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.