Gastric Disease Flashcards
What are the major intrinsic factors promoting ulcer formation in the stomach?
- hydrochloric acid (predominant factor)
- bile acids
- pepsin (pepsinogen secreted by chief cells - converted to pepsin in an acidic environment pH < 3)
What are the intrinsic factors protecting against ulcer formation in the stomach?
- mucus-bicarbonate layer
- maintenance of adequate mucosal blood flow
- mucosal prostaglandin E2
- epidermal growth factor production
- gastroduodenal motility
What is the normal pH of equine gastric contents?
- variable from < 2 to > 6
- dependent on dietary state (fasted vs fed)
What are the predominant stimuli to hydrochloric acid secretion in the stomach?
- gastrin (released by G cells in antral mucosa; release controlled by gastrin-releasing peptide which is stimulated by gastric distension and increased luminal pH)
- histamine (released by mast cells and ECL cells in the gastric gland)
- acetylcholine via the vagus nerve
What are the factors that inhibit gastric acid secretion in the stomach?
- somatostatin (released by fundic and antral D cells)
- epidermal growth factor (EGF), a peptide produced in saliva
What is the predominant mechanism responsible for squamous mucosal ulceration?
- excessive acid exposure
What is the prevalence of ESGD and EGGD?
- prevalence varies with breed, use, level of training as well as between ESGD and EGGD
- highest prevalence of ESGD occurs in TB racehorses; 37% untrained, increasing to 80-100% within 2-3 months of training
- prevalence of EGGD less well understood
Where are the majority of EGGD lesions located?
pyloric antrum
Are breed, age or sex associated with the presence of ulceration?
- other factors such as intensity or duration of exercise outweigh any potential age or sex effect
- breed effect may be present with TBs predisposed to ESGD
What are the nutritional risk factors associated with ulceration?
- forage type - increased starch/grain intake
- increased time between forage feeds (>6h) compared with more frequent forage feeding (<6h) increases the likelihood of ESGD
- intermittent access to water
- intermittent starvation causes and increases the severity of ESGD
- NB. fasting model poorly reflects multifactorial nature of gastric disease
List the main clinical signs associated with EGUS
- colic (postprandial; possibly due to altered GIT motility)
- reduced appetite (mild to severe)
- poor body condition
- behavioural effects (inconsistently reported)
- poor performance - direct consequence of gastric pain?; other factors need to be considered
- differences in clinical signs between ESGD and EGGD unknown
- NB. wide variety of clinical signs may be present but they are nonspecific and poorly associated with presence of EGUS
Which age group is more commonly affected by gastroduodenal ulcer disease (GDUD)
- suckling and early weaning foals
What are the potential complications of GDUD?
- gastric or duodenal rupture
- pyloric or duodenal stricture
- ascending cholangitis
- severe squamous and oesophageal ulceration and aspiration pneumonia can occur secondary to gastro-oesophageal reflux
List the causes of primary gastric dilation
- gastric impaction
- grain engorgement
- excessive water intake after exercise
- aerophagia
- parastism
List the causes of secondary gastric dilation
- (more common than primary dilation)
- primary intestinal ileus
small or large intestinal obstruction
