Another remarkable characteristic of pain is the strong feeling or affect with which it is endowed, nearly always unpleasant. Since pain embodies this element, psychologic conditions assume great importance in all persistent painful states. It is of interest that despite this strong affective aspect of pain, it is difficult to recall precisely, or to reexperience from memory, a previously experienced acute pain. Also, the patient’s tolerance of pain and capacity to experience it without verbalization are influenced by culture and personality. Some individuals—by virtue of training, habit, or phlegmatic temperament—remain stoic in the face of pain, and others react in an opposite fashion. In other words, there are inherent variations among individuals that determine the limbic system’s response to pain and their expression of it. In this regard, it is important to emphasize that pain may be the presenting or predominant symptom in a depressive illness (Chap. 48).
Price reviews this subject of the affective dimension of pain in detail, but it must be acknowledged that the models offered are largely theoretical. It is noteworthy, however, that on functional imaging studies, regions of the cerebrum that are activated by experimentally induced physical pain overlap to a limited degree with those for the experience of emotional pain, as reported by Wager and colleagues.
Finally, a comment should be made about the devastating behavioral effects of chronic pain. To quote from Ambroïse Paré, a sixteenth-century French surgeon, “There is nothing that abateth so much the strength as paine.” Continuous pain increases irritability and fatigue, disturbs sleep, and impairs appetite. Patients in pain may seem irrational about their illness and may make unreasonable demands on family and physician. Characteristic is an unwillingness to engage in or continue any activity that might enhance their pain. They withdraw from the main current of daily affairs as their thoughts and speech come to be dominated by the pain. Once a person is subjected to the tyranny of chronic pain, depressive symptoms are practically always added. A person’s entire identity may be dominated by the mixture of pain and depression (l’homme doloureux). Determining the cause and effect is usually a futile exercise.
One learns quickly that not all pain is the consequence of serious disease. Every day, healthy persons of all ages have pains that must be taken as part of normal sensory experience. To mention a few, there are the “growing pains” of presumed bone and joint origin of children; the momentary shock-like pains over an eye or in the temporal or occipital regions (“ice-pick” pain), which strike with such suddenness as to raise the suspicion of a ruptured intracranial aneurysm; inexplicable split-second jabs of pain elsewhere; the more persistent ache in the shoulder, hip, or extremity that subsides spontaneously or in response to a change in position; the fluctuant precordial discomfort of gastrointestinal origin, which conjures up fear of cardiac disease; and the breathtaking “stitch in the side” caused by intercostal or diaphragmatic cramp during exercise. These “normal pains,” as they may be called, tend to be brief and to depart as obscurely as they came. Such pains come to notice only when elicited by an inquiring physician or when experienced by a patient given to excessive worry and introspection. They must be distinguished from the pain of disease.
Whenever pain—by its intensity, duration, and the circumstances of its occurrence—appears to be abnormal or when it constitutes the chief complaint or one of the principal symptoms, the physician must attempt to reach a tentative decision as to its mechanism and cause. This is accomplished by a thorough interrogation of the patient, with the physician carefully seeking out the main characteristics of the pain in terms of the following:
Mode and time of onset
Associated features, e.g., nausea, muscle spasm