Gastric ulcers in horses are erosions or lesions in the lining of the stomach, caused when the stomach’s protective mechanisms fail to defend against acidic gastric juices. Factors that reduce the ability of the mucosal lining to resist the acidic effects of gastric juice (a mixture of digestive enzymes and hydrochloric acid) can lead to ulcer formation. If the lesion extends through the intrinsic layer of muscle of the mucosa into the tissues below, it is known as an ulcer.
What Factors Contribute to Gastric Ulcers in Horses?
Ulcers are produced when external factors reduce the ability of the mucosal lining to resist the acidic effects of gastric juice. The mucosa elsewhere is less well protected, and its breakdown may lead to ulceration.
How Do Medications Like NSAIDs Affect Ulcers?
Long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) is one of the two major causes of ulcers. Withdrawal of NSAID treatment usually allows the ulcer to heal.
How Does Bacterial Infection Cause Ulcers?
Infection with Helicobacter pylori is the most common bacterial infection in humans. This bacterium converts the abundant waste product urea into carbon dioxide and ammonia. The process causes the mucosal lining to break down. In its weakened condition, the lining cannot withstand the corrosive effects of gastric acid, and an ulcer can form.
What Role Does Stress Play?
In special circumstances such as the state of shock produced by large burns, intracranial surgery, coronary occlusion, and septicemia, acute and rapidly penetrating ulcers may occur.
What Are the Symptoms and Complications?
Pain is the major symptom of ulcers. The pain is a burning or gnawing sensation felt in the midupper abdomen. Gastric ulcers almost always recur in the same site within the stomach.
What Happens if an Ulcer Bleeds?
Bleeding may be obscured because of oozing from the floor of the ulcer and detectable only by laboratory testing of the feces, or bleeding may be brisk, leading to the passage of tar-coloured stools (melena). Occasionally, when the ulcer erodes into a large vessel, bleeding is excessive and life-threatening.
What Are the Treatments?
Surgery for chronic ulceration is used less frequently since the introduction of drugs that stop the secretion of stomach acid. Histamine-receptor antagonists, such as cimetidine, ranitidine, and famotidine, block the action of histamine on the acid-secreting parietal cells of the stomach. Proton pump inhibitors, such as omeprazole, lansoprazole, and rabeprozale, inhibit the ATPase enzyme inside the parietal cell and prevent acid secretion. Treatment for H. pylori–induced ulcers are antibiotics and a proton pump inhibitor.
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