-Related Pain, 61
Pain Control, 61 Methods of Managing Pain, 61 Anesthesia, 62
SECTION II Defense/Protective Mechanisms, 65
CHAPTER 5 Inflammation and Healing, 65 Review of Body Defenses, 66 Review of Normal Capillary Exchange, 67 Physiology of Inflammation, 67
Definition, 67 Causes, 67 Steps of Inflammation, 67
Acute Inflammation, 69 Pathophysiology and General Characteristics,
69 Local Effects, 70 Systemic Effects, 71 Diagnostic Tests, 71 Potential Complications, 72
xiv CO N T E N TS
Chronic Inflammation, 72 Pathophysiology and General
Characteristics, 72 Potential Complications, 73
Treatment of Inflammation, 73 Drugs, 73 First Aid Measures, 75 Other Therapies, 75
Healing, 75 Types of Healing, 75 Healing Process, 76 Factors Affecting Healing, 76 Complications Due to Scar Formation, 78
Example of Inflammation and Healing, 78 Burns, 78 Classifications of Burns, 79
CHAPTER 6 Infection, 88 Review of Microbiology, 89
Microorganisms, 89 Types of Microorganisms, 90 Other Agents of Disease, 99 Resident Flora (Indigenous Normal Flora,
Resident Microbiota), 99 Principles of Infection, 100
Transmission of Infectious Agents, 100 Host Resistance, 101 Virulence and Pathogenicity of
Microorganisms, 102 New Issues Affecting Infections and
Transmission, 102 Control of Transmission and Infection, 103
Physiology of Infection, 105 Onset and Development, 105 Patterns of Infection, 106 Signs and Symptoms of Infection, 106 Methods of Diagnosis, 107 Treatment and Antimicrobial Drugs, 107 Example of Infection: Influenza (Flu), 110
CHAPTER 7 Immunity, 114 Review of the Immune System, 115
Components of the Immune System, 115 Elements of the Immune System, 115 Immune Response, 118 Diagnostic Tests, 119 Process of Acquiring Immunity, 120 Outcome of Infectious Disease, 121 Emerging and Reemerging Infectious Diseases
and Immunity, 121 Bioterrorism, 121
Tissue and Organ Transplant Rejection, 121 Rejection Process, 122 Treatment and Prevention, 122
Hypersensitivity Reactions, 122 Type I: Allergic Reactions, 123 Type II: Cytotoxic Hypersensitivity, 126 Type III: Immune Complex
Hypersensitivity, 127 Type IV: Cell-Mediated or Delayed
Hypersensitivity, 127 Autoimmune Disorders, 128
Mechanism, 128
Example: Systemic Lupus Erythematosus, 128
Immunodeficiency, 131 Causes of Immunodeficiency, 131 Effects of Immunodeficiency, 132 Acquired Immunodeficiency Syndrome, 132
SECTION III Pathophysiology of Body Systems, 142
CHAPTER 8 Skin Disorders, 142 Review of the Skin, 143 Resident Microbial Flora, 144 Skin Lesions, 144
Diagnostic Tests, 146 Skin Inflammatory Disorders, 146
Contact Dermatitis, 146 Urticaria (Hives), 147 Atopic Dermatitis, 147 Psoriasis, 148 Pemphigus, 149 Scleroderma, 149
Skin Infections, 150 Bacterial Infections, 150 Viral Infections, 152 Fungal Infections, 154 Other Infections, 155
Skin Tumors, 157 Malignant Melanoma, 157 Kaposi Sarcoma, 158
CHAPTER 9 Musculoskeletal System Disorders, 161 Review of the Musculoskeletal
System, 162 Bone, 162 Skeletal Muscle, 164 Joints, 166 Diagnostic Tests, 166
Trauma, 167 Fractures, 167
Bone Disorders, 172 Osteoporosis, 172 Rickets and Osteomalacia, 173 Paget Disease (Osteitis Deformans), 173 Osteomyelitis, 173 Abnormal Curvatures of the Spine, 173 Bone Tumors, 174
Disorders of Muscle, Tendons, and Ligaments, 175 Muscular Dystrophy, 175 Primary Fibromyalgia Syndrome, 176
Joint Disorders, 176 Osteoarthritis, 176 Rheumatoid Arthritis, 178 Juvenile Rheumatoid Arthritis, 180 Infectious (Septic) Arthritis, 180 Gout (Gouty Arthritis), 180 Ankylosing Spondylitis, 181 Other Inflammatory Joint Disorders, 182
CHAPTER 10 Blood and Circulatory System Disorders, 184
Review of the Circulatory System and Blood, 185
CO N T E N TS xv
Anatomy, Structures, and Components, 185 Blood Vessels, 185 Blood, 186
Blood Dyscrasias, 195 Anemias, 195 Blood-Clotting Disorders, 204 Myelodysplastic Syndrome, 207
Neoplastic Blood Disorders, 208 Polycythemia, 208 Leukemias, 208
CHAPTER 11 Lymphatic System Disorders, 213 Review of the Lymphatic System, 213
Structures and Function, 213 Composition and Production of Lymph, 215
Lymphatic Disorders, 217 Lymphomas, 217 Multiple Myeloma or Plasma Cell Myeloma,
220 Lymphedema, 220 Elephantiasis (Filariasis), 221 Castleman Disease, 221
CHAPTER 12 Cardiovascular System Disorders, 223 Review of the Cardiovascular System, 224
Heart, 224 Blood Pressure, 229
Heart Disorders, 230 Diagnostic Tests for Cardiovascular
Function, 230 General Treatment Measures for Cardiac
Disorders, 231 Coronary Artery Disease, Ischemic Heart
Disease, or Acute Coronary Syndrome, 233
Cardiac Dysrhythmias (Arrhythmias), 242 Congestive Heart Failure, 245 Young Children With Congestive Heart
Failure, 249 Congenital Heart Defects, 250 Inflammation and Infection in the
Heart, 255 Vascular Disorders, 258
Arterial Disorders, 258 Venous Disorders, 262
Shock, 264
CHAPTER 13 Respiratory System Disorders, 272 Review of Structures of the Respiratory
System, 273 Purpose and General Organization, 273 Structures in the Respiratory System, 273 Ventilation, 275 Gas Exchange, 278 Diagnostic Tests, 280
General Manifestations of Respiratory Disease, 281
Common Treatment Measures for Respiratory Disorders, 283
Infectious Diseases, 283 Upper Respiratory Tract Infections, 283 Lower Respiratory Tract Infections, 286
Obstructive Lung Diseases, 294
Cystic Fibrosis, 294 Lung Cancer, 296 Aspiration, 298 Obstructive Sleep Apnea, 300 Asthma, 300
Chronic Obstructive Pulmonary Disease, 302 Emphysema, 303 Chronic Bronchitis, 307 Bronchiectasis, 307
Restrictive Lung Disorders, 308 Pneumoconioses, 308
Vascular Disorders, 309 Pulmonary Edema, 309 Pulmonary Embolus, 309
Expansion Disorders, 312 Atelectasis, 312 Pleural Effusion, 313 Pneumothorax, 314 Flail Chest, 315 Infant Respiratory Distress Syndrome, 317 Adult or Acute Respiratory Distress
Syndrome, 319 Acute Respiratory Failure, 320
CHAPTER 14 Nervous System Disorders, 325 Review of Nervous System Anatomy and
Physiology, 326 Brain, 326 Spinal Cord, 331 Neurons and Conduction of Impulses, 334 Autonomic Nervous System, 335
General Effects of Neurologic Dysfunction, 338 Local (Focal) Effects, 338 Supratentorial and Infratentorial Lesions, 338 Left and Right Hemispheres, 338 Level of Consciousness, 338 Motor Dysfunction, 339 Sensory Deficits, 339 Visual Loss: Hemianopia, 339 Language Disorders, 340 Seizures, 341 Increased Intracranial Pressure, 341 Herniation, 343 Diagnostic Tests, 344
Acute Neurologic Problems, 344 Brain Tumors, 344 Vascular Disorders, 345 Infections, 350 Brain Injuries, 354 Spinal Cord Injury, 358
Congenital Neurologic Disorders, 363 Hydrocephalus, 363 Spina Bifida, 364 Cerebral Palsy, 365
Seizure Disorders, 367 Chronic Degenerative Disorders, 370
Multiple Sclerosis, 370 Parkinson Disease (Paralysis Agitans), 372 Amyotrophic Lateral Sclerosis, 373 Myasthenia Gravis, 374 Huntington Disease, 374
Dementia, 375
xvi CO N T E N TS
Alzheimer Disease, 375 Other Forms of Dementia, 377
Mental Disorders, 377 Schizophrenia, 378 Depression, 378 Panic Disorders, 379
Spinal Cord Disorder, 380 Herniated Intervertebral Disc, 380
CHAPTER 15 Disorders of the Eyes, Ears, and Other Sensory Organs, 385
Sensory Receptors, 385 The Eye, 386
Review of Structure and Function, 386 Diagnostic Tests, 388 Structural Defects, 388 Infections and Trauma, 389 Glaucoma, 390 Cataracts, 392 Detached Retina, 393 Macular Degeneration, 393
The Ear, 394 Review of Structure and Function, 394 Hearing Loss, 395 Ear Infections, 396 Chronic Disorders of the Ear, 398
CHAPTER 16 Endocrine System Disorders, 400 Review of the Endocrine System, 400 Endocrine Disorders, 403 Insulin and Diabetes Mellitus, 404
Type 1 and Type 2 Diabetes, 404 Parathyroid Hormone and Calcium, 413 Pituitary Hormones, 414
Growth Hormone, 414 Antidiuretic Hormone (Vasopressin), 416 Diabetes Insipidus, 416 Inappropriate Antidiuretic Hormone
Syndrome, 416 Thyroid Disorders, 417
Goiter, 417 Hyperthyroidism (Graves Disease), 418 Hypothyroidism, 420 Diagnostic Tests, 420
Adrenal Glands, 420 Adrenal Medulla, 420 Adrenal Cortex, 421
CHAPTER 17 Digestive System Disorders, 427 Review of the Digestive System, 428
Structures and Their Functions, 428 Neural and Hormonal Controls, 433 Digestion and Absorption, 434
Common Manifestations of Digestive System Disorders, 435 Anorexia, Vomiting, and Bulimia, 435 Diarrhea, 436 Constipation, 437 Fluid and Electrolyte Imbalances, 437 Pain, 438 Malnutrition, 438
Basic Diagnostic Tests, 439 Common Therapies and Prevention, 439 Upper Gastrointestinal Tract Disorders, 441
Disorders of the Oral Cavity, 441 Dysphagia, 446 Esophageal Cancer, 448 Hiatal Hernia, 448 Gastroesophageal Reflux Disease, 449 Gastritis, 449 Peptic Ulcer, 451 Gastric Cancer, 454 Dumping Syndrome, 455 Pyloric Stenosis, 456
Disorders of the Liver and Pancreas, 456 Gallbladder Disorders, 456 Jaundice, 457 Hepatitis, 458 Cirrhosis, 463 Liver Cancer, 467 Acute Pancreatitis, 468 Pancreatic Cancer, 469
Lower Gastrointestinal Tract Disorders, 469 Celiac Disease, 469 Chronic Inflammatory Bowel Disease, 469 Irritable Bowel Syndrome, 473 Appendicitis, 473 Diverticular Disease, 475 Colorectal Cancer, 476 Intestinal Obstruction, 479 Peritonitis, 482
CHAPTER 18 Urinary System Disorders, 488 Review of the Urinary System, 489 Structures and Anatomy, 489
Kidneys, 489 Renal Arteries and Veins, 490
Incontinence and Retention, 493 Diagnostic Tests, 494
Urinalysis, 494 Blood Tests, 495 Other Tests, 496
Diuretic Drugs, 496 Dialysis, 497 Disorders of the Urinary System, 498
Urinary Tract Infections, 498 Inflammatory Disorders, 500
Urinary Tract Obstructions, 503 Urolithiasis (Calculi, or Kidney Stones), 503 Hydronephrosis, 504 Tumors, 505
Vascular Disorders, 505 Nephrosclerosis, 505
Congenital Disorders, 506 Adult Polycystic Kidney, 507 Wilms Tumor (Nephroblastoma), 507
Renal Failure, 507 Acute Renal Failure, 507 Chronic Renal Failure, 509
CHAPTER 19 Reproductive System Disorders, 514 Disorders of the Male Reproductive
System, 515 Review of the Male Reproductive System, 515 Congenital Abnormalities of the Penis, 516 Disorders of the Testes and Scrotum, 516 Inflammation and Infections, 518
CO N T E N TS xvii
Disorders of the Female Reproductive System, 521 Review of the Female Reproductive
System, 521 Structural Abnormalities, 525 Menstrual Disorders, 526 Infections and Inflammation, 527 Benign Tumors, 530 Malignant Tumors, 532
Infertility, 537 Sexually Transmitted Diseases, 538
Bacterial Infections, 538 Viral Infections, 541 Protozoan Infection, 542
SECTION IV Factors Contributing to Pathophysiology, 545
CHAPTER 20 Neoplasms and Cancer, 545 Review of Normal Cells, 546 Benign and Malignant Tumors, 546
Nomenclature, 547 Characteristics of Benign and Malignant
Tumors, 547 Malignant Tumors: Cancer, 547 Examples of Malignant Tumors, 561
Skin Cancer, 561 Ovarian Cancer, 561 Brain Cancer, 561 Cancer Incidences, 563
CHAPTER 21 Congenital and Genetic Disorders, 565 Review of Genetic Control, 565 Congenital Anomalies, 567 Genetic Disorders, 570
Single-Gene Disorders, 570 Chromosomal Disorders, 572 Multifactorial Disorders, 572
Developmental Disorders, 573 Diagnostic Tools, 574 Genetic Technology, 575
Genetic Engineering and Gene Therapy, 575 Genetic Diagnosis and DNA Testing, 575 Proteomic Research and Designer
Drugs, 576 Down Syndrome, 576
CHAPTER 22 Complications of Pregnancy, 579 Embryonic and Fetal Development, 579 Physiologic Changes During Pregnancy, 580
Diagnosis of Pregnancy, 580 Physiologic Changes and Their Implications,
581 Potential Complications of Pregnancy, 583
Ectopic Pregnancy, 583 Preeclampsia and Eclampsia:
Pregnancy-Induced Hypertension, 583 Gestational Diabetes Mellitus, 583 Placental Disorders, 584 Blood Clotting Disorders, 584 Rh Incompatibility, 584 Infection, 585 Adolescent Pregnancy, 586
CHAPTER 23 Complications of Adolescence, 588 Review of Changes During Adolescence, 588 Obesity and Metabolic Syndrome, 589 Musculoskeletal Abnormalities, 590
Kyphosis and Lordosis, 590 Scoliosis, 590 Osteomyelitis, 591 Juvenile Rheumatoid Arthritis, 591 Eating Disorders, 593 Anorexia Nervosa, 593 Bulimia Nervosa, 593
Skin Disorders, 593 Acne Vulgaris, 593
Infection, 594 Infectious Mononucleosis, 594
Disorders Affecting Sexual Development, 595 Chromosomal Disorders, 595 Tumors, 595 Menstrual Abnormalities, 595
CHAPTER 24 Complications of Aging, 597 The Aging Process, 597 Physiological Changes With Aging, 598
Hormonal Changes, 598 Reproductive System Changes, 598 Changes in the Skin and Mucosa, 599 Cardiovascular System Changes, 599 Musculoskeletal System Changes, 600 Respiratory System Changes, 601 Nervous System Changes, 602 Digestive System Changes and Nutrition, 602 Urinary System Changes, 603
Other Factors, 603 Multiple Disorders, 603
Section V Environmental Factors and Pathophysiology, 606
CHAPTER 25 Immobility and Associated Problems, 606 Factors Involving Immobility, 606 Musculoskeletal System Effects, 607 Cutaneous Effects, 607 Cardiovascular System Effects, 608 Respiratory System Effects, 608 Digestive System Effects, 609 Urinary System Effects, 609 Neurologic/Psychological Effects, 609 Effects of Immobility on Children, 610
CHAPTER 26 Stress and Associated Problems, 611 Review of the Stress Response, 611 Stress and Disease, 612
Potential Effects of Prolonged or Severe Stress, 614
Coping With Stress, 615
CHAPTER 27 Substance Abuse and Associated Problems, 617
Terminology, 618 Predisposing Factors, 619 Environmental/Behavioral Risk Factors, 619 Indications/Recognition of Abuse, 620 Potential Complications of Substance Abuse, 620
xviii CO N T E N TS
Overdose, 620 Withdrawal, 621 Effects on Pregnancy, 621 Cardiovascular Problems, 621 Infection, 621 Neurologic/Psychological Effects, 621 Alcohol, 621
Treatment for Substance Abuse, 622
CHAPTER 28 Environmental Hazards and Associated Problems, 624
Chemicals, 625 Heavy Metals, 626 Acids/Bases, 626 Inhalants, 626 Asbestos, 627 Pesticides, 627
Physical Agents, 627 Temperature Hazards, 627 Radiation Hazards, 628 Noise Hazards, 629 Food and Waterborne Hazards, 629
Biologic Agents, 629 Bites and Stings, 629
Appendices, 631
Glossary, 654
Index, 663
1
Introduction to Pathophysiology
S E C T I O N I
Pathophysiology: Background and Overview
C H A P T E R 1
What Is Pathophysiology and Why Study It? Understanding Health and Disease Concept and Scope of Pathophysiology Beginning the Process: A Medical
History New Developments and Trends
Basic Terminology of Pathophysiology The Disease Process Etiology-Causes of Disease Characteristics of Disease Disease Prognosis
Introduction to Cellular Changes
Terms Used for Common Cellular Adaptations
Cell Damage and Necrosis Case Studies Chapter Summary Study Questions
C H A P T E R O U T L I N E
After studying this chapter, the student is expected to:
1. Explain the role of pathophysiology in the diagnosis and treatment of disease.
2. Use the terminology appropriate for pathophysiology. 3. Explain the importance of a patient’s medical history. 4. Describe common cellular adaptations and possible reasons
for the occurrence of each.
5. Identify precancerous cellular changes. 6. List the common causes of cell damage. 7. Describe the common types of cell necrosis and possible
outcomes.
L E A R N I N G O B J E C T I V E S
anaerobic apoptosis autopsy biopsy endogenous exogenous
gangrene homeostasis hypoxia iatrogenic idiopathic inflammation
ischemia lysis lysosomal microorganisms microscopic morphologic
necrosis probability pyroptosis
K E Y T E R M S
What Is Pathophysiology and Why Study It?
Pathophysiology involves the study of functional or physi- ologic changes in the body that result from disease processes. This subject builds on knowledge of the normal structure and function of the human body. Disease
development and the associated changes to normal anatomy or physiology may be obvious or may be hidden with its quiet beginning at the cellular level. As such, pathophysiology includes some aspects of pathology, the laboratory study of cell and tissue changes associated with disease.
2 SECTION I Pathophysiology: Background and Overview
position, and even emotions. Therefore it is impossible to state a single normal value for blood pressure or pulse rate. It is also important to remember that any one indica- tor or lab value must be considered within the total assessment for the individual client.
Likewise, a discussion of a specific disease in a text presents a general description of the typical characteristics of that disease, but some differences in the clinical picture can be expected to occur in a specific individual, based on similar variables.
Concept and Scope of Pathophysiology Pathophysiology requires the use of knowledge of basic anatomy and physiology and is based on a loss of or a change in normal structure and function. This basis also saves relearning many facts! Many disorders affecting a particular system or organ—for example, the liver— display a set of common signs and symptoms directly related to that organ’s normal structure and function. For example, when the liver is damaged, many clotting factors cannot be produced; therefore excessive bleeding results. Jaundice, a yellow color in the skin, is another sign of liver disease, resulting from the liver’s inability to excrete bilirubin. Also, basic pathophysiologic concepts related to the causative factors of a disease, such as the processes of inflammation or infection, are common to many diseases. Inflammation in the liver causes swelling of the tissue and stretching of the liver capsule, resulting in pain, as does inflammation of the kidneys. This cause- and-effect relationship, defined by signs and symptoms, facilitates the study of a specific disease.
To provide a comprehensive overview of disease processes, this text focuses on major diseases. Other disorders are included when appropriate to provide exposure to a broad range of diseases. The principles illustrated by these diseases can then be applied to other conditions encountered in practice. In addition, a general approach is used to describe diseases in which there may be several subtypes. For example, only one type of glomerulonephritis, a kidney disease, is described in the text—acute poststreptococcal glomerulonephritis, which represents the many forms of glomerulonephritis.
Prevention of disease has become a primary focus in health care. The known causes of and factors predisposing to specific diseases are being used in the development of more effective preventive programs, and it is important to continue efforts to detect additional significant factors and gather data to further decrease the incidence of certain diseases. The Centers for Disease Control and Prevention in the United States have a significant role in collection of data about all types of disease and provide evidence- based recommendations for prevention. Prevention includes activities such as maintaining routine vaccination programs and encouraging participation in screening programs such as blood pressure clinics and vision screening (Box 1.2). As more community health programs
Understanding Health and Disease Disease may be defined as a deviation from the normal structure or function of any part, organ, system (or combination of these), or from a state of wellness. The World Health Organization includes physical, mental, and social well-being in its definition of health.
A state of health is difficult to define because the genetic differences among individuals as well as the many varia- tions in life experiences and environmental influences create a variable base. The context in which health is measured is also a consideration. A person who is blind can be in good general health. Injury or surgery may create a temporary impairment in a specific area, but the person’s overall health status is not altered.
Homeostasis is the maintenance of a relatively stable internal environment regardless of external changes. Disease develops when significant changes occur in the body, leading to a state in which homeostasis cannot be maintained without intervention. Under normal condi- tions homeostasis is maintained within the body with regard to factors such as blood pressure, body temperature, and fluid balance. As frequent minor changes occur in the body, the compensation mechanisms respond, and homeostasis is quickly restored. Usually the individual is not aware of these changes or the compensations taking place.
Steps to Health (Box 1.1) are recommended to prevent disease.
When one is defining “normal” limits for health indicators such as blood pressure, pulse, or laboratory data, the values used usually represent an average or a range. These values represent what is expected in a typical individual but are not absolutes. Among normal healthy individuals, the actual values may be adjusted for factors such as age, gender, genetics, environment, and activity level. Well-trained athletes often have a slower pulse or heart rate than the average person. Blood pressure usually increases slightly with age, even in healthy individuals. Also, small daily fluctuations in blood pressure occur as the body responds to minor changes in activity, body
1. Be a nonsmoker and avoid second-hand smoke. 2. Eat 5 to 10 servings of vegetables and fruit a day. Choose
high-fiber, lower-fat foods. If you drink alcohol, limit your intake to one to two drinks a day.
3. Be physically active on a regular basis. This will also help you to maintain a healthy body weight.
4. Protect yourself and your family from the sun. 5. Follow cancer screening guidelines. 6. Visit your doctor or dentist if you notice any change in
your normal state of health. 7. Follow health and safety instructions at home and at work
when using, storing, and disposing of hazardous materials.
BOX 1.1 Seven Steps to Health
CHAPTER 1 Introduction to Pathophysiology 3
the pathophysiology of a disease, comprehension of its manifestations and potential complications, and its treat- ment, usually follow. A solid knowledge base enables health care professionals to meet these increased demands with appropriate information.
Individuals working in health care have found that many new scientific developments have raised ethical, legal, and social issues. For example, the explosion in genetic information and related technologies has raised many ethical concerns (see Chapter 21). In relatively new areas of research such as genetics, discussion and resolu- tion of the legal and ethical issues lag far behind the scientific advances. Health research is most often funded by commercial sources (up to 80% according to some studies), and new breakthrough therapies are often announced before the start of any clinical trials. This causes increased hope and immediate demand for such treatments often as much as a decade before they become available. Understanding the research process and the time required for clinical trials of new therapies is crucial for answering questions about new therapies.
The research process in the health sciences is a lengthy three-stage process that aims to demonstrate both the safety and effectiveness of a new therapy:
• The first stage in this process is often referred to as “basic science” in which researchers work to identify a technology that will limit or prevent the disease process. This stage is carried out in the laboratory and often requires the use of animals or cell cultures.
• The second stage involves a small number of human subjects to determine if the therapy is safe for humans.
• The third stage only takes place if the results of the previous research are positive; the majority of therapies do not make it to this point. In the third stage of research, a large number of patients with the disease or at risk for the disease are enrolled in clinical trials. These are usually double blind studies in which the research subject and the person administering the treatment do not know if the subject is receiving a standard, proven therapy or the therapy being tested. The subject is identified by number only without the particular therapy administered. All results are recorded by the sub- ject’s identification number. The principal investiga- tor is responsible for tracking data collected in trials with many patients, often in several different health centers. The data are then analyzed to determine if the new therapy is more effective than the tradi- tional therapy. In studies of vaccines or other preven- tive measures, data are collected about the occurrence of disease in both the control group and the experimental group to determine if the new measure reduces the incidence of the specific disease.
Research findings that demonstrate merit after this three- stage process are often referred to as “evidence-based research findings.” The research data collected up to this
develop, and with the increase in information available on the Internet, health care workers are becoming more involved in responding to questions from many sources and have an opportunity to promote appropriate preven- tive measures in their communities. A sound knowledge of pathophysiology is the basis for preventive teaching in your profession.
While studying pathophysiology, the student becomes aware of the complexity of many diseases, the difficulties encountered in diagnosis and treatment, and the possible implications arising from a list of signs and symptoms or a prognosis. Sophisticated and expensive diagnostic tests are now available. The availability of these tests, however, also depends on the geographic location of individuals, including their access to large, well-equipped medical facilities. More limited resources may restrict the number of diagnostic tests available to an individual, or a long waiting period may be necessary before testing and treatment are available. When a student understands the pathophysiology, comprehension of the manifestations and potential complications of a disease, and its treatment,
From http://www.iwh.on.ca/wrmb/primary-secondary-and-tertiary-prevention.
Primary Prevention The goal is to protect healthy people from developing a disease or experiencing an injury in the first place. For example: • Education about good nutrition, the importance of
regular exercise, and the dangers of tobacco, alcohol, and other drugs
• Education and legislation about proper seat belt and helmet use
• Regular exams and screening tests to monitor risk factors for illness
• Immunization against infectious disease • Controlling potential hazards at home and in the
workplace
Secondary Prevention These interventions happen after an illness or serious risk factors have already been diagnosed. The goal is to halt or slow the progress of disease (if possible) in its earliest stages; in the case of injury, goals include limiting long-term disability and preventing reinjury. For example: • Telling people to take daily, low-dose aspirin to prevent a
first or second heart attack or stroke • Recommending regular exams and screening tests in
people with known risk factors for illness • Providing suitably modified work for injured workers
Tertiary Prevention This phase focuses on helping people manage complicated, long-term health problems such as diabetes, heart disease, cancer, and chronic musculoskeletal pain. The goals include preventing further physical deterioration and maximizing quality of life. For example: • Cardiac or stroke rehabilitation programs • Chronic pain management programs • Patient support groups
BOX 1.2 Primary, Secondary, and Tertiary Prevention
http://www.iwh.on.ca/wrmb/primary-secondary-and-tertiary-prevention
4 SECTION I Pathophysiology: Background and Overview
Clinical research funding is being directed to identifying treatments as well as preventive measures that are more effective on a cost-per-patient basis.
Many options other than traditional therapies are now available. Treatment by acupuncture or naturopathy may be preferred (see Chapter 3). These options may replace traditional therapies or may be used in conjunction with them. A patient may seek an alternative or complementary mode of treatment to supplement traditional care; thus knowledge of these complementary therapies is often needed. It is also recognized that such therapies and practices should be part of a health history for any client seeking care.
Beginning the Process: A Medical History Many individuals in the health professions will be contributing to, completing, or updating a patient’s medical or health history (see Ready Reference 6 for an example). This information is essential to identify any impact health care activities might have on a patient’s condition, or how a patient’s illness might complicate care. The assessment includes questions on current and prior illnesses, allergies, hospitalizations, and treatment. Current health status is particularly important and should include specific difficulties and any type of therapy or drugs, prescription, nonprescription, and herbal items, including food supplements.
A basic form is usually provided for the patient to fill out, and then it is completed by the health professional asking appropriate follow-up questions to clarify the patient’s current condition and identify any potential problems. Knowledge of pathophysiology is essential to developing useful questions, understanding the implica- tions of this information, and deciding on the necessary precautions or modifications required to prevent complica- tions. For example, a patient with severe respiratory problems or congestive heart failure would have difficulty breathing in a supine position. Reducing stress may be important for a patient with high blood pressure. Pro- phylactic medication may be necessary for some patients to prevent infection or excessive bleeding. In some cases, additional problems or undesirable effects of medications may be detected.
New Developments and Trends Both students and practitioners must constantly update their information and knowledge. Developments in all areas of health care are occurring at a rapid rate primarily due to changes in technologies. New causes of disease and more detail regarding the pathophysiology of a disorder are uncovered, diagnostic tests are improved, and more effective drugs are formulated. Technology has greatly altered many aspects of health care.
Extensive research projects continue in efforts to prevent, control, or cure many disorders. For example,
point are then passed on to regulatory bodies such as the Food and Drug Administration for review. If the therapy is deemed safe and better than the standard therapy used in the past, the data will be approved for use for the specific disease identified in the research protocol.
Evidence-based research does not take into account cost, availability, or social and cultural factors that may influence use and acceptance of a therapy. These factors may be quite significant and affect the physician’s or patient’s acceptance of a therapy.
