*'''[[Gastric Ulceration - all species|Gastric ulceration]]''' - This occurs for three main reasons. First, urea crosses lipid membranes freely and enters the gastro-intestinal lumen of azotaemic animals. The urea is degraded to ammonia by bacterial urease and the ammonia irritates the intestinal mucosa. This is compounded by damage to the blood vessels of the gastric submucosa by the fibrinoid necrosis that is a common feature of uraemia. Elevated serum concentrations of gastrin (which is normally metabolised in the kidney) also lead to excessive production of gastric acid from parietal cells in the stomach. Animals with gastro-duodenal ulceration may show '''anorexia''', '''vomiting''', '''haematemesis''' and [[Peritonitis - Cats and Dogs|'''peritonitis''']] and '''haemorrhage''' if the ulcers perforate. Hypergastrinaemia may also cause incompetence of the pyloric sphincter of the stomach, permitting relfux of irritant bile into the stomach. Similar processes result in the development of '''uraemic colitis'''. | *'''[[Gastric Ulceration - all species|Gastric ulceration]]''' - This occurs for three main reasons. First, urea crosses lipid membranes freely and enters the gastro-intestinal lumen of azotaemic animals. The urea is degraded to ammonia by bacterial urease and the ammonia irritates the intestinal mucosa. This is compounded by damage to the blood vessels of the gastric submucosa by the fibrinoid necrosis that is a common feature of uraemia. Elevated serum concentrations of gastrin (which is normally metabolised in the kidney) also lead to excessive production of gastric acid from parietal cells in the stomach. Animals with gastro-duodenal ulceration may show '''anorexia''', '''vomiting''', '''haematemesis''' and [[Peritonitis - Cats and Dogs|'''peritonitis''']] and '''haemorrhage''' if the ulcers perforate. Hypergastrinaemia may also cause incompetence of the pyloric sphincter of the stomach, permitting relfux of irritant bile into the stomach. Similar processes result in the development of '''uraemic colitis'''. |