SECTION VI.. Diseases of the Peritoneum and Abdominal Cavity.

DISEASES OF THE PERITONEUM AND ABDOMINAL CAVITY.

CHAPTER I. PERITONITIS.

Peritonitis, i.e., inflammation of the peritoneum, may attack any of the domesticated animals. It must, however, be regarded as an almost accidental and relatively infrequent disease. It is due to infection of very varying character, and from the clinical standpoint may assume one of two forms—acute peritonitis or chronic peritonitis.

ACUTE PERITONITIS.

The microorganisms which produce peritonitis have not been the subject of special investigation in the domesticated animals, though the colon bacillus and streptococci, so frequently found in the female genital tract after parturition, seem to be the most frequent causative agents. Certain putrefactive organisms may also bring about the disease.

The peritoneum may become infected, and acute peritonitis ensue under various circumstances.

All operations in which the peritoneal cavity is opened, such as castration of the cow and of the sow, laparotomy, gastrotomy, enterotomy, etc., may be followed by acute peritonitis if performed without sufficient regard to aseptic precautions. Peritonitis then usually assumes an acute septic form.

Even simple puncture of the rumen, though usually quite harmless if carefully performed, may by followed by local or general peritonitis should food material escape from the rumen and find its way into the peritoneal cavity.

One of the most frequent causes is infection from the genital tract soon after parturition. Here the agents of infection are not introduced directly into the cavity, but find their way there in consequence of a diseased condition of the mucous membrane and the uterine walls. Ascending infections of this character and infections by contiguity of tissue may only give rise to local peritonitis, though in too many instances they become generalised.

Acute peritonitis may follow infection from the stomach or bowel, should a foreign body perforate the rumen or reticulum and pass backwards towards the peritoneal cavity, or a serious intestinal inflammation (enteritis, invagination, etc.) facilitate the passage of microbes through the thickness of the intestinal wall.

Abscess of the liver, suppurative echinococcosis, renal infection, pyelo-nephritis, acute cystitis, rupture of the bladder, etc., may in a similar way become complicated with acute peritonitis.

Finally, abdominal wounds may cause interstitial ruptures and lesions in the serous membrane, accompanied by local exudation (kicks, horn-thrusts, blows from cart-poles, etc.), and if microbic agents are brought within the region of the lesion by the general circulation or otherwise, peritonitis may follow.

=Symptoms.= At first the symptoms are vague and imperfectly defined, and diagnosis is always very difficult during the first few days, except in cases where there exists a lesion or a condition previously recognised as likely to become complicated with peritonitis.

The early symptoms comprise fever, loss of appetite, arrest of rumination, rigors, constipation, etc., but these symptoms only attain full significance when accompanied by what has been termed “peritonism.”

The patient appears to be suffering from tympanites, as may really be the case, but the tympanites of the rumen and gaseous distension of the loops of bowel are not primary, and only result from the arrest of peristalsis. The primary condition is peritonism, i.e., distension of the peritoneal cavity, this being indicated by a symmetrical fulness of the right and left flanks.

The patients suffer from dull colic, and from this time always assume an attitude indicating pain. They remain in one position, with the back arched, the limbs gathered together, and the lower abdominal wall shortened. The face expresses suffering, the respiration is short and rapid and of the costal type, movement is painful and causes groaning, and the animals do not shrink when the lumbar region is pressed upon.

Palpation of the abdomen causes pain, and if practised at certain points may be followed by groaning. This method of examination, however, gives no further information, because the abdominal wall is rigid, tense, and as though tonically contracted.

Percussion is followed by tympanic resonance in the right and left upper zones, due to accumulation of gases of fermentation, and to distension of the peritoneal cavity itself. Towards the lower parts, however, percussion produces a dull sound. The presence of liquid can here be detected by the manner in which impulses are transmitted, particularly at the period of crisis and when much exudation exists.

Abdominal auscultation shows that the digestive movements are arrested. Peristaltic movement ceases, and the movements peculiar to the rumen and to the progress of food through the intestine are absent. Fermentation sounds, however, can be detected.

The heart beats are strong, rapid and violent, and yet the pulse remains feeble, though the artery is tense.

At a later stage, when the disease becomes aggravated, pain is less acute, depression is extreme, the animals no longer even drink, the abdominal wall becomes relaxed, and diarrhœa is succeeded by constipation. Palpation of the abdomen is less painful and does not cause groaning, but the pulse becomes feebler, much more frequent, imperceptible, and at last the animal dies from intoxication and exhaustion, caused by the fever and pain.

When peritonitis is due to rupture of the intestine or escape of alimentary material from the rumen into the peritoneal cavity, as may occur after puncture of the rumen or gastrotomy, etc., fever is not always very marked. The temperature may even fall below the normal point. Some cases vary greatly from the type described as regards their development, but the important features are always present, and the difference is chiefly found in the course of the disease.

=Diagnosis.= The diagnosis is rather difficult, but when there is colic, together with persistent peritonism, exaggerated sensitiveness to palpation and arrest of the functions of the digestive apparatus, there is little room for doubt.

=Prognosis.= The prognosis of acute peritonitis is very grave.

=Lesions.= The lesions vary with the primary cause (traumatism, metritis, suppurative echinococcosis, foreign bodies escaping from the digestive tract into the peritoneal cavity, etc.).

The parietal and visceral layers of the serous membrane are always inflamed, vascular, roughened, dull, and in places covered by vegetations. Between the loops of intestine and in the peritoneal pockets there are discovered more or less numerous and more or less thickened false membranes, presenting the characteristics of the false membranes seen in acute pleurisy.

The liquid varies in quantity and in colour, being sometimes lemon-yellow, sometimes purulent, sanguinolent, or even blackish, and of putrid odour.

The lesions may appear more marked at a particular point, such as the uterus, rumen, hypochondrium, etc., and the intestinal loops may become partly fixed in position by false membranes. In time these false membranes may solidify and undergo transformation into fibrous tissue.

=Treatment.= Treatment is generally useless in cases where peritonitis results from rupture of the bladder or intestine or from eventration. Complete and perfect cleansing of the infected abdominal cavity is impossible in large animals.

In other cases the animals should be left completely at rest, and purgatives should be avoided. Movement or the administration of purgatives provokes peristalsis, and, as a consequence, almost inevitably leads to generalisation of a lesion which might otherwise have some chance of remaining localised, as in pelvi-peritonitis and peritonitis due to foreign bodies issuing from the rumen or reticulum. If the movements of the intestinal loops disperse the septic liquids beyond the points originally injured, the whole cavity becomes inoculated and generalised peritonitis is set up.

Emollient and diuretic drinks containing opium, and oatmeal or linseed gruels, have the advantage of soothing the colic and preventing stagnation in the bowel. These should be given from the first and solid food entirely avoided.

The sides of the abdomen should be mildly stimulated, provided the operation does not give rise to undue pain and cause the animals to struggle. Vesicants are preferable to mustard, though mixtures of mustard and linseed meal may be used, and, if found advantageous, can be repeated.

Mercurial salts, though much used in earlier times, are now entirely given up. Diuretics, such as bicarbonate of potash, nitrate of potash, alcohol, and acetate of ammonia, should be used, according to circumstances.

Aseptic washing out of the peritoneal cavity would be advantageous, but in large animals cannot easily be effected.

CHRONIC PERITONITIS.

=Causation.= Chronic peritonitis may occur as a termination of the acute form, but it may also develop gradually as a result of disease of the kidney (pyelo-nephritis), of the uterus or ovaries (chronic metritis, tumour of the ovary), of the liver (suppurative echinococcosis), or of any other lesion in neighbouring parts which is capable of setting up continued irritation.

It also accompanies tuberculosis of the peritoneum, cancer of the peritoneum, chronic disease of the bladder, etc. Further, it appears, but more rarely, in certain chronic diseases, such as chronic dysentery and lymphadenitis.

=Lesions.= The lesions consist of local thickenings of the peritoneal layers, and numerous papilliform vegetations scattered very irregularly over the parietal peritoneum, mesentery, epiploon, etc.

If the disease has existed for a long time, fibrous bands or solid adhesions may be discovered, connecting various parts of the digestive apparatus with one another, or with the abdominal walls.

Sometimes the intestinal contents seem almost entirely adherent to the abdominal walls.

The primary lesions of the liver, spleen, kidneys, or genital organs, from which the disease originated, are also found.

The quantity of exuded liquid varies greatly; sometimes there is a great quantity of a transparent or lemon-coloured liquid, resembling that of ascites. In other cases the liquid is scanty, and may be confined between layers of bowel, which are connected by an inflamed layer of epiploon.

These old-standing lesions cause atrophy of the abdominal organs, contraction of the intestine, and sometimes true obstruction.

In chronic tuberculous peritonitis the adhesions between the intestine and the abdominal walls may be enormous. The peritoneum is generally covered with great masses of tuberculous new growth, while the mesenteric and sublumbar lymphatic glands are attacked.

=Symptoms.= The disease develops without marked fever or grave interference with the chief functions, and the first approach of the disease may, therefore, easily be overlooked. Chronic peritonitis, moreover, may remain strictly localised.

When the disease assumes the ascitic form the dominant sign is readily detected. Where new membranes form the principal lesions the symptoms are much less definite, and the existence of disease is chiefly indicated by digestive disturbance, such as diminished peristalsis, the occurrence of colic, diarrhœa, etc.

It is well to remember, however, that these troubles often follow an ascitic stage, which may gradually disappear owing to the fluid becoming absorbed. Even in the fibrous form, where the intestines appear completely glued together by adhesions, the volume of the abdomen is increased and the belly is deformed, as in ascites.

In time patients suffering from primary lesions of an important internal organ are affected in their digestion, lose flesh and become anæmic, and finally cachectic.

=Diagnosis.= The diagnosis is by no means easy, particularly in the fibrous forms, owing to the great difficulty of discovering the primary lesion.

=Prognosis.= The prognosis is grave, though it must not be regarded as necessarily fatal. In cases resulting from genital diseases, and in localised chronic peritonitis resulting from persistent, but not excessive, mechanical violence, complete and perfect recovery may occur.

On the other hand, in cases of chronic lesions of the liver, kidneys, heart, etc., and in tuberculosis, carcinoma, etc., recovery cannot be expected.

=Treatment.= Treatment should be directed towards combatting the chronic inflammation. With this object resort may be had, when necessary, to persistent stimulation of the sides of the abdomen, mild blisters and mustard plasters, or friction with turpentine.

The food should be easy of digestion, and of first-rate quality. The most useful drugs comprise mild, unirritating diuretics, general stimulants, and tonics.

Animals affected with incurable lesions should not be treated.

ASCITES.

True ascites consists in dropsy of the peritoneum, unaccompanied by inflammation of that membrane, or by the presence of infectious microorganisms in the transuded liquid. Properly speaking, it is not a morbid entity, but only a symptom common to several very complex diseases.

=Causation.= The diseases which produce it may be set forth under five principal heads:—

(1.) Cardiac affections in general, particularly chronic lesions of the heart, interfering with venous circulation, and causing prolonged stasis of blood in an organ or tissue.

(2.) Pericarditis due to foreign bodies, and the various forms of pseudo-pericarditis, i.e., lesions in the neighbourhood of the heart, causing compression of that organ and of its vessels.

(3.) Generally speaking, all lesions which interfere with the return circulation, particularly lesions of the liver (distomatosis, echinococcosis, and interstitial hepatitis). These produce compression of the portal vein or other obstacle to circulation, and the transudation is exclusively localised in the abdominal cavity. The connective tissue does not become infiltrated.

(4.) Diseases of the kidneys (nephritis, pyelo-nephritis), which secondarily produce cardiac disturbance.

(5.) Gestation, which causes compression of certain digestive viscera, and of certain veins of the pelvic cavity.

Ascites was formerly regarded as always forming a complication either of anæmia or of hydræmia. We now know that the primary cause of these three collections of symptoms (ascites, anæmia, and hydræmia) is the development of certain chronic wasting diseases or chronic lesions of the heart, liver, and kidney, which act and react upon each other.

=Symptoms.= True ascites is unaccompanied by fever. The condition develops slowly, insidiously, and therefore escapes notice at first. Only when the exuded liquid is present in considerable quantities is the condition apparent. The symptoms are similar to those of ascites following chronic peritonitis.

The transuded liquid progressively accumulates in the peritoneal cavity, the lower portion of which it distends. When the animal is viewed from behind the enlargement appears symmetrical, despite the position of the rumen. The intestinal contents float on the liquid and are thrust upwards towards the lumbar region. On palpation, the abdominal cavity seems unusually full, the tension differing in proportion to the quantity of liquid. The accumulation of liquid may become considerable and interfere with respiration, circulation, and movement. Very marked anæmia always exists, the mucous membranes are extremely pale, the respiration is rapid, the pulse feeble, all these symptoms being consequent on the primary disease of the heart or liver. Percussion of the lower part of the belly produces a dull sound. On the left side this dulness often extends from the linea alba as high as a horizontal line, uniting the external angle of the ilium and the hypochondriac circle. On the right it is bounded by a horizontal line. Percussion or, better still, palpation provokes on one side of the abdomen a wave or impulse of the liquid, perceptible to the touch or even to the view at the opposite side.

=Diagnosis.= In general diagnosis is easy, thanks to the slowness with which the disease develops.

=Prognosis.= The prognosis varies in each case, more especially according to the more or less marked debility of the animal. Ascites due to gestation is usually of a very simple character, but if it is the result of pericarditis produced by a foreign body, or of nephritis, the outlook is very gloomy; lesions of the kidney in particular showing little tendency to recovery. Finally, the prognosis varies when the ascites follows disease of the liver, for certain exceptional cases have been noted in which an attack of hepatitis has led to the disappearance of the transudate.

=Lesions.= The lesions peculiar to this disease are very trifling. Transudation takes place without inflammation of the peritoneum, although the veins of the abdominal cavity are abnormally dilated. The abdominal wall is thin and distended, and the tissues are colourless as though soaked in water. The cavity is distended with a clear lemon-coloured albuminous liquid free from blood corpuscles.

=Treatment.= The treatment must vary according to circumstances, i.e., having regard to the primary cause. Ascites due to gestation, which is always slight, calls only for simple hygienic treatment; but when the disease is attributable to lesions of the heart, pericarditis, or chronic affections of the kidney or liver, it is generally incurable in common with the original lesions themselves.

If, finally, no clearly defined cause can be detected, or if the ascites is due to chronic peritonitis, treatment should be attempted. The first step may consist in evacuation of the liquid for the purpose of reducing the excessive pressure on the diaphragm and facilitating respiration. For this purpose an aseptic puncture is made with a fine trocar on the right side of the abdomen in the flank region, about equidistant from the umbilicus and the loose flap of skin in front of the stifle. The absorption of liquid may afterwards be assisted by administering diuretics, such as digitalis, bicarbonate of potash or nitrate of potash, and by giving lukewarm drinks, tonics, etc. In Germany injections of pilocarpine have been suggested, but it is doubtful whether they have proved satisfactory.

PERITONEAL CYSTICERCOSIS.

The above name has been given to a parasitic disease caused by the infestation of young animals, such as calves, lambs and young pigs, with embryos of the Tænia marginata of the dog.

=Symptoms.= Peritoneal cysticercosis is often of so mild a character, and the number of embryos which penetrate the body so small, that in the majority of cases there are no visible symptoms. It is not until the meat comes to be dressed by the butcher that little cysts (Cysticercus tenuicollis) are discovered in the abdominal cavity.

Unfortunately, in exceptional cases it may also happen that the number of embryos in the abdominal cavity is so great as to produce lesions of acute hepatitis, acute peritonitis, and sometimes pleurisy. These grave forms are more common in young pigs and lambs.

The animals appear dull, feeble, exhausted and without appetite, but exhibit marked thirst, lose flesh and become anæmic in a few days. Soon afterwards they show symptoms of acute peritonitis, with exudation of fluid, and death may follow in a week or two.

In cases where infestation is less marked, the animals may exhibit only progressive anæmia, without well-developed symptoms of peritonitis, until death occurs.

=Lesions.= On post-mortem examination a sero-sanguinolent exudation is seen, together with more or less numerous false membranes, and a varying number of young cysticerci floating freely in the liquid or enclosed in the folds of the mesentery. The cystic vesicles are spherical, ovoid, or elongated, and translucid or opalescent. They are some millimètres in diameter, and in some cases are very numerous, ranging from a few hundreds up to several thousands, but in others comparatively few.

The liver shows signs of intense hepatitis, caused by embryos burrowing into its tissue.

=Causation.= The causes are limited to a single fact, viz., ingestion of the eggs of Tænia marginata, which are spread over the fields in the excrement of dogs suffering from that parasite.

=Diagnosis.= The diagnosis can only be arrived at by a post-mortem examination, when cysticerci in various stages of development are discovered.

=Prognosis.= The prognosis is difficult to indicate, because everything depends on the intensity of the infestation.

=Treatment.= No curative treatment is possible, direct action on the developing parasites being impracticable. Nevertheless, some patients survive, and after having shown grave general disturbance may gradually improve.

The only efficacious treatment is of a prophylactic nature, as in cœnurosis and echinococcosis. Dogs suffering from tæniæ should periodically be treated and freed from their parasites.