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.
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).
Symptoms. These are suggestive rather than diagnostic. Most prominent is the condition of the blood with excess of leucocytes and especially of the eosinophile cells. Weakness, emaciation, feebleness of pulse, bloodlessness, bleeding from the nose or other natural passages, are attendant symptoms. In cases of extreme hypertrophy distension of the abdomen is marked and even the enlarged spleen may be made out by palpation, there may be special tenderness and dullness on percussion. Even partial sweats over the region of the spleen (Cadeac), and stretching with the fore feet far in advance (Welsby) have been noted as symptoms. In such conditions the animal walks stiffly, groans in turning, or when suddenly started and is with difficulty urged beyond a walk. There may be ascites, signs of colic, or irregularity of the bowels. Rectal exploration may reveal the hypertrophy.
Treatment is usually the treatment of the primary disease. In glanders, tuberculosis, lymphadenoma, or leucocythemia there is little to hope for. Nor is there much in hepatic cirrhosis, obstruction of the vena cava or valvular disease of the heart. In simple hypertrophy we may resort to quinia or other bitters, eucalyptus, saline laxatives, exercise in the open air and sunshine, and local currents of electricity.
A moderate hypertrophy is the rule in the case of cattle which have passed through the Southern cattle fever, but have continued to live within the area of its prevalence. Gamgee’s observations in 1868 were very conclusive on this point. In over 1,000 western cattle the average weight of the spleen was 1.45 ℔., in 441 Cherokee (Indian Territory) cattle the average was 2.34 ℔s., and in 262 Texas cattle the average was 2.66 ℔s. All these animals were killed for beef, in what was considered to be perfect health. The difference relative to the weight of the entire animal is even greater than is indicated above, for at that date even more than at present, the Texas steer was a small and thin animal in comparison with the portly western bullock.
In lymphadenoma the organ may weigh 24 ℔s. (Tannenhauser); in simple hypertrophy it has been found to weigh 37 ℔s. (Koch). There was usually a marked increase in the size and number of the Paccinian bodies, and hyperplasia of the fibrous reticulum, while the pulp might be deficient and the cut surface rather dry. The adjacent lymph glands are usually enlarged.
Symptoms. Unless in the case of excessive increase, no symptom is usually observable, apart from leucocythæmia. With enormous hypertrophy the enlarged organ may be recognized by palpation, percussion, and perhaps rectal exploration.
Treatment is unsatisfactory apart from the control and arrest of the primary diseases. For simple hypertrophy, bitters, laxatives and electricity may be tried.