Harrison's Internal Medicine Chapter 12. Pain: Pathophysiology and Management Pain: Pathophysiology and Management: Introduction The task of medicine is to preserve and restore health and to relieve suffering. Understanding pain is essential to both these goals. Because pain is universally understood as a signal of disease, it is the most common symptom that brings a patient to a physician's attention. The function of the pain sensory system is to protect the body and maintain homeostasis. It does this by detecting, localizing, and identifying tissue-damaging processes. Since different diseases produce characteristic patterns of tissue damage, the quality, time course, and location of a. | Chapter 012. Pain Pathophysiology and Management Part 1 Harrison s Internal Medicine Chapter 12. Pain Pathophysiology and Management Pain Pathophysiology and Management Introduction The task of medicine is to preserve and restore health and to relieve suffering. Understanding pain is essential to both these goals. Because pain is universally understood as a signal of disease it is the most common symptom that brings a patient to a physician s attention. The function of the pain sensory system is to protect the body and maintain homeostasis. It does this by detecting localizing and identifying tissue-damaging processes. Since different diseases produce characteristic patterns of tissue damage the quality time course and location of a patient s pain complaint and the location of tenderness provide important diagnostic clues and are used to evaluate the response to treatment. Once this information is obtained it is the obligation of the physician to provide rapid and effective pain relief. The Pain Sensory System Pain is an unpleasant sensation localized to a part of the body. It is often described in terms of a penetrating or tissue-destructive process . stabbing burning twisting tearing squeezing and or of a bodily or emotional reaction . terrifying nauseating sickening . Furthermore any pain of moderate or higher intensity is accompanied by anxiety and the urge to escape or terminate the feeling. These properties illustrate the duality of pain it is both sensation and emotion. When acute pain is characteristically associated with behavioral arousal and a stress response consisting of increased blood pressure heart rate pupil diameter and plasma cortisol levels. In addition local muscle contraction . limb flexion abdominal wall rigidity is often present. Peripheral Mechanisms The Primary Afferent Nociceptor A peripheral nerve consists of the axons of three different types of neurons primary sensory afferents motor neurons and sympathetic postganglionic .
