ASCITES IN CARNIVORA.
Causes: obstructed flow of blood in hepatic, portal or renal veins, or in vena cava, renal, heart, liver or splenic diseases, pulmonary congestion, asthma, tuberculosis. Symptoms: pot-belly, hollow above, drooping back and loins, flat percussion sound and fluctuation, change of position changes area of flatness, anæmia, debility, scanty urine, diarrhœa, no fever. Diagnosis: absence of fever, general fluctuation changing its seat by turning the patient, not confined to a given organ like the bladder or womb. Lesions: quantity and composition of liquid, lesions of primary diseases. Treatment: Correct if possible the primary disease, evacuate the liquid, compress on abdomen, iodine solution for irrigation, saline purgatives, diuretics, pilocarpine, bitters, iron, sunshine.
Causes. Ascites is generally the result of some obstruction to the return of blood from some abdominal organ, but may also come from renal disease, or hydroæmia in which general dropsy is likely to occur. The dog is specially subject to heart disease, and disease of the right heart (tricuspid insufficiency, dilatation, hydro-pericarditis, fatty degeneration, etc.) throws the blood back on the whole venous system and the extensive and dilatable portal veins are especially liable to suffer. Diseases of the liver, so common in pampered house dogs, still more directly block the portal circulation and induce ascites. Tumors in the liver or spleen or in the lymph glands of the porta act in this way, also cirrhosis, tuberculosis, cancer, hepatic congestion, and degeneration. Constrictions of the vena portæ by false membranes the result of former peritonitis must also be recognized. As more distant causes, must be named obstruction to the pulmonary circulation, as in congestion, asthma, tuberculosis and diseases of the left heart. Seventy-eight cases were traced as follows: to diseases of the heart and pericardium, 10; to tuberculosis, 8; to pleurisy, 4; to malignant tumors of the liver and lung, 2; to hepatic disease without heart lesion, 3; to cancer of the liver, 1; (Cadiot).
Symptoms. Enlargement of the belly is marked and peculiar, the liquid accumulating below, pushing outward the lower ends of the ribs, and making the lower part of the abdomen baggy while the upper part, under the lumbar transverse processes, is flattened or hollow. The back and loins droop forming a concavity superiorly, so that the belly may almost drag on the ground. On palpation this pendent abdominal sac gives the sensation of a mobile fluid without the usual firm outlines of the intestinal masses, and when percussed it gives out a flat, dull sound and produces a fluctuation or shock at the opposite side of the abdomen. In the upper part of the abdomen over the hollow flank more or less resonance is found. If the animal is made to stand on his hind limbs the saccular dilatation and flatness on percussion are in the region adjoining the pelvis; if held up by its hind limbs they are transferred to the epigastric and hypochondriac regions and the respiration is seriously interfered with; if turned upon his back, the resonance is obtained on the linea alba and at each side, while the percussion dullness is next to the vertebræ. The clearness of the fluctuation is in ratio with the amount of liquid present.
As in other animals, there are anæmia, pale mucosæ, poor condition, thin, dry, unhealthy skin, weak pulse, irritable heart and interference with respiration proportionate to the amount of liquid. The urine is scanty, and there may be diarrhœa.
Diagnosis. From advanced or chronic peritonitis it is distinguished by the history or evidence of diseased liver, heart, or kidney, the absence of hyperthermia or abdominal tenderness, and the absence in the ascitic fluid, extracted with a hypodermic needle, of blood globules, or leucocytes in numbers, of false membranes, of excess of salts, or of a tendency to coagulate firmly.
From overdistended bladder it is diagnosed by its slow, and gradual development, and the change of fluctuation to the most dependent part no matter what position is given to the patient, whereas the tense bladder can be felt through the abdominal walls, extending forward from the pelvis under all circumstances.
From ruptured bladder there is the same distinguishing feature of slow development, the absence of symptoms of uræmic poisoning, of tenderness of the bladder, and of suppression of urine, and also of the urinous odor in the ascitic liquid obtained with the hypodermic needle.
From advanced gestation the differentiation is found in the general diffusion of the swelling and fluctuation, which is not confined as in gestation to the mobile uterine horns, with a series of enlargements each containing a solid nodular fœtus.
From hydrometra and pyometra there are the same pathognomonic differential features of the general diffusion of the swelling among the intestines, and its accumulation in one fluctuating mass at the most dependent part of the abdomen.
Tympany of the bowels causes uniform drumlike resonance, and the swelling does not sag and fluctuate in the lower part of the abdomen.
Abdominal obesity in old dogs gives the rounded swollen abdomen, but there is an entire absence of the pendulous and fluctuating features, and when punctured with the hypodermic needle it furnishes no fluid.
From tuberculosis it is distinguished by the absence of nasal discharge, or of tubercle bacilli in such discharge, or in the ascitic fluid, and the latter inoculated on guinea pigs or rabbits does not cause tuberculosis. The tuberculin test may also be resorted to.
Lesions. The liquid exudate has been found to amount to 30 or 40 quarts in large dogs (Hordt). It is often clear and translucent, of amber tint, though in some cases it is slightly opaque, or reddish yellow. It may remain fluid after extraction or again it may form a loose jelly. It may be red in case of soft tumors or other neoplasms. The liquid is very watery but may contain a considerable amount of fatty globules or granules, and a few epithelial cells and leucocytes. The peritoneum is pale or in advanced cases dull white from fatty degeneration of the epithelium.
Treatment. The first consideration is the removal of the cause. If this is a mere vicious action of the peritoneum, or the presence of a thrombus, or of operable tumor, or even of curable disease of the liver or kidneys, success may be hoped for, while in dilatation of the heart, insufficiency of the cardiac valves, irremediable disease of the lungs, liver or kidney, or malignant or inoperable tumor no such result can be hoped for.
Apart from the removal of the cause the first indication is to evacuate the liquid and this may be done with a large hypodermic needle or small cannula and trochar inserted by preference on or near the linea alba while the animal is in a standing position. Skin and instrument should be rendered thoroughly aseptic, and a bandage should be wrapped round the abdomen and gradually tightened as the liquid escapes. This to a large extent obviates the tendency to faint, or to cerebral anæmia which has caused sudden death in a number of cases. It also to some extent counteracts the sudden effusion of blood in the abdomen, which is at times determined by the sense of vacuity.
Injection of a solution of iodine (tincture of iodine 1 pt., iodide of potassium 1 pt., boiled water 20 pts.) has been employed sometimes with success, but in other cases it has roused a fatal inflammation. It is best adapted to a simple morbid, relaxed state of the peritoneum.
Saline purgatives (sulphate of soda or magnesia) are especially useful in constipated cases and should be pushed in continuous action, as far as the strength of the animal will warrant. By depletion from the portal system they oppose the tendency to mechanical transudation, while by rendering the portal blood more dense they strongly solicit endosmosis from the adjacent peritoneum.
Diuretics have been used extensively and with benefit. They may prove injurious in a kidney that is already the seat of irritation and yet after all be the least of two evils. In some cases instead, the resulting dilution of a dense and irritating urine is directly soothing to the tender kidney. Saltpeter (10 to 15 grs.), acetate of soda (15 to 30 grs.), squills (1 to 2 scr.), may be repeated so as to keep up a free action. Pilocarpine (subcutem) (¹⁄₁₀₆ to ¹⁄₃₀ gr. daily), has removed the ascitic fluid in 14 days (Zahn), but its action is always to be dreaded in a weak system, or with a diseased heart, or lungs.
A supporting bandage on the abdomen is always useful as counteracting the tendency to vacuity and further transudation.
A course of bitters and iron, and a supporting diet, and out door life (sunshine) are important elements in treatment.