The acute congestion attendant on specific microbian infection may be estimated by the increase in weight of the spleen. In the Southern Cattle fever this organ, which is normally 1.45 ℔., is habitually 2 to 5 ℔s., and may reach 8 or 10 ℔s. and in anthrax an equal increase may be noted.
Lesions. In such cases the organ may appear as if there were a simple blood engorgement, and this is largely the case in the early stages, but with the persistence of the disease there occurs an active proliferation of the splenic cells and especially those of the pulp. With the hyperæmia the consistency of the organ is diminished, and still more so with the cell hyperplasia, so much so that in extreme cases rupture may ensue. The color is always darker (purple or blue), but this is only in part due to the abundance of blood and in part to the thinness of the splenic capsule. If the condition persists a hyperplasia of the capsule and trabeculæ ensues, and the condition becomes essentially one of hypertrophy.
Symptoms. In the slighter congestions there are no appreciable symptoms. In the more severe there may be more or less violent colic, but this is usually marked to some extent by the profound depression attendant on the specific fever which is the cause of the congestion. Palpation of the spleen is impossible in the horse. In ruminants it may sometimes be felt along the upper border of the rumen just behind the last rib on the left side. It is soft and yielding retaining the indentation of the finger. If manipulation produces signs of pain it is all the more significant.
Treatment. As a rule this is the treatment of the fever which determines the hyperæmia. Apart from this, laxatives, quinia other alkaloids of cinchona bark, eucalyptus, a current of cold water directed to the region of the spleen, or induction currents of electricity to the same region are also decided stimulants to contraction. Ergot has been used with alleged advantage. In cattle acupuncture of the spleen has been put in practice in anthrax.
CHRONIC CONGESTION OF THE SPLEEN. HYPERTROPHY.
Hypertrophy from chronic congestion, over feeding, hepatic cirrhosis. In horse: from mechanical obstruction in heart, lungs, posterior cava, splenic veins, angioma, from glanders or tubercle in lungs, chronic splenic congestion, disease of splenic plexus. Lesions: increase enormous; mainly of pulp, or largely of fibrous framework. Special neoplasms. Symptoms: excess of leucocytes in blood, eosinophile cells, weakness, anæmia, emaciation, bleeding from mucosæ, stretching, right hypochondriac tenderness, stiff gait, ascites, colic, disorder of the bowels, rectal exploration. Treatment: is that of primary disease; not encouraging; quiniae, eucalyptus, saline laxatives, open air, sunshine, electricity. In cattle is habitually enlarged in Texas fever area. In lymphadenoma increase mainly of fibrous framework and Paccinian bodies, and of adjacent lymph glands. Symptoms: leukæmia, employ palpation, percussion, rectal exploration. Treatment as in the horse. In swine: from high feeding, leukæmia, lymphadenoma, tuberculosis, neoplasms, liver, heart and lung disease. Lesions: great increase of Paccinian bodies, fibrous capsule and trabeculæ. In dog: from traumas, leukæmia and lymphadenoma. Enlarged Paccinian bodies and adjacent lymph glands. Symptoms: leukæmia, many eosinophile cells, abdominal enlargement, palpation, icterus. Treatment: as for large animals.
A continuation of passive congestion from the causes enumerated above, leads to permanent increase of the fibrous reticulum and connective tissue and increase of the splenic pulp. Even the stimulus of a rich and abundant alimentation increases the size of the whole organ, the amount of pulp and the number and development of the Paccinian bodies. Apart from disease the spleens of well fed cattle or horses are always decidedly heavier than those of the starved or debilitated. Of mechanical causes the most potent is cirrhosis of the liver or some other obstacle to the free passage of blood through that organ. The most common causes are, however, the continuous operation of those specific poisons which determine the acute hyperæmias.
SPLENIC HYPERTROPHY IN HORSES.
Causes. It occurs as the result of mechanical obstruction of the posterior vena cava as noticed by Varnell, from obstruction in the splenic artery or veins by Ellenberger and Schütz, as the result of an angioma by Martin, as the result of the morbid hyperplasias in specific diseases—glanders, tuberculosis—taking place in the spleen or lungs and thus directly or indirectly causing chronic congestion of the spleen (Morot, Leisering, Nocard, Varnell) and again as the result of innervation, in disease of the splenic plexus of nerves (Varnell).
Lesions. The increase in size may be enormous (42 lbs. (Bouret and Druille), 92 lbs. (Cunningham), and over 100 lbs. (Girard)). The consistency is varied. There may be such a redundancy of blood and splenic pulp that the capsule is distended to its utmost or even ruptured (Peuch). In other cases the splenic veins have given way and the blood has poured out into the abdomen with fatal result (Crafts, Cunningham, Reis). In other cases the spleen is enlarged, unevenly swollen and indurated by the formation of angioma (Jacob), lymphadenoma, glander or tuberculous nodules. In still others the capsule and fibrous framework are greatly thickened and the substance of the organ has assumed the consistency of the hepatized lung (Rodet).