The atonic bowels are always the seat of extensive fermentations and tympany. The microbes engaged in these fermentations and their toxins, are accountable for toxic changes occurring in the locally diseased parts and in distant organs. To this may be attributed the congestion and softening of the liver and the engorgements and hemorrhagic centres in the spleen.
Symptoms. An animal, perhaps known to harbor the sclerostoma equinum, is suddenly attacked with violent and persistent colic. He trembles, paws, moves his hind feet uneasily, kicks the abdomen, throws anxious looks at the flanks, crouches, lies down, rolls, gets up, and at once gets down again. The intensity of the suffering rapidly increases, the face is drawn and pinched, the eye is extremely anxious, the patient no longer lies down, but throws himself down reckless of consequences, when down he is not quiet for an instant, but now on his breast, then on his side, then on his back, the limbs struggling and jerked violently, the head turned first to one side and then to the other, he is a picture of extreme agony. If made to walk the same indications continue; he walks with head down and limbs semiflexed ready to drop at any moment, and often he will drop suddenly in spite of every effort to keep him on his feet. The pulse is at first strong and full, but as extensive effusion takes place into the bowels or abdomen, or as the animal is poisoned by toxins, it becomes small, weak, and it may be imperceptible. Breathing is quick and catching, and the mucous membranes are dark red. Sweating which shows first about the elbows or flanks or back of the ears finally becomes general, the surface cold and the limbs especially so. Fæces may be passed at first, a few dry balls at a time from the floating colon or rectum, but soon they are suppressed entirely. Some patients strain frequently to micturate but pass little at a time.
In some instances the acute pain seems to suddenly cease, but there is no general improvement, the patient stands with head depressed, eyes sunken and expressionless, ears lopped, cold perspiration, chilly limbs, unsteady gait and imperceptible pulse. It implies merely a paralysis of the affected bowels in connection with the extensive congestion and extravasation.
Course. Duration. The more acute cases reach their acme with great rapidity, death may occur after two hours illness, and in other cases it may be delayed ten or even twenty-four hours. It may be caused by indigestion and tympany, by volvulus or invagination, by excessive hemorrhage, or by poisoning with toxic matters.
Recovery occurs when the vessel blocked is an unimportant one as a branch of the left bundle so that circulation may be reëstablished from collateral trunks; or when a more important trunk has been but partially blocked, and after a time it either clears itself, or collateral circulation comes in with sufficient compensation. There is a more or less rapid disappearance of the colics and other symptoms, a free passage of urine, the rejection of fæces, it may be in a liquid, semi-liquid or sanguineous condition, yet enough to indicate the restoration of intestinal tone. The patient begins to pick morsels of food and soon acquires his former appetite.
In some instances, however, the recovery is not complete. Trasbot has noted a case of laminitis occurring within fifteen hours after the improvement, and in other cases there remain chronic debility and catarrh of the intestines. The appetite remains poor, there are occasional colics, the bowels are irregular, loose or costive, and the fæces are dry, glossy and covered with mucus. The back is arched, the belly tucked up, strength and vigor are both lacking, and the patient spends much time in the recumbent position.
Complications of various kinds may follow as in other diseases of the intestines. After even the best recoveries, a relapse is always to be apprehended as the original cause remains and the animal is liable to be cut off at any time.
Treatment. This is very unsatisfactory as the original source of trouble, the worms, being in the blood-vessels, cannot be reached by vermifuges that would be harmless to the host, and clots blocking the smaller intestinal vessels, cannot be dissolved and removed. Moreover, although we could compass the death of the worms in the aneurisms, we would leave their dead bodies as sources of septic change, blood coagulation and embolism.
A certain number of cases, however, are not necessarily fatal, and the worms of the blood-vessels have not an indefinite period of life, so that there is some encouragement for both therapeutic and preventive treatment. During the attack we must be content to treat symptoms. French veterinarians still trust largely to general bleeding, adopted at the very outset and to the extent of 6 to 10 quarts. It will temporarily lessen the vascular tension, more permanently dilute the blood, and calm nervous excitement, and in the most violent cases, as a kind of forlorn hope, it might be tried with the view of tiding over the acute stage until a freer collateral circulation could be established.
The use of anodynes will be more generally acceptable to American practitioners. Two to four grains of sulphate of morphia or codeine may be given hypodermically in combination with 1½ gr. eserin, 7 grs. barium chloride, or 2 grs. pilocarpin, to secure a speedy movement of the bowels.