Stomach and Abomasum Pathology Flashcards
Pyloric stenosis/ Pyloric muscular hypertrophy
Tonic stenosis of the pyloric sphincter: myenteric plexus or gastrin excess
Common in dogs, rare in cats and horses
What does pyloric stenosis look like in dogs?
Hypertrophy of the pyloric smooth muscle (muscular thickening)
Effects pyloric stenosis
Delayed gastric emptying
Obstructs pyloric outflow
CS of pyloric stenosis
Vomiting of food several hours after a meal
Poor weight gain
Aspiration pneumonia
Depression and dehydration
Gastric dilation in horses
Secondary to obstruction
Grass sickness (Datura forex seed with parasympatholytic alkaloid- bloat)
Pathogenesis of grass sickness
Consumption of excess fermentable carbs → gas production by bacteria → organic acids (lactic acid)
Influx of water due to ↑ osmotic pressure → severe distention → systemic dehydration
Gastric rupture in horses
Follows primary or secondary dilation
Occurs along greater curvature parallel to the omental attachment
Volvulus
Twisting of the intestine on its mesenteric axis
Left colon in horses
Luminal and vascular compromise → obstruction and infarction
Torsion
Rotation of a tubular organ along its long axis
Similarity between torsion and volvulus
Both compress mesenteric veins and arteries → ischemia obstruction
Displacement of large colon in horses
Loop of bowel is only fix at its base
Cecum, transverse colon, route of mesentery- lack of attachments → displacement and torsion
Gastric Dilation and Volvulus (GVD)
Associated with eating (aerophagia) in dogs
In deep chested breeds like Danes, Bernards, setters, wolfhounds
Predisposing factors of GVD
↑ laxity of the hepatogastric ligament, splenectomy, small particle feeds
Kenneling, raised feed bowel, reversed sneezing from nasal mite Pneumonyssoides caninum
Recurrent dilation with overfeeding, postprandial exercise and hereditary disposition
GDV Pathogenesis
- Dilation of the stomach by gas, fluid and feed
- Rotation is 180-360 degrees of stomach clockwise its mesenteric axis (volvulus)
- Obstruction of cardia that prevents eructation and emesis
- Obstruction of the pylorus that prevents passage of gastric content into SI
What does GDV lead to?
- ↓ venous return via portal vein and caudal vena cava
- Reduced perfusion of intra abdominal organs
- Reduced cardiac output and circulatory shock/ collapse
Incidence of GDV
Incidence of GDV ↑ with age and weight
Gross changes associated with GDV
Severe abdominal distention
Clock-wise rotation on a ventrodorsal axis
Hemorrhagic venous infarction
Rupture of the stomach
V-shaped bending of enlarged spleen
Congestion, hypoxia, infarction of intestines and pancreas
How does GDV affect the pancreas
Myocardial depressant factor
↓ contractility of the heart
Left dorsal colon displacement
Entrapement by spleen and body nephrosplenic or phrenicosplenic ligament
Gastric volvulus in swine
Sudden death in adult sow
Excitement and anticipation of feeding after long interval
Rapid ingestion of feed, water and air
Cs of gastric volvulus in swine
Anorexia → abdominal distention → dyspnea and drooling
Abomasal displacement
Common in high producing dairy cattle (older animals) @ time of parturition
Commonly ventral and left- suspended loosely by the greater and lesser omentum on ventral part of the abdomen
Sequelae to LDA and RDA
Ulceration and fibrous adhesions
Venous infarction
Peritonitis
15% of are right displacements which often progress to _________
Abomasal volvulus
What does severe volvulus cause?
Obstruction of BV to the omasum and trauma to vagus nerves
Gastric/ abomasal impaction causes
Low quality roughage , low water intake, poor mastication
Vagal nerve damage, pyloric stenosis
What does gastric/ abomasal impaction cause
Hypochloremia, hypokalemia, metabolic alkalosis
Abomasal emptying defect (Suffolk sheep)
Gastric Ulcers etiologic factors
Idiopathic
Local mucosal injury
Steroids and NSAIDs
Diet, infections uremia
Helicobacter
High gastric acidity causing gastric ulcers
Mast cell tumors (histamine) → stimulates HCl secretion through release
Zollinger- Ellison syndrome (hypergastrinemia) → pancreatic gastrinomas
Steroids/ NSAIDs causing gastric ulcers (aspirin)
Interference with PG synthesis: PGE2 and PGI2
Direct epithelial necrosis
Foal gastric ulcers
Common (idiopathic)
1/2 foals under 4 months
Squamous mucosa
Stress
Equine gastric ulcers
Gastric ulcer syndrome (glandular stomach- pylorus)
40-90% of competitive and performance horses
NSAIDs (phenhybutazone)
Gastric ulcers in pigs
Common with severe hemorrhage and anemia
Penned pigs fed finely ground grain or pellets
Stress, heat, inconsistent feeding
What do gastric ulcers affect in pigs?
Stratified squamous epithelium
Esophageal portion of cardia
Fermentative commensal bacteria: Lactobacillus, bacillus
Gastric ulcers in dairy cow
Heavy grain feeding (lactic acidosis)
Parturition
Displacement of the abomasum and BVD
What is subsequent to gastric ulcers in dairy cows?
Chronic perforation (omentum seals abomasal ulcers)
Large perforation occurs → septic peritonitis
CS of gastric ulcers
Anemia secondary to gastric bleeding
Melena (digested blood in feces)
Coffee ground like material (hematemesis)
Uremic Gastritis (uremic gastropathy)
Congestion and edema of gastric mucosa caused by injured capillaries within the lamina propria
Assoc. with ↑ conc. of nitrogen derived metabolic waste
Chronicity of uremic gastritis
Mineralization of gastric mucosa
Fine white stippling and lines in the mucosa
Squamous cell carcinoma (horses)
Hypercalcemia
Hypophosphatemia
Paraneoplastic production of PTH-rp
Adenocarcinoma (dogs, siamese cats)
Ulcerated plaques or nodules
Marked scirrhous rx (desmoplasia)
High metastatic potential (70% dogs diagnosed)
Other gastric neoplasias
Adenomas
Leiomyomas and leimyosarcomas
Lyphoma
Bovine leukemia virus
Where are gastric neoplasias common
Abomasum, right atrium, LNs and uterus
20% of ________________ develop in the stomach
K9 GI mast cell tumors
Chemical gastritis
Diffuse gastric congestion
Hemorrhage, ulceration, necrosis
What causes chemical gastritis
Arsenic, thallium, formalin
NSAIDs
Blister beetle horses
Blister beetles
Cantharid toxin
Few beetles enough to kill a horse
Causes ulceration of GI and urinary track, myocardial necrosis
