SECTION II.. Diseases of the Digestive Apparatus.

DISEASES OF THE DIGESTIVE APPARATUS.

SEMIOLOGY OF THE DIGESTIVE APPARATUS.

The group of diseases which affect the digestive apparatus is one of the most important in bovine pathology, because almost all animals of the bovine species are bred with the object of utilising to the full their powers of digestion and assimilation.

Whether we consider adult fat animals, calves intended for slaughter or milch cows, the object sought is always the same—i.e., to secure the greatest possible economic return through the medium of the digestive functions.

Even although in working oxen there is no tendency to overfeeding, the animals remain none the less predisposed to diseases of the digestive apparatus; the meal times are often too short, and rumination has to be performed under the yoke or during work—in a word, under unfavourable physiological conditions.

=Semiology.= To ensure correct diagnosis it is necessary here, perhaps more than in any other department of pathology, to be capable of grasping the symptoms or syndromes and signs afforded by the different parts of the digestive apparatus; to know how to co-ordinate and group them so as logically to deduce the final synthesis, the diagnosis. The diagnosis proving correct, the prognosis becomes easy, and this is the chief object from the economic standpoint. The practitioner who undertakes treatment knows how to deal with the case, and the owner likewise knows what he undertakes to do.

Although this classification may appear arbitrary, we shall consider successively diseases of the mouth, of the pharynx, œsophagus, stomach, intestines, etc., firstly describing the symptoms characterising these diseases. At the same time we should state that many symptoms are common to a large number of diseases and in themselves have absolutely nothing characteristic. They are simply sign-posts capable of showing the way.

=Mouth.= External examination reveals the condition of the muzzle, the lips and their commissures, and the surroundings of the buccal opening, and detects the existence of any desquamation, rents, eruptions, ulcerations, etc., which may be present.

In quiet animals the practitioner can examine the cavity of the mouth single-handed, but in troublesome animals it becomes necessary to have an assistant, who seizes the muzzle with one hand and the tongue with the other, or who simply fixes the animal’s head. In exceptional cases it will be necessary to secure the patient to a post, tree, or wall. The mere attempt at examination will show whether there is trismus or absolute freedom of movement in the jaws.

By introducing the fingers between the commissures and applying them to the bars or to the free portion of the tongue, the practitioner will be able approximately to estimate the local and general temperature. The sensations experienced will also inform him of the degree of moisture or dryness of the mouth and of its sensibility.

On separating the jaws, he will note the odour exhaled and its possible abnormalities—its acid, sourish, fœtid, or putrid character. He will directly observe any anæmia or hyperæmia of the mucous membrane, from the inner surface of the lips and cheeks up to the soft palate, although owing to the thickness of the buccal epithelium it is not always easy to estimate anæmia or hyperæmia in the ox. The surface of the tongue should also be examined, and a note made whether it appear dry, pasty, dusty, sooty, etc., though these appearances are occasionally apt to lead one astray. The observer should also inquire regarding want of appetite, depraved or exaggerated appetite, etc.

Even the manner in which the animal picks up its food will serve to direct his attention to the development, or possible existence, of some disease of the mouth, although want of appetite is not always characteristic of a lesion in the pharynx or œsophagus, but sometimes of a lesion in its neighbourhood, like hypertrophy of the retro-pharyngeal or bronchial lymphatic glands.

This examination will also detect the existence on the lips of wounds, cuts, injuries or specific eruptions (aphtha, tuberculous ulcerations, the ulcerations of gangrenous coryza, etc.) on the gums indications of gingivitis, periostitis, mercurial poisoning, actinomycosis of the maxilla, and ulcerations of all kinds; on the tongue, of wounds, of simple or specific inflammatory eruptions (aphtha, the ulcerations of actinomycosis, tuberculosis, gangrenous coryza, etc.), as well as the swellings due to superficial or deep-seated glossitis. By the same method of examination, though with somewhat more difficulty, one can detect abnormal mobility, irregularity of development, caries, etc., of the teeth, the condition of the excretory ducts of the salivary glands, the state of the hard and soft palate, and the existence of fissures, vegetations, polypi and tumours.

=Salivary glands.= The salivary glands, particularly the parotid and submaxillary, should be examined by direct inspection and palpation.

Direct inspection reveals the existence of swellings, deformity of parts, increase in salivation, or ptyalism, which sometimes occur in conjunction with foot-and-mouth disease, actinomycosis, acute stomatitis and mercurial poisoning, as well as increase in size of the salivary ducts.

Palpation reveals the degree of sensibility of the parts, the existence of œdema, induration, cysts, and, more frequently, distension of the salivary ducts as well as the presence of calculi, tumours, the direction of fistulæ, etc.

Difficulties may occur, particularly when the submaxillary and parotid glands are affected; but methodical and complete examination will usually enable one to differentiate the conditions.

=Pharynx.= The pharynx may be examined externally by inspection and palpation, and internally by direct digital palpation. Inspection reveals possible deformities of the region of the gullet, palpation the condition of the tissues as well as abnormal sensibility and infiltration. Internally, digital examination must be cautiously conducted, and after a strong gag has been securely inserted in the mouth. Under such conditions it is without danger. The hand being inserted exactly in the median line will detect obstructions which may already have been partly identified by external palpation, as well as the existence of inflammation with or without the formation of false membranes, and of ulcerations, polypi, etc.

=Œsophagus.= In consequence of its anatomical formation, situation and course, the œsophagus may be divided into two distinct parts—viz., the cervical, which can be examined from the outside, and the thoracic, which cannot so be examined.

The cervical part may be examined by inspection, by palpation from one side, or by palpation with both hands and from both sides.

Inspection leads to the detection of changes in the shape of the œsophagus and of the jugular furrow. In fat subjects, however, it is of little value. As the position and the course of the œsophagus are known, unilateral palpation, or, better still, bilateral palpation, employing both hands, is of very much greater service. These methods reveal the presence of swellings, infiltrations, changes in shape and sensibility, the presence of foreign bodies, the existence of dilatations or contractions of the tube, etc.

Auscultation and percussion, though recommended by some practitioners, are not of much service.

Inability to swallow, due to change in the œsophagus, is also detected by inspection. Its existence suggests a number of possible conditions, such as fissure or ulceration of the œsophagus, compression in the mediastinal region as a result of tuberculous or other disease, contraction or dilatation of the œsophagus, etc. Furthermore, inspection will betray the existence of dilatation of the tube, to which vomiting and regurgitation of food are sometimes due.

Internal exploration is the only method of detecting changes in the thoracic portion, and may also be utilised to locate lesions in the cervical region. It is practised by passing a sound of small calibre or any flexible cylindrical object, such as a cart rope, etc. The patient must be fixed with the head extended on the neck and a proper gag or speculum introduced into the mouth. Exploration assists us in recognising the existence of inflammation of the œsophagus, true or false contraction, dilatation and the presence of obstructions.

In animals of the bovine species all these lesions—viz., inflammation of the œsophagus, fissuring and ulceration, obstructions, compressions, dilatations and contractions of the tube—although not very frequent, are nevertheless from time to time encountered.

=Stomach.= Exploration of the stomach or of the different gastric compartments presupposes an exact knowledge of the respective positions of the different reservoirs. Topographical anatomy shows that the rumen is situated in the left flank, and that it occupies the whole of the left abdominal region from the diaphragm to the pelvic cavity. As a consequence, it may be explored from the region of the twelfth rib; it is inclined slightly from above downwards, and from left to right, its extreme right border extending as far as, or a little beyond, the white line.

The reticulum, the smallest of the four reservoirs, is situated in the sub-ensiform region at right angles to the median plane of the body. On the left it touches the rumen and the diaphragm; on the right side it is in contact in front with the diaphragm, above with the omasum, and to the right and towards the rear with the abomasum. The omasum is situated above the reticulum and conical right portion of the rumen; in front it touches the liver, and towards the back and left the rumen. The abomasum is situated obliquely in the right hypochondriac region, its anterior surface resting on the lower wall of the abdomen towards the middle and right side of the body, its pyloric portion extending upwards, behind the right hypochondriac region.

=Rumen.= The rumen can be examined by inspection, palpation, percussion, and auscultation. The use of the œsophageal sound and of the trocar and canula is also of value in diagnosis.

Inspection affords information of a varying character, according to the moment when it is practised, even in a condition of health. It only extends to the condition of the flank before or after a meal, etc., emptiness of the rumen being accompanied by hollowness of the flank, and distension, following an abundant meal, by fulness in this region.

When digestion is not proceeding normally, the flank may be distended unduly by gaseous accumulations or by the presence of solid food. In abdominal and mediastinal tuberculosis and in gastro-enteritis there may be simple tension or slight dilatation. When indigestion or enteritis is entering on a favourable stage, the flank may appear hollow, and in cases of chronic diarrhœa it may appear retracted.

Digital examination or palpation may be practised over the entire region of the flank. It shows whether the rumen is full or empty, reveals the consistence of the contained food in cases of chronic indigestion, the sensibility of the walls, and the rate and order of the muscular contractions. Direct or indirect percussion may be carried out on a horizontal line from the twelfth rib as far back as the flank, and vertically from the lumbar vertebræ to the white line. In health one discovers in young animals an upper zone of normal resonance due to gas, a zone of semi-dulness and an inferior zone of absolute dulness, due to the liquids in the rumen. The spleen, which is attached to the supero-anterior surface of the left side of the rumen, does not seriously restrict the area open to percussion.

In pathological conditions percussion from above downwards may produce a tympanitic sound, due to gaseous indigestion or a clear sound throughout the greater portion of the vertical diameter suggestive of acute gastro-enteritis with the formation of gas in the rumen, or of adhesive peritonitis preventing the rumen from collapsing. Indigestion due to excess of solid food, on the contrary, is characterised by a dull sound throughout the entire region from above downwards. Percussion along a horizontal line permits of the delimitation of certain zones which vary a great deal in area, according to the case.

Auscultation is more instructive than percussion. Like percussion, it may be practised throughout the entire depth of the abdomen, from the transverse processes of the lumbar vertebræ as far as the white line, and in a horizontal direction from the eleventh rib to the region of the flank.

Auscultation of the upper zone enables one to detect sounds of deglutition, gurgling sounds (glou-glou), and a sound resembling falling water, due to the movement of solids or liquids in the rumen and reticulum. The sounds heard vary in different cases, and depend on the state of repletion or of emptiness of the rumen.

Auscultation of the middle zone reveals:

Firstly, a very special crepitation sound, which may be compared to the deflagration of a handful of salt thrown on burning coal. It is believed to result from the bursting of bubbles in the contents of the rumen under the action of normal digestion.

Secondly, a churning sound produced by the rhythmic peristaltic contractions of the rumen, by which the substances ingested are very intimately mixed. By applying the ear over the flank region or by palpation the rhythmic contractions of the rumen, two per minute in most cases, can readily be perceived.

In practice examination of the rumen is confined to these four methods.

=Puncture.= From an exclusively scientific point of view, exploration of the rumen also comprises analysis of the gas collected through puncture and analysis of the liquids removed by aspiration (first stages of gastric digestion). Normally, these gases, in the order of their abundance in the mixture, consist of the following: Carbonic acid, carburetted hydrogen and nitrogen.

In disease, and in most cases of abnormal fermentation, the carburetted hydrogen is greatly in excess of the carbonic acid. In chronic gastro-enteritis, ammonium sulphide and other offensive gases are found in addition.

=Chemical analysis.= In the rumen the ingested food is macerated in an alkaline liquid at a temperature of 100° to 101° Fahr. (the alkalinity is due to the saliva). This process markedly modifies the composition of the ingested matter. Nevertheless, the upper portion in contact with the gas sometimes presents a slightly acid reaction, probably due to carbonic acid. The sugary and fatty materials contained in the food respectively undergo lactic and butyric fermentation. Only a small quantity of the starch, however, is transferred into sugar. In the calf, and in very young animals, the reaction of the rumen is acid throughout the entire period of sucking. In disease, when rumination has long been suspended and chronic loss of appetite or gastro-enteritis exists, the reaction is generally acid. The sugars, gums, and soluble salts of forage, roots, etc., are dissolved in the rumen, but fatty materials undergo no modification.

The reticulum, which is the smallest of the gastric compartments, is situated in the sub-ensiform and retrodiaphragmatic regions, extending right and left of the middle line to a nearly equal distance. Above and to the left it communicates freely with the rumen, to the right with the omasum.

In practice it can only be examined in two ways: inspection and palpation.

By inspection changes in the configuration of the ensiform region may sometimes be detected. Such changes are rare, and must be distinguished from congenital deformity. They sometimes accompany inflammation of the reticulum produced by a foreign body, when the lower abdominal wall is directly perforated by such body.

In cases of inflammation of the reticulum due to foreign bodies, abscess formation, perforation, etc., it is possible to detect œdematous infiltration, abnormal sensibility, fluctuation and increased heat, etc., by manipulating the parts with the fingers or the clenched fist.

If the evidence pointing to the presence of a foreign body in the reticulum is considered sufficient, gastrotomy may be performed and the interior of the viscus examined with the hand, but although the operation is possible it is very rarely practised.

=Omasum.= The omasum occupies, so to speak, a position inverse to that of the reticulum, lying deep down on the right side, behind the diaphragm, under the hypochondrium, and above the abomasum and reticulum.

It is the only gastric compartment which cannot be examined, although when impacted it may be felt on the right side.

=Abomasum.= The abomasum is lodged in the lower part of the right flank under the circle of the hypochondrium. It extends obliquely from below, upwards from the sub-ensiform to the sublumbar region. The smaller curvature is turned towards the rumen on the left side; the larger curvature is in contact with the abdominal wall. In spite of what has so often been stated by those who have never seen it, the abomasum can be examined and is accessible along the circle of the hypochondrium.

In adults useful information can rarely be obtained by inspection; but in sucking calves the abomasum, if distended by indigestion, gastro-enteritis, etc., sometimes appears prominently in the right abdominal region. Palpation with the fingers or with the fist will detect exaggerated sensibility, irritation, inflammation, or distension.

Percussion and auscultation furnish no very precise information. The information obtained by the above-described examination of the stomach is in practice amplified by a search for certain symptoms which are usually easy to detect. They comprise:

(a) Suppression or irregularity of rumination. This very important symptom suggests the degree of gravity of the digestive disturbance, and to some extent the gravity of the general condition. Suppressed rumination is a common symptom in many diseases, some of which are purely digestive, though all are not. It is, however, a grave sign in most cases.

(b) Eructation, which is usually frequent, may be regarded as normal provided the exhaled gas preserves the fresh odour of grass or of the food swallowed, like brewers’ grains, turnips, etc. Sometimes the gas is sour, acid, fœtid, or putrid, all of which conditions indicate disease.

(c) Yawning is not common. It becomes frequent and attracts attention in certain abnormal conditions; in others, again, it may be completely suppressed.

(d) Nausea and vomiting are rare. Vomiting is commoner in calves, and results from inability to digest the milk, or simply to over-distension of the abomasum. The matter vomited by adults usually consists of partly masticated food, and is derived from the rumen; while the contents of the abomasum are occasionally rejected, in which case the material is of pulpy consistence and has an acid smell.

(e) Digestive disturbance is sometimes accompanied by various modifications in the breathing, such as immobilisation of the hypochondriac region and of the diaphragm; abnormal sensibility and reflex coughing on palpation, and, in inflammation of the reticulum due to foreign bodies, costal respiration.

It is by methodically observing, grouping, and classifying the symptoms presented that one is enabled to detect the links connecting them.

=Intestine.= The intestinal mass is contained in the right half of the abdomen above the compartment of the stomach. The large intestine occupies the upper zone, corresponding externally with the hollow of the flank from the thirteenth rib to the haunch. The small intestine occupies the middle zone from the thirteenth rib to the entrance to the pelvis and the stifle region; the inferior zone is occupied by the rumen and abomasum, and in pregnant females by the gravid uterus.

Notwithstanding these indications it is somewhat difficult to examine the mass of the large intestine, separated as it is from the abdominal wall by the =U=-shaped inflection of the duodenal loop, of which the deep retrograde branch is in contact with the terminal portion of the floating colon.

Inspection of the right flank furnishes no information of value in diseases of the intestine, nor is auscultation of much service beyond enabling one to detect the frequency, diminution, or absence of borborygmus. Palpation alone is really of service. Practised gently and superficially with the tips of the fingers it detects abnormal sensibility in acute cases of enteritis; when with more energy, palpation reveals whether the bowel be full or empty, provided that the muscular resistance be not too marked.

=Colic.= In colic the clinical signs, their varieties, and the lesions which give rise to them are of much more importance. When it results from intestinal congestion à frigore (due, for example, to the ingestion of cold water), colic is usually violent, sudden, and of relatively short duration. In other cases it is violent and prolonged for several hours, a whole day, or even two days, and may be followed by coma and suppressed peristalsis; it then indicates invagination, volvulus, or strangulation. Sometimes, on the contrary, it remains dull and is slow and continued (acute gastro-enteritis, hæmorrhagic gastro-enteritis, etc.).

Finally, colic of the latter character may, in addition, be accompanied by icterus, in cases of retention of bile, biliary calculi, hepatitis, etc.

=Anus.= Examination of the anus is easy. Simple inspection reveals its presence or absence, and consequently the existence of congenital rectal atresia, which is somewhat common in calves and colts. Digital exploration is, however, sometimes useful, for in occasional cases an anus may exist, which externally appears normal, but terminates in a sac, the rectum being closed by a membranous partition.

Nothing is easier to recognise than tenesmus; it occurs in cases of profuse diarrhœa, diarrhœa of calves, and dysentery in newly-born animals.

=Rectal exploration.= Exploration of the rectum is a last and most valuable means of confirming the diagnosis in all visceral diseases of the pelvis and abdomen. To utilise this method to the full, the rectal pouch should first be thoroughly emptied by the free use of enemata, the subsequent examination being made with great care. The animal’s hind legs being secured, the operator smears his hand and forearm with some fatty substance, and, forming the fingers into a cone, introduces them with gentle pressure through the anus, the palm of the hand being turned downwards. Passing the hand gently along the rectum, the operator will be able to distinguish the conical posterior pouches of the rumen, the loop of the duodenum, the mass of convolutions of the small intestines and of the colon, etc. Next, he will examine the vagina, uterus, bladder, ureters, kidneys, aorta, and the pelvic and sublumbar lymphatic glands. He may be able to recognise distension of the rumen with food, twists of the intestine, herniæ, mesenteric or diaphragmatic invagination or volvulus of the bowel, etc.

In other cases he may be able to discover lesions of the kidney, of the uterus, of the broad uterine ligaments, of the ovaries, or of vessels.

In all cases it is desirable to make a methodical and complete examination, whatever the primary object may have been. Such an examination may be carried out as follows: The operator having introduced his hand into the rectum, begins by examining the state of the pelvic organs, the rectum, base of the vagina, the body and horns of the uterus, the bladder and the lymphatic glands and ligaments of the pelvis.

By laying the hand flat in the rectum and pressing gently downwards the anterior border of the pubis may be felt, somewhat more deeply placed. The rectum is then thrust slightly to the right, and the ascending branch of the right ilium, as high as the sacro-iliac articulation, and the lower surface of the sacrum, are directly examined; lastly, the hand is directed towards the left, gliding down the left ilium, and returning to the point of departure. In this way the state of the pelvic floor, of the arteries, veins, and lymphatic glands, etc., the degree of mobility, tension, or fulness of the uterus, as well as the condition of the broad ligaments, are all ascertained.

Still more deeply placed, and at the extreme limit to which the arm can be introduced, will be found some or all of the above-mentioned organs—viz., the small intestine, large intestine, kidney, etc.

=Defæcation: Examination of the fæcal material.= The character of the fæces is very important in certain diseases; e.g., diarrhœa assumes a varying importance, according as the discharges are of an alimentary, serous, mucous, or sanguinolent type, and are slight, temporary, intense, profuse, or continued. In other cases defæcation is slow, becomes difficult, and various degrees of constipation exist. Defæcation may be completely suppressed, as in invagination or strangulation of the intestines; on the other hand, one may observe diarrhœa, dysentery (microbic or sporozoic diarrhœa), and intestinal hæmorrhage. The last named may be of varying degrees of acuteness, from the passage of simple drops or streaks of blood, distributed over almost normal excreta, to the passage of unchanged blood in liquid jets or in clots.

=Macroscopic examination.= Macroscopic examination takes cognisance, firstly, of the quantity (40 to 80 lbs.), consistence (firmness or softness), colour (olive green, blackish green, greyish black, sooty, or tarry) and odour (normal, fœtid, putrid, etc.) of the fæces.

Sometimes the excreta are moulded and covered with glairy mucus, or contain such abnormal products as undigested food (a sign of chronic diarrhœa), false membranes, false membranes due to pseudo-membranous enteritis, fibrinous clots, or parasites like liver flukes, tæniæ and strongyles.

=Microscopic examination.= Microscopic and bacteriological examination is sometimes useful; and even when macroscopic examination has revealed nothing, it is possible to detect the presence of the eggs of parasites like flukes, strongyles, hooked worms, etc., the presence of sporozoa (as in intestinal coccidiosis) and of specific microbes, as in the diarrhœa of calves, etc.

It is only by the synthesis of methodically collected signs that one finally succeeds in exactly diagnosing the numerous diseases which may affect the intestine: intestinal congestion, invagination, volvulus, intestinal strangulation (mesenteric or diaphragmatic herniæ, etc.), atresia of the anus, acute or hæmorrhagic enteritis, or intestinal helminthiasis.

=Liver.= The liver is situated in the right sublumbar region. It is fixed behind the diaphragm and under the hypochondriac region, and extends from the ninth to the thirteenth rib. It can be examined by palpation through the last intercostal spaces and behind the thirteenth rib. In health it is difficult to pass the fingers sufficiently under the hypochondriac circle to reach the liver; but in case of morbid hypertrophy it extends more or less beyond the last rib, and palpation between the last ribs sometimes reveals abnormal sensibility.

Percussion better than palpation enables one to delimit the space occupied by the liver, particularly towards the back, where there is no interposed layer of lung. Percussion is especially useful in detecting hypertrophy due to cancer, tuberculosis, echinococcosis of the liver, etc., or hepatic atrophy. In isolated cases icterus may exist, confirming the conclusions otherwise arrived at.

=Pancreas.= The pancreas is situated rather deeply in the right sublumbar region, below the kidney, behind the liver, above the floating colon, and within the duodenal loop. It is therefore very difficult to examine; moreover, the diseases which affect it are still little understood.

The point most prominently brought forward by this demonstration of the topographical anatomy and semiology of the digestive apparatus is the difficulty of accurately diagnosing digestive diseases in the ox when one confines oneself to a superficial examination. To have any chance of arriving at an exact diagnosis, methodical and thorough examination is indispensable. Given this condition, accurate diagnosis becomes possible, despite all difficulties.