Advanced Physiology and Pathophysiology: Essentials for Clinical Practice

Book Preface

Clinicians’ ability to correctly identify disease processes and develop management plans with their patients relies on a deep knowledge of the pathophysiology of disease. This book was developed to meet that clinical need. Physiology seeks to understand the mechanisms of body function, and pathophysiology seeks to understand the mechanisms of altered body function due to pathological states. People, whether patients or clinicians, often fail to appreciate the fine-tuned machine that is the human body until they experience alterations in function that lead to signs and symptoms of disease. Pathophysiology can be viewed with the same lens: Studying the manifestations of body function loss can illuminate the exquisite and intricate functions of our organs that we do not even think about when we are healthy. For every physiological function, there is a pathophysiological consequence when that normal function goes awry. Clinicians-in-training are well positioned to reinforce their knowledge of normal physiological principles when they are presented as the context for disease development, as we have in this book.
In disease states, one or more normal homeostatic mechanisms malfunction, and the organism increasingly relies on compensatory mechanisms to maintain homeostasis. The clinician must know the principles of normal function, the alteration of these functions during disease states, and the benefits and risks of compensatory mechanisms. In addition, one cannot study physiology and pathophysiology in isolation: To understand the complex mechanisms of body function requires application of fundamental principles from chemistry, genetics, cell biology, and other basic sciences.
The data gathered during the clinical encounter include details from the history and physical examination, comprising both subjective and objective findings; results of laboratory studies; results of imaging studies; and other measurements. The clinician must then evaluate these data, consider the differential diagnosis, and formulate a plan. At each step, knowledge of pathophysiology is integral to the process. The aims of this book are to:

• Provide a foundation of core principles of physiology for each system and organ discussed
• Link the pathophysiology of common and selected less common disorders to those core principles
• Alternate discussion of each core principle with the clinical applications, sequencing the content to emphasize the application of those core principles and mechanisms
• Present in-depth life span considerations for each organ and system as developed by geriatric and pediatric content experts who
○ Emphasize developmental aspects of organ functions and their relationships to disorders commonly encountered in infants and children
○ Describe organ and system alterations of normal healthy aging and their relationships to disorders commonly encountered in older adults
• Provide a bridge between pathophysiology and concurrent or later coursework on health history and physical assessment, diagnostic tools and laboratory testing, pharmacology, and nonpharmacologic management strategies

Offer an interdisciplinary perspective on the intricacies of the body’s systems in both a normal and a diseased state, with an author team2 comprising experienced clinicians and educators: nurses and nurse practitioners, physician assistants, dietitians, doctors of pharmacy, physicians, and basic scientists
At the same time, we endeavored to avoid redundancy with topics covered

more extensively in other courses in the graduate curriculum of advanced practitioners. The book does not have a freestanding chapter on the skin, for example. The most common skin disorders have unique presentations that are well described in physical assessment books and clinical lectures on dermatology. We feel that these disorders are best covered in textbooks associated with those topics. Rather than devoting a lengthy chapter to this topic, the mechanisms of selected skin disorders are covered within the context of infectious disease (Chapter 5, Infectious Disease) and immune and leukocyte function (Chapter 6, The Immune System and Leukocyte Function), which are the primary origins of many skin disorders and consistent with our approach of discussing disease in the context of alterations of existing physiological principles and mechanisms.
Similarly, we have selected certain common and uncommon disorders for discussion in the book because of their educational value and the way they illustrate an underlying principle of function. In many curricula, the pathophysiology course spans only one semester, making it impossible to describe an exhaustive list of diseases in detail. While this book explores a wide range of disorders, our approach aims to provide mastery of concepts, vocabulary, and diagnostic evaluation strategies that students can use throughout their remaining clinical semesters to broaden their knowledge of diseases they encounter. Each principle- focused segment ends with Thought Questions to immediately engage the students in reflection and analysis of their level of mastery of that chunk of content. Chapters conclude with Key Points to return students to the big picture of function and dysfunction for the chapter’s main topics. We sincerely hope that this approach produces a resource that students will actually read and keep reading as a companion to their subsequent coursework.