In the more intense forms all symptoms are aggravated. There is anorexia and even refusal of water, dullness and prostration are well marked, the head carried low, and the gait is unsteady. The mouth is hot with tenacious mucus, and a fœtid odor; the tongue is furred and red at the tip and margins, the eye is sunken, the conjunctiva icteric, the face pinched, and the pulse accelerated. Hyperthermia may reach 104° F. Breathing may be almost normal, or with fever, may become rapid and accompanied by a pleuritic ridge on the flank. The back is slightly arched and rigid, the belly drawn up and tender, after meals it may be tympanitic, and colics set in or are aggravated, pawing, uneasy movements of the hind limbs, and lying down to rise again shortly, with frequent looking at the flanks being noticeable.
Defecations are at first abundant and coated with mucus, later the balls are small and scanty and expelled with much effort. From the first the everted rectum is of a very deep red. Toward the end of the first day or later the intestinal rumbling increases, flatus passes freely, and diarrhœa may set in and prove critical. This usually indicates disease in the colon and tends to recovery; it may be entirely absent if the inflammation is confined to the duodenum, the effused liquid being re-absorbed from the cæcum and colon. If the diarrhœa should prove critical there is a return of appetite and spirit, the fæcal discharges become firmer and recovery takes place in a week. If, however, the diarrhœa becomes more profuse and bloody, the colics more intense, the eyes more sunken and hopeless, the face more pinched and anxious, and the temperature reduced to or below the normal, with great weakness and debility, the near approach of death may be feared. This state of collapse may be further marked by extreme coldness, or dropsy of the limbs, increased icterus, hurried breathing and rapid loss of flesh.
A prominent icterus indicates implication of the liver from the ascent of the infecting germs through the bile ducts, or the passage of microbes or their products or both through the portal vein. In either case it is a serious complication.
Prognosis. In its uncomplicated form the disease is not very fatal to vigorous, mature horses, though more trying to the young. If infective germs or their products implicate the liver producing marked jaundice, or if the general system is poisoned by the microbes or their toxins, producing marked depression and prostration the danger is enormously enhanced.
Treatment. In the mildest cases a limitation of the food to moderate bran mashes, and a dose of ½ lb. of sodic sulphate, with salicylate of soda (3–4 drs.) or bismuth will usually suffice.
In severe cases, at the outset, while constipation exists give 3 or 4 drs. of cape aloes, or ½ lb. Glauber salts or ½ pint olive oil, combined with 2 drs. of extract of hyoscyamus or belladonna and 3 drs. salicylate of soda. This serves to deplete from the inflamed vessels and the whole portal system, to soothe suffering, to expel much of the offensive and infective matters from the bowels, and to check fermentation in that which remains. They should be given with, or followed by mucilaginous liquids like solutions of slippery elm or gum arabic, flaxseed tea, or well boiled farinaceous gruels.
Pilocarpin, 3 grs., or eserine, 2 grs., or both have been recommended and may be resorted to when action of the bowels is urgently demanded. They need not supersede the other laxatives. In manifest impaction of the large intestines, salts, aloes, pilocarpin and eserine may form an effective combination.
Copious enemata with mucilaginous liquids or warm soap suds should be given at frequent intervals.
Counter-irritants and derivatives to the abdomen are most important. Hot fomentations may be persisted in for an hour at a time, or a damp compress around the abdomen covered closely by dry blankets and held in place by elastic circingles. Mustard pulp made with cold water rubbed in against the hair and at once covered by paper and a thick blanket is often of great value as drawing blood and nervous action to the skin and relieving the suffering intestine.
In all cases the diet and drink must be carefully supervised. A little thoroughly scalded wheat bran, or farina, and decoctions of flaxseed, farinas, slippery elm or mallow, or a solution of gum arabic will refresh the animal without overloading the digestive organs or favoring further fermentation.