_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.