Diseases of the Alimentary System

ALIMENTARY SYSTEM, DISEASES OF THE. Great advance in our knowledge of these diseases during recent years may be attributed chiefly to three factors : ) the opportunities of observation afforded by the performance of surgical operations on the abdomen—the study, as it has been termed, of "the pathol ogy of the living"; (2) an improved X-ray technique ; (3) the introduction of biochemical tests for estimating the "physiological efficiency" of important organs such as the stomach, pancreas, and liver. The information gained by these methods has rendered diagnosis of diseases of the alimentary system more precise (see DIAGNOSIS), but has not proportionately advanced their treatment except by surgical operation.

The Oesophagus.

In no section of the alimentary canal have the X-rays (see X-RAYS) proved to be of greater value in diag nosis than in the oesophagus, and the indications they afford have been rendered more precise by direct inspection of the interior of the gullet by the oesophagoscope. The commonest symptom of disease of the oesophagus is difficulty in swallowing (dysphagia) which results from its obstruction. This is most frequently due to cancer, which chiefly occurs in men and is generally situated at the lower end of the tube where it joins the stomach, though it may also occur at the entrance or at an intermediate point opposite the bifurcation of the trachea. Functional obstruction is much rarer and occurs at the lower end, being due either to a spasm of the muscular sphincter at the entrance to the stomach, or to a failure of the muscular ring to relax as the food passes on (so-called "achalasia") . However brought about, the obstruction leads eventually to "idiopathic dilatation" of the oesophagus (oesophagectasia) .

This variety of obstruction occurs in women perhaps oftener than in men and is compatible with comparatively good health. It is treated by dilatation with bougies passed through the mouth or, sometimes, by stretching the lower end of the oesophagus by means of instruments introduced through an incision in the stomach. Diverticula, or pouches, are a still rarer cause of ob struction which can be recognized by X-ray examination.

The Stomach.

Cancer still remains the most serious disease of the stomach (see CANCER) and has increased rather than di minished in frequency in the last few years. It is commonest in men in the fifth and sixth decades of life and may be situated at the pylorus, which is the most frequent site, at the cardiac orifice (rarest), or in the body of the organ. Its early diagnosis, in time to afford a chance of cure by operation, is still a matter of difficulty, but improved X-ray technique is helping to solve the problem. The so-called "leather-bottle stomach" (linitis plastica) is now known to be generally due to diffuse cancerous infiltration.

Our knowledge of the next most serious disease of the stomach (gastric ulcer) has been rendered much more precise in recent years mainly by the work of the surgeons. Ulcer occurs in two forms, the acute and the chronic. Acute ulcers are usually mul tiple and may appear in the course of any septic infection, but when developing "idiopathically" they are most often met with in young women ; chronic ulcers, on the other hand, are commoner in men of middle age, and are nearly always solitary. Acute ulcers are apt to perforate and may also cause profuse haemor rhage ; chronic ulcers rarely perforate ; but they, too, often bleed. The older statistics according to which "gastric ulcer" was chiefly a disease of women, were the result of including all the cases; the term as now usually employed refers to the chronic ulcer, chiefly a disease of men. The acute ulcer of young women is less often met with in recent years than it was formerly. The chief symptoms of the acute variety of ulcer are pain immediately after taking food, Vomiting and, not uncom monly, haematemesis, with comparatively little disturbance of the general health. The chronic ulcer causes pain which occurs very punctually from one to two hours after meals while vomit ing and haematemesis are less often met with. Some degrees of weakness, wasting, and anaemia are apt to be present. The symptoms of the chronic ulcer recur in attacks lasting a few weeks with long periods of more or less complete freedom from discomfort between.

When the chronic ulcer is situated at the pylorus it leads to gradual occlusion of the latter with consequent dilatation of the stomach; when situated in the body of the organ it may bring about an "hour-glass" constriction. The most serious change which a chronic ulcer can undergo, however, is its conversion into a cancer. The frequency with which such a transformation occurs is disputed, but that there is a real risk of it, all surgeons are now agreed, and its possibility is one of the chief arguments for the surgical treatment of all cases of chronic ulcer. On the other hand there is no place for surgery in the treatment of the acute ulcer unless perforation has taken place. Haemorrhage from an acute ulcer is rarely fatal and is now never treated by operation ; the question of operation in bleeding from a chronic ulcer is still sub judice, but opinion is moving in favour of it, transfusion being performed first if necessary.

Chronic ulcer of the duodenum is closely akin to chronic gastric ulcer. Over 8o% of the cases are in males. As in gastric ulcer the symptoms occur in attacks lasting a few weeks and often sepa rated by long intervals of complete freedom. Pain is the chief symptom and tends to come on when the stomach is empty and to be relieved by taking more food—hence the term "hunger pain" applied to it. Vomiting is very rare and the chief com plications are perforation, which is much commoner than in chronic gastric ulcer, and haemorrhage which may lead both to vomiting of blood and its passage from the bowel (rnelaena). The ulcer is usually situated on the anterior wall of the first part of the duodenum and is apt, after it has been present for a long time, to lead to narrowing of the outlet of the stomach. On the other hand chronic duodenal ulcers—unlike gastric—never become malignant.

Gastric and duodenal ulcers (q.v.) are sometimes spoken of together as "peptic ulcers," and our knowledge of the patho genesis of the peptic ulcer has advanced considerably, as the result of the work of Bolton in Great Britain and of Rosenow in America. The first stage in the development of an ulcer is the formation of a small area of necrosis in the mucosa in conse quence of the lodgment in it of pathogenic streptococci. These organisms appear to reach the stomach or duodenum by the blood stream, either being swallowed or entering the blood from a focus of sepsis in the teeth, tonsils, appendix, gall-bladder, or some other source. According to Rosenow, the ulcer-forming organisms exhibit an "elective" affinity for the gastric mucous membrane while others may show a similar affinity for, say, the gall-bladder. Be this as it may, the result of the formation of an area of necrosis in the mucous membrane is that auto-digestion of the dead tissue takes place and a small acute ulcer forms. Most of these heal quickly, but in certain circumstances—for example abnormally high gastric acidity—one of them fails to heal, grad ually enlarges, and becomes a chronic ulcer. The remaining or ganic affection of the stomach (gastritis) is of less frequent occurrence than was formerly supposed.

The functional disorders of the stomach which are responsible for a great deal of what is commonly called "dyspepsia" are still but ill-understood although, by means of X-ray examinations and the use of "fractional" test meals, light is gradually being thrown upon them. Two chief types of functional disorder occur, secretory and motor, and each of these may be affected in the direction either of excess or defect.

Secretory Disorders.

Itis now known that the gastric juice as secreted has an acidity of about o.5%, but that this is re duced to the optimum acidity for digestion (0.2%) by dilution and neutralization in the stomach, and that the most powerful factor in neutralization is the regurgitation of duodenal contents through the pylorus. An excessive acidity of the stomach con tents therefore ("acid dyspepsia," hyperchlorhydria) may be due either to over-production of gastric juice or to deficiency of neutralization, or to both, and can no longer be regarded as a definite "clinical entity." Deficient acidity on the other hand (hypochlorhydria, achylia) may be due either to defective se cretion or to excessive neutralization. The secretion of gastric juice is controlled partly by the vagus nerve and partly by chemical hormones, and may therefore be affected either by variations in the excitability of the nervous system or by the quality of the food. Excess of secretion is perhaps commoner in men, defect is more often found in women, but over-acidity is more prone to cause symptoms than under-acidity.

Motor Disorders.

Theseare of greater importance as a cause of dyspepsia than disorders of secretion. The stomach has two motor functions (peristalsis and "tone") and these may be dis ordered independently. Both are much under nervous influence, the vagus increasing tone and peristalsis, while the sympathetic has an opposite effect. Diminution of tone (hypo-motility, atony) is a commoner cause of symptoms than excess and is specially apt to occur in women. Emotional disturbances are prone to bring it about. Excess of tone and peristalsis are often asso ciated with over-acidity, whereas deficiency of tone and acidity often, though by no means always, coincide.

The symptoms of the functional disorders of the stomach differ notably from those of the more serious organic diseases. Pain, vomiting and wasting are absent, and the patient's chief complaints are of discomfort, flatulence, acidity, and so forth. As disorder of function is largely nervous in origin, treatment must be directed in great measure to the central nervous system, but acidity can be corrected by antacids, atony by strychnine, and so on. The diet of the patient must also be adapted to the weakened organ.

The Colon.

Theinvestigation of diseases of the colon has been facilitated by the introduction of the methods of exam ination by the X-rays after an opaque enema and by the sig moidoscope. Cancer is still the most serious affection, the sig moid and pelvic colon being its commonest sites. Treatment is by operation and, if undertaken early enough, is often successful. Ulceration of the colon is now divided into (a) dysenteric and (b) non-dysenteric. Dysenteric ulceration (see DYSENTERY) may be caused either by the amoeba histolytica or by dysenteric bacilli of the Shiga or Flexner type. The distinction between these different forms can be made by a bacteriological examination of the stools and by the serum agglutination test. Noh-dysen teric ulceration (ulcerative colitis) is not very uncommon as a primary disease in Great Britain. Its symptoms are the same as those of the dysenteric variety (diarrhoea with the passage of blood and mucus, some fever, pain and tenesmus) and it can be recognized by the use of the sigmoidoscope. Nothing is yet definitely known of its bacteriology. Antidysenteric serum is a powerful aid in the treatment of acute bacillary dysentery while emetine is a specific for the amoebic form. Non-dysenteric ulcer ation is treated by lavage and, in severe cases, by the operation of appendicostomy.

The frequent occurrence of little pouches (diverticula) in the wall of the colon has been established by modern methods of investigation. Sometimes these become inflamed when the con dition termed "diverticulitis" arises. It is not without danger. Much attention has been devoted in recent years to the alleged stagnation of the contents of the large bowel (colon stasis) with consequent absorption of poisons into the blood (auto-intoxica tion). Such stagnation is believed to be promoted by dropping or displacement of the colon or by the undue mobility of sec tions of it, and extensive operations have been undertaken for the correction of these conditions. While, however, auto-in toxication may sometimes take place, it is beginning to be realized that it is not nearly so frequent as was supposed and that opera tion for it is rarely necessary or advisable.

The Pancreas.

Thepancreas is still very largely the terra incognita of the abdomen, mainly on account of its inaccessible position. The introduction of tests for "pancreatic efficiency," however, has helped to make the diagnosis of its diseases easier. Amongst these tests are Loewe's adrenalin mydriasis reaction, the urinary diastase test, and the estimation of the unsplit fat in the stools. Glycosuria, also, is often an indication of the failure of the internal secretion (insulin).

New-growth (cancer) is the most serious disease of the pan creas and one of the commonest. It specially affects the head of the organ and usually shows its presence by the production of obstructive jaundice.

Acute pancreatitis (haemorrhagic necrosis of the pancreas) is one of the conditions which produce what is termed an "abdom inal catastrophe." It is difficult of diagnosis and is only curable by laparotomy.

Chronic pancreatitis, an interstitial inflammation or fibrosis of the organ, may result from partial obstruction of the duct, e.g., by gall-stones, or from an ascending infection of it. The symptoms are very much the same as those produced by cancer.

The

Liver.—Recent work has thrown a good deal of light on the nature of jaundice. It is now known that bile pigment is not produced in the liver cells but is derived from the breaking down of red blood corpuscles in the "reticulo-endothelial system"— a network of cells widely diffused in the body but especially in the spleen. The pigment so produced is picked out of the blood by the hepatic cells and transferred to the bile. Two chief varieties of jaundice are recognized: (a) obstructive, (b) non-obstructive. The former is due to any gross obstruction in the bile ducts such as may be caused by cancers or other tumours pressing upon or involving the ducts, impacted gall-stone and so forth. It is characterized by the complete absence of bile from the stools and its presence in the urine.

Non-obstructive jaundice, as it is usually called, is of two varieties—the haemolytic and the toxic. The former is due to increased destruction of red blood corpuscles and occurs to some extent in Addisonian (pernicious) anaemia and also in the rare disease known as "family jaundice"; toxic jaundice on the other hand is brought about by severe damage to the liver cells ren dering them incapable of transferring bile pigment from the blood to the bile. Many poisons act on the cells in this way, such as arsenic and phosphorus, as well as the toxins of certain organisms, e.g., those of yellow fever and some septic infections; poisons of "endogenous" origin may act similarly, as in acute yellow atrophy of the liver and the toxic jaundice of pregnancy. In all forms of non-obstructive jaundice bile is present in the stools but it may or may not be present in the urine. So-called "catarrhal jaundice," formerly believed to be obstructive, is now, largely as a result of the van den Bergh test, known to be due, in part at least, to direct damage of the liver cells, although obstruction of the ducts from catarrh also plays a part in its production. Much work has recently been done on the pathology of gall-stone formation. It is generally agreed that infection of the gall-bladder is a predisposing factor, the infection being usually conveyed through the blood stream in the same way as in cases of peptic ulcer. In addition it is possible that an excess of cholesterol in the blood contributes to their formation. For the other chief diseases of the liver, cancer and cirrhosis, see LIVER, DISEASES OF. (R. H.) BIBLIOGRAPHY.—C. D. Aaron, Diseases of the Digestive Organs Bibliography.—C. D. Aaron, Diseases of the Digestive Organs (Philadelphia, 4th ed. 1927) ; A. Bassler, Diseases of the Stomach and Upper Alimentary Tract (6th ed. 1926), and Diseases of the Intestines and Lower Alimentary Tract (192o) T. I. Bennett, The Stomach and UPper Alimentary Canal in Health and Disease (London, 1925) ; R. D. Carman, The Rontgen Diagnosis of Diseases of the Alimentary Canal (Philadelphia, 2nd ed. 192o).