CHAPTER I PAIN (Part 1)

CHAPTER I PAIN GENERAL CONSIDERATIONS BEFORE we begin to study the cause or the cure of any pain, we need to convince ourselves that it really exists. Not only in the cases of deliberate deception or malingering, but in dealing with perfectly honest people, we are liable to error. Many persons, especially of the less educated classes, do not distinguish between pain and the other varieties of discomfort, such as itching ora sense of pressure. Many patients who say at first that they have a headache or a stomachache may be brought, by a little questioning, to recognize that they are referring to a sense of weight, constriction, or vague discomfort, rather than to pain in the narrower sense. As evidences of pain we are accustomed to scrutinize: (a) The facial expression and bodily movements. (6) The account of some onlooker, such as a nurse or relative. (c) The results, such as emaciation or muscular weakness, often produced by long-continued suffering. (d) The blood-pressure. When a patient’s face is contorted and his body writhes, stiffens, or doubles up, we can have no doubt that he is suffering, unless we believe him an impostor, but obviously these evidences of pain may be easily simulated or exaggerated. It is in such cases that we need the testimony of some third person who can watch the patient at a time when he supposes himself to be alone. Many patients who do not intend to deceive us show far greater evidences of suffering when a doctor, a nurse, or a friend is near at hand than when they believe they are unobserved. This is partly due to the fact that a perfectly genuine though distinctly mild lesion is very much more pain- ful to the patient when his self-pity is aroused by the presence of a sym- pathetic onlooker. When a patient who bears the ordinary marks of blooming health states that he has been suffering excruciating pain for many months, the lack of any of the ordinary evidences of suffering naturally and EZ PAIN 25 properly make us take his statement with a grain of salt. Chronic suffering is pretty sure to leave its mark on the face and body. In cases of suspected malingering, when an individual states that a certain motion or a certain pressure upon a supposedly tender point causes great suffering, we may control his statement to a certain extent by measuring the peripheral blood-pressure at the time. Severe pain almost always causes a notable rise in blood-pressure, and if we find noth- ing of the kind, we may rightly conclude that if pain is present, it is probably not intense. DEGREE OF PAIN T have long been accustomed to compare, as a matter of routine and in every case, the extent and quickness of the knee-jerks with the patient's statement regarding his own suffering. I have found that those who describe all their troubles as “terrible,” “awful,” “fearful,” and the like, are very apt to have lively knee-jerks, and that those who are more moderate in their expressions have usually less active reflexes. It seems quite probable that there is a parallelism here between reflex sensibility and sensitiveness to pain. Those who respond to a given stimulus by an exaggerated knee-jerk might well be expected to respond toa given cause of pain by an exaggerated complaint. So it has seemed to me as a result of many observations, and I have come to believe that people are more likely to be oversensitive and to exaggerate their suffer- ings when the knee-jerks are unusually lively. This is, of course, a very rough and uncertain method of measuring pain, and would perhaps be more truly described as an attempt to meas- ure the severity of the cause of pain, rather than of the pain itself. We are greatly in need of some more accurate method of estimating how much people suffer. For the present, we have to judge largely by such uncertain evidences as were mentioned in the last section—facial expres- sion, bodily movement, the accounts of onlookers, and the evidences of such physical changes as pain might produce. In addition to these we get a certain amount of information by asking: “Does the pain prevent you from working?” “Does it prevent sleep?” * “Does it take away appetite, the capacity for movement and en- joyment in the ordinary functions of life?” We know that certain races—for example, the Chinese—are much less sensitive than others to pain in that they exhibit far less evidence of “shock” after a bullet wound or a disembowelment. We can only guess at the sensory side of this phenomenon, but the absence of the ordinary organic effects produced by the same injury in a Caucasian gives us some 26 DIFFERENTIAL DIAGNOSIS ground for believing that the suffering is proportionately small. In all probability there are similar differences between individuals of the same race. Though women are generally believed to be more highly organized and more sensitive than men, it is a well-known fact that they bear pain, especially prolonged pain, better than men. I have never heard any plausible explanation of this fact. TYPES OF PAIN Most of the adjectives which are attached to the complaints of pa- tients, either by themselves or in the text-book description, give us no in- formation of value because they are not regularly associated with any one disease. Boring pains, tearing pains, and knife-like pains do not characterize any particular disease. Nevertheless, there are a few dis- tinctions of importance. Pains that recur rhythmically, or at regular intervals, working up gradually to a climax each time, and then disappearing suddenly or gradually, are often associated with hyperperistalsis within some hollow tube, such as the intestine, the ureter, the bile-ducts, or the uterus. To such pains the name of “colic” is traditionally attached, though it is often used much more vaguely to denote any type of severe and sudden pain in the abdomen. Throbbing pains, increased momentarily with each beat of the heart, are characteristic of vascular hyperemia, such as occurs about the roots of an inflamed tooth. In connection with vasomotor headaches and in dysmenorrhea we occasionally see the same phenomenon. Pain with a sense of constriction is of great diagnostic value when it occurs in the precordial region, pointing, as it does, in the great majority of cases, to angina pectoris as its cause. Other diseases producing pain in this region are rarely, if ever, accompanied by this sense of constriction, which the patients often express in very vivid phrases, e. g., “as if I were squeezed in a vise,” or “as if some one gripped my heart in his hand.” Thoracic or abdominal pain increased or produced by exertion and promptly relieved by rest is almost alivays due to the cause just men- tioned—angina. Many pains supposed by the patient to be due to in- digestion, to rheumatism, or to neuralgia may thus be recognized as anginoid. Pain that shoots and darts, especially if it follows the course of some nerve-trunk, usually turns out to be neuralgic. In many cases such a pain is associated with prickling, burning, numbness, or other pares- thesias. PAIN 27 RELATION OF PAIN TO OTHER FACTS A careful history of the bearing of various factors in the patient's habits and environments upon the occurrence or the severity of pain is of prime importance in diagnosis. Among the elements to be taken account of are the relation of pain to: (a) The time of day. (6) The position of the body. (©) The taking of food. (d) The effect of motion involving the painful part, or of jolt- ing of the entire body. (e) The effect of emotional excitement. (f) The effect of occupation. (g) The effect of season and the weather. (hk) The mode of relief—e. g., by heat, cold, food, vomiting, medicine, rest, occupation. Neurasthenic headaches and the pains of chronic joint troubles are apt to be worse in the morning and to improve as the day goes on. Any pain associated with fever and infection is likely to be worse in the even- ing, when the temperature is at its highest. Pains affected by position are especially those due to diseases of the joints and muscles, such as lumbago, sacro-iliac strain, all the types of arthritis, stiff neck, and the like. Almost all varieties of pelvic disease are worse when the patient is on her feet, as the position is likely to involve some pressure or dragging upon painful points. For the same reason the surgical affections of the kidney and all diseases which in- yolye splenic enlargement are usually more painful when the upright position is assumed. Occasionally a headache is distinctly improved or aggravated when the patient lies down. The distress accompanying uncompensated cardiac disease is always aggravated by recumbency. Most muscular pains are aggravated by the use of the muscle; hence the presence of such an aggravation may help us to distinguish muscular pains from those of different origin. It must be remembered, however, that in some cases the pains of neuritis are increased by use of the part, even when no muscular lesion is discoverable. The motion of coughing brings great distress in pleurisy, pneumonia, and all discases involving d not only by the intercostal muscles. Anginoid pains are increas motion, but by any other cause which raises blood-pressure (gastric digestion, mental exertion, or excitement). On the other hand, some pains are made worse by rest; for example, all types of habit pains, to which I shall refer more in detail in the next section. The pains of chronic joint troubles are worse immediately after rest, when the patient attempts to move his stiffened joints. 28 DIFFERENTIAL DIAGNOSIS The effect of jolting, as in riding on a rough road or a rough-gaited horse, is traditionally associated with an increase of the distress pro- duced by stone in any part of the urinary tract. Doubtless this is a true observation, but there are many exceptions to the rule. Aggravation of any pain by the taking of food properly inclines us to believe that the pain is produced in the stomach (gastritis, gastric ulcer, gastric cancer, gastric neurosis). Many intestinal pains, however, are likewise produced or increased when food enters the stomach. Thus the sufferings due to enteritis and to chronic intestinal obstruc- tion are often much worse immediately after a meal. It appears to be true, moreover, that pain due to gall-stones, and even to chronic appendicitis, may be set agoing by the presence of food in the stomach. I have already referred to the excitement of anginoid pain through the rise of blood-pressure produced by the act of digestion. Possibly an accompanying gaseous distention may help to call out the attack. Relief of pain by food is characteristic of peptic ulcer and of hyper- chlorhydria, as well as of the vaguer gnawings due to hunger. Many types of muscular, articular, and neural pains are subject to aggravation as the result of various meteoric conditions, of which we understand all too little. It cannot be questioned, I think, that the muscular pains involved in lumbago and stiff neck are more apt to be present in damp, rainy weather, such as occurs in the spring and fall, than in dry heat or dry cold. The persons who can foretell a storm by the disagreeable sensations in the neighborhood of diseased joints are very numerous, but I have never been able to associate this form of prophecy with any one type of disease. I am also convinced that the approach of a thunder-storm may precipitate a headache not only in those predisposed to migraine, but in other sensitive persons. Whether this is due to barometric, to electric, or to quite unknown conditions Iam unable to say. Many of my patients have noticed that their headaches are more apt to occur on especially bright, bracing days, when the air is unusually clear. Relief by vomiting does not prove that the disease is of gastric origin. Intestinal pain, biliary colic, renal colic, and the sufferings of duodenal ulcer may also be relieved by emesis. Relief by heat or by cold cannot be predicted for any variety of pains. The same disease in different individuals may be assuaged now by the one now by the other agencies. It is wholly a matter of experi- mentation. But in my experience most of the pains which cold relieves are more completely and more permanently abated by heat. PAIN 29 HABIT PAINS The term is a misleading one, and needs more explanation than the fact. The genesis of the latter may be described as follows: (a) Some exciting, terrifying, or mortifying event draws the patient’s attention to a certain part of his body—the cardiac region or the pharynx, for example. Then— (b) As the microscope discovers bodies invisible to the unaided eye, so the patient’s focused and concentrated attention discovers sensa- tions due probably to some of the physiologic changes occurring normally in the part to which attention has, unfortunately, been directed. These changes go on normally without producing any sensation noted by the brain. But when the brain is sensitized, especially in relation to the part attended to, even the heart-beat may be felt as painful, or the normal blood, lymph, and nerve-currents of the pharynx may be magnified into painful events. (c) The “set” of attention produced by habit keeps the brain “on edge,” keyed up to perceive the slightest glimmer of sensation, such as we ordinarily disregard. (@ Finally, some actual disturbance of the function of the part may follow this abnormal interference of consciousness in activities which should be subconscious. The heart-beat becomes irregular; the pharynx secretes abnormally. This redoubles, of course, the patient’s alarmed concentration upon the part, and so a vicious circle is established. Such a circle is broken, and the diagnosis of habit pain confirmed when we succeed in switching off the patient’s attention upon other subjects—and thus making him forget, at any rate for a time, his habitual sufferings. THEORIES REGARDING THE PRODUCTION OF PAIN I wish to refer briefly to the beliefs of McKenzie and Head, also to those of J. Pal, regarding the means whereby pain is produced under certain conditions. To James McKenzie! and to Henry Head? we owe the elaboration of a theory whereby pain and cutaneous hyperesthesia are viewed as associated manifestations of morbid irritability in one or another group of spinal ganglion-cells. According to their theory, this irritability is due to impulses transmitted from a diseased organ, which, though not itself the seat of pain, yet causes in the corresponding spinal segment 1 James McKenzie, Symptoms and their Interpretation, Shaw and Sons, London, 1909. 2Henry Head, On Disturbances of Sensation, Brain, 1893, vol. xvi, p. 15 also in subsequent numbers, 1894, 1896, T9900, etc. 3° DIFFERENTIAL DIAGNOSIS a disturbance which is transferred thence to the periphery of the body, and there recognized by the individual as pain in a place often far distant from the organ diseased. Thus these writers account for the umbilical pain experienced in intestinal obstruction, no matter where the stoppage occurs, by supposing that all parts of the intestine are represented in the cord by the same spinal segment, and that the umbilical region is the seat of centrifugal impulses from that center, resulting in cutaneous hyperesthesia, as well as pain. The best confirmation and exemplification of this theory are seen in the so-called radiations of the pain known as angina, pectoris, and in the similar radiations from the site of biliary colic. It is difficult to account for the arm pains of angina and the shoulder pains of gall-stone disease on any other hypothesis, and if all other types of pain could be traced with similar accuracy to a spinal segment, rather than to an organ directly underlying the painful spot, the theory of McKenzie and Head would deserve our unqualified assent. In point of fact, however, the two examples given above are almost the only ones in which the theory is clearly verifiable. The pain of appendicitis, of pleurisy, most kid- ney pains and splenic pains do not well accord with the tneory, and the zones of cutaneous hyperesthesia which are essential to the con- firmation of their theory have seldom been found by other observers. In spite of my profound respect for the originators of this theory, I have been unable to apply it successfully in clinical work, except in the two diseases just referred to, and in the localization of spinal lesions. More useful, on the whole, is the book on Gefasskrisen, in which Pal elaborates, upon the basis of careful observation, both at the bed- side and at the dead-house, a theory of the origin, not of all pains, but of certain paroxysmal types of suffering associated especially with the vessels of the brain, the heart, and the kidney, but to a lesser extent with those of the intestine and of the extremities. He supposes that arterial spasm (favored and prepared for by arteriosclerosis, by uremia, by lead-poison- ing, and by the nerve lesions of tabes) is the cause of a large group of pains, paralyses, and other functional disturbances which had never before been brought together under any single explanation. Taking lead-poison- ing as an impressive example of the theory, he points out that we have here a notable rise of blood-pressure, associated sometimes with cerebral crises (headache, convulsions, coma), often with abdominal crises (lead colic), and occasionally with anginoid seizures. In arteriosclerosis we have likewise cerebral, abdominal, and cardiac crises, and, in addi- 1J. Pal, Gefasskrisen, Leipzig, 1905. PAIN 3t tion to these, well-marked peripheral crises (intermittent claudication). In uremic and eclamptic poisoning we have likewise cerebral and ab- dominal crises. In tabes dorsalis the abdominal cri familiar. In all these affections postmortem examination may demonstrate that there is no gross lesion, such as cerebral hemorrhage or throm- bosis, coronary occlusion, or blocking of a peripheral artery. Indeed, the arteries