Acute gastritis is not uncommonly associated with engorgement of the stomach, and may result from the presence of a foreign body, or from the action of irritant poison on the lining membrane. It is also shown to arise sometimes in the course of one or another of the contagious fevers. Of the irritant poisons inducing gastritis in a horse, only a few are likely to be taken voluntarily in the food, or from a spirit of mischief or curiosity, or to be given out of ignorance or malice by attendants. These are the salts of copper, zinc, mercury, lead, and arsenic; the last named being the most frequently met with, as it is easily obtained in large quantities in the form of sheep "clips" despite the arsenic acts and pharmacy laws, which afford altogether insufficient protection to the stock-owner. Of the poisonous plants, the leaves and shoots of the yew and rhododendron are not uncommonly the cause of gastritis.
In this disease acute abdominal pain continues without intermission, and there is but slight diminution of intensity save for short periods. The pulse is small and hard, the breathing quickened, and the expression anxious and miserable. The mucous membranes of the eyes and nose are intensely reddened, profuse sweats break out, and the animal looks back towards the flank. These symptoms are common to gastritis from any cause, but there are certain others special to inflammation of the stomach when induced by irritant poisons. In the case of arsenic, the most common are intense thirst and frothing at the mouth. The lips are sometimes swollen and pendulous; there is restlessness and excitement, hurried breathing, and a small and maybe imperceptible pulse. The muscles quiver, and the body is suffused in sweat, and the breath gives out a foetid odour. Paroxysms of pain recur again and again, and death follows in great agony.
When the disease is dependent upon yew poisoning it is usually associated with great nervous prostration and collapse, and a fatal termination quickly follows the ingestion of the poison.
To arrive at the cause, if possible, should be our first care, as upon this the treatment will greatly depend. If it is found to result from engorgement of the stomach, or from irritation of foreign bodies swallowed with the food, treatment will consist in the administration of soothing and demulcent remedies, as linseed-tea, barley-water, or milk, together with a mixture of powdered gum-arabic, bismuth, and hydrocyanic acid; the latter are particularly effective in some cases; and if the acute symptoms abate, a long and careful regime must be observed before a stomach thus injured can take upon itself the digestion of ordinary foods, as hard corn and hay. A gradual upward scale of dietary, from linseed-tea and slops, bread, meal, carrots, mashes, and green meat, may lead to a moderate allowance of steeped or scalded corn, and finally oats and hay.
When an irritant poison has been taken and its nature has become known, direct antidotes should first be administered. A list of these will be found in a subsequent chapter, where the individual in search of a remedy has been supplied with information for his guidance until the services of a qualified veterinary surgeon can be procured; and as cases of this description require special care and treatment, no time should be lost in securing veterinary aid, while such antidotes as are at hand may be profitably administered pending his arrival. Eggs, with linseed-oil and gruel, may be beaten up and given in the interval of waiting, or in the absence of these, milk, linseed-tea, or a solution of gum-arabic.
The rarity of vomition in the horse, elsewhere referred to, and the all but impossibility of exciting it artificially, deny us one of the chief aids available to the human surgeon, who will hasten to empty the stomach of any remaining poison either by means of an emetic or the stomach-pump. In the case of the horse, however, we are compelled to rely on the action of chemical antidotes to neutralize the poison, and on physiological agents to control its action.
Abdominal pain, which is a leading feature of the affection, should be met by the employment of hot compresses over the region of the stomach - blankets or sheets dipped in hot water (the naked elbow should be the test of temperature) and covered with waterproofs, as loin cloths, to retain the moisture and keep the parts continuously steamed. The intestinal track must be cleansed of the pernicious matter, but not by any heroic remedies; small doses of oil, linseed or castor oil, emulsified by whipping with mucilage, will answer the purpose.