Visceral Pain and Visceral Somatic Reflexes

The purpose of this chapter is to describe the basic concepts of visceral pain and the referred hyperal-gesia zones on the body surface, in order to enable clinicians to learn the pathophysiologic connection between surface acu-reflex points and visceral pathologic processes.

The homeostasis of a musculoskeletal system is always affected by both mechanical behavior and visceral pathophysiologic processes. Therefore restoration of visceral homeostasis is always a part of restoration of systemic homeostasis.

Visceral pain creates acu-reflex points on the skeletal muscles and joints, which impairs the musculoskeletal balance both in sports and in daily life. It is always necessary to balance visceral physiologic activities when musculoskeletal imbalance is treated.

Visceral pain is common clinically, but only since the 1990s have practitioners been able to improve the understanding of the qualities and mechanisms of this type of pain. Visceral pain is very different from somatic pain. A typical example is cancer pain: its pathologic processes and symptoms may not be correlated, and this complexity makes early diagnosis difficult.

Healthy visceral organs rarely give rise to conscious sensation. When diseased or inflamed, however, they become a source of overwhelming sensation that can monopolize conscious attention. Both visceral and somatic pain produce emotional responses, but visceral pain produces stronger emotional responses that may seem out of proportion to the perceived intensity of the pain. For example, nausea appears more commonly with visceral pain than with somatic pain. Sweating, dyspnea, and other autonomic responses can be extreme with some types of visceral pain, such as angina. Very extensive inflammation (as in ulcerative colitis) or tissue damage (as in gastric perforation) may produce little or no pain in some individuals, while barely discernible disease may produce intolerable pain in others.

Current research reveals these features of visceral pain1:

• It is diffuse and poorly localized.

• It is not linked to visceral injury.

• It is referred to other locations.

• It is accompanied by strong motor and auto-nomic reflexes.

These features are discussed briefly, but the focus of this chapter is on the referred hyperalgesia zones of major viscera.

DIFFUSE SPATIAL LOCALIZATION

A prominent clinical feature of visceral pain is that its clinical localization is unreliable. Visceral pain is deep and diffuse, and often the only localization possible comes with physical examination that stimulates the painful organs. Visceral pain projects sensation to the skeletal muscles on the body surface, but it may be felt in different areas at the same time or may migrate throughout a region even though the pathologic process is confined to a single organ. Unless highly recurrent, visceral pain is not normally perceived as localized to the organ itself; rather, it is perceived as emanating from somatic structures that receive afferent inputs at the same spinal segments as the afferent entry of the relevant viscera, as well as those that receive nonsegmental distribution. For this reason, visceral pain is classically described as being referred, and secondary somatic hyperalgesia, or referred hyperalgesia, may be present at skeletal muscles or joints.

UNCERTAINTY OF VISCERAL PATHOLOGIC PROCESSES

Some disorders, such as chronic pancreatitis, have definable pathology. Others, such as irritable bowel syndrome, noncardiac chest pain, and postcholecy-stectomy syndrome, appear to have no histopathologic basis for the discomfort and pain. The pain may be related to visceral inflammation or scar tissue that is not revealed by laboratory tests.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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