THE ACUTE ABDOMEN Postgrad Med J: first published as 10.1136/pgmj.22.248.149 on 1 June 1946. Downloaded from By H. W. S. WRIGHT. M.S., F.R.C.S. "Our Natures are the Physicians of our Diseases."-Epidemics, VI. 5. "Those Diseases that Medicines do not cure are cured by the Knife."-Aphorisms, VII. 87. HIPPOCRATES. The acute abdomen may be defined as an It is not proposed in this article to describe in intra-abdominal lesion which, apart from appro- detail abdominal conditions which are adequately priate treatment, immediately threatens the life of dealt with in all standard textbooks, but rather to a patient. In England, with a population of analyse their symptomatology and its mechanism in nearly 42 millions, considerably more than I2,000 such a way that a clinical pattern emerges quite people die annually from what is called "an acute simply from a mosaic of apparently unrelated abdomen." The annual crude death4ate from symptoms, and to show that the treatment sug- appendicitis is 62 per million, and from hernia gested is a logical sequence to pathological findings. and intestinal obstruction IO9 per million. In greater The symptoms and signs which give evidence of London, with a population of nearly nine million an acute intra-abdominal lesion are as a rule few persons, at least Io,ooo per annum are -admitted and simple. They are pain, superficial and deep with a diagnosis which implies a major abdominal tenderness, rigidity, and vomiting. With these are catastrophe. Because they are incomplete, these associated the general effects of the lesion on the figures underestimate the magnitude of a problem whole organism, such as temperature changes, and which claims a large and important share of every alterations both absolute and relative, in the surgeon's time and attention. It would be sur- composition of the blood and urine. The integra- prising if such a group of cases, with so much in tion of these signs and symptoms into familiar common, did not have an embryological and clinical patterns usually enables a diagnosis to be Protected by copyright. biological background which deserves understand- made with rapidity and certainty, often on the ing and consideration. telephone; but in many cases the most meticulously When, in the course of biological evolution, the careful history, precise examination, and the nicest mesoderm became differentiated as a separate cell judgment are necessary before reliable conclusions mass which later split to form a body cavity or can be reached, and in order to do this some coelom, the formation of this cavity marked a knowledge of the nature and mechanism of critical stage pregnant with possibilities. The symptom production is necessary. organs inside the cavity were separated from the The pain of abdominal disease is of two kinds, exterior for their specialised functions of digestion, visceral and somatic, and they can frequently be absorption, and respiration. Such an advance distinguished from each other by the description removed many obstacles to increase both in size given by an intelligent patient, and sometimes by and variety, and determined the possibilities of the patient's appearance. Visceral pain arises coelomate forms. But the differentiation of an directly from pathological changes in the involved http://pmj.bmj.com/ intestinal canal within a serous cavity implies the viscus or its mesentery and vascular connections, provision of a vascular system for its own nourish- and somatic pain arises from the parietes as the ment and the transport of metabolites, a lymphatic result of secondary and coincidental changes. The system for absorption and protection, and a classic example. of visceral pain is that due to nervous and endocrine system for co-ordination coronary thrombosis, to renal or intestinal colic. and control. With this increased complexity there It is tearing, crushing, or bursting in quality, often is necessarily an increased danger of breakdowns severe enough to cause vomiting, rapid pulse, and fraught with disastrous and far-reaching conse- some degree of collapse; the patient may roll about on September 23, 2021 by guest. quences. The existence of a coelom, in fact, or double himself up in what he may well call implies the probability of the acute abdomen. agony. In the case of colic it rises to a crescendo It is easy to see that organs, such as thc appendix and then diminishes, only to recur again. This and the gallbladder, which are developed as blind type of pain is characteristic in that it can be diverticulae from the midgut, must always be abolished by section of the appropriate sympathetic liable to obstruction and subsequent infection, a pathways. It is usually imprecisely localised but series of changes so aptly called "the hollow viscus has an area of reference which depends on the pathology." Inherent in the localising and pro- embryology of the implicated viscus. Very often tective functions of the peritoneum and omentum the patient will say the pain is inside the abdomen. is the possibility of adhesions and obstruction, This type of pain is most easily distinguished at and the presence of lymphatic tissue thinly covered the onset of the attack before the adjacent parietal with muscle and peritoneum makes occasional peritoneum is involved, and other protective swelling, necrosis, and perforation a certainty. reflexes are established. It is frequently but not POST-GRADUATE MEDICAL JOURNAL June, 1946 Postgrad Med J: first published as 10.1136/pgmj.22.248.149 on 1 June 1946. Downloaded from invariably associated with rigidity and deep pheral end of a novocaine-blocked sensory nerve. tenderness. For instance, the pain of renal colic Since it arises some time after the stimuli, which is sometimes accompanied by rigidity and tender- probably do not reach the cord, have ceased, it is ness over an area wide enough to be suggestive of unlikely that it has its origin in the cord itself.* a perforation, whereas the pain of intestinal colic Muscular rigidity is associated with both parietal frequently is not, and if rigidity and tenderness are and visceral pain. It may affect part of a muscle present, as a rule thev disappear soon after the colic whose total nerve supply comes from several ceases. The reason for the often vague localisation segmental nerves, thus producing a so-called of visceral pain is that-the afferent nerves from phantom tumour, and it may persist for some days viscera traverse the ganglia of the autonomic after the pain has ceased. This suggests that it system to the posterior nerve roots which are may be due to a "facilitated reflex" and that a arranged segmentally, but the subjective aspect of stimulus qualitatively below the threshold of pain localisation takes place in the brain where pain is may continue to produce rigidity when the pain registered in terms of quality and position. Neither has ceased. This persistence is not uncommon in of these latter attributes are constant, and vary inflammation of the gallbladder or appendix, and from individual to individual. because of this, a surgeon on opening the abdomen, For instance, the early pain in a typical attack may sometimes find much less evidence of acute of acute appendicitis is usually felt around the inflammation than he had previously led himself umbilicus. This might well be expected as the to expect. appendix is part of a mnedially developed midgut, The mechanism of deep tenderness is much more but the pain is often described by the patient as difficult to understand. It is as a rule coincident arising in the epigastric region, and occasionally in time both with the pain and rigidity. It elsewhere. An analogy may perhaps make these probably arises in the muscle itself because, as individual differences comprehensible, if not reason- Lewis has shown experimentally, muscle is tender Protected by copyright. able. The quality of tones registered in a photo- after contracting for two or three minutes, and graph varies with the composition of the film, so after spasm of longer duration muscular tenderness also do the spatial relationships vary with its may persist for some time. This tenderness is contour. Seen in this way it does not seem probably related to partial ischaemia, but whatever .unlikely that different individuals will describe its cause everyone is familiar with the stiffness the quality and position of their visceral sensations and tenderness which follow prolonged unac- differently. That they do so is a fact of observation customed exercise. It is however certain that which has to be constantly bome in mind when ischaemia does not represent the whole story, since assessing the value of a patient's statements. deep tenderness in the testicle may be produced The other type of pain which occurs in acute either by renal colic or by the intraligamentary abdominal disease arises from inflammation of the injection of saline. neighbouring peritoneum, or reflex irritation of the Pain, rigidity, deep tenderness, and hyperaes- overlying muscles. It is constant in position, thesia then are the cardinal symptoms of acute unvarying in quality, and in the nature of buming abdominal pathology. It is wise to remember that http://pmj.bmj.com/ or aching. When severe, it is difficult to dis- the severer types of visceral and somatic pain may tinguish from any other severe pain except that it be indistinguishable, and that either or both is more precisely localised. It is nearly always together are often associated with their reflex associated with rigidity and deep tendemess. Since effects, rigidity, deep tenderness, and hyperaes- it arises from the parietes, the nerves of which thesia. These last three may also be caused by pass through the appropriate posterior roots- and inflammation in the muscles and ligaments of the rela- can be retain their original segmental arrangement appropriate segments and exactly repro- on September 23, 2021 by guest.