Alimentary - Stomach & Abomasum Flashcards
4 regions of the stomach
- Esophagus
- Cardia
- Fundus/Body
- Pylorus
Region of the stomach containing only stratified squamous epithelium
Esophagus
Region of the stomach that secretes mucin only
Cardia
Region of the stomach that secretes pepsinogen, HCL & mucin
Fundus / Body
Region of the stomach that secretes mucin & gastrin
Pylorus
Luminal surface of gastric mucous-secreting cells
Foveolar epithelium
Parietal cells secrete:
HCl
Chief cells secrete:
Pepsinogen
Neuroendocrine cells secrete:
Gastrin
What 4 things comprises the gastric mucosal barrier?
- Mucous gel - protects and lubricates
- Bicarbonate (HCO3) - acid neutralization
- Replacement cells
- Blood Flow
What does prostaglandin in the stomach control?
- HCO3 & mucous secretions
- Cell turnover
- Mivrovascular blood flow
Superficial mucosal defect limited to mucosa/lamina propria
tend to bleed less
Erosion
Deep mucosal defect that extends through epithelium into submucosa
tend to bleed a lot
Ulcer
Gastric ulcer sequale
Bleeding
-> anemia
-> internal exsanguination
-> transmural perforation
-> septic peritonitis
-> healing & fibrosis
-> dysmotility or obstruction
-> impaction
Acute gastric ulcer appearance
Red-to-brown mucosal depression with active bleeding +/- fibrin layer
Chronic gastric ulcer appearance
Raised tan “indurated” crater-like lesion with re-epithelialization +/- active hemorrhage
How does a gastric ulcer arise?
Gastric acid secretion overcomes gastric mucosal barrier.
- increased parietal/chief cell secretion
Clinical signs of gastric ulcers
Dog/cat: vomiting, inappetance, abdominal pain, anemia, melena
Cattle: anorexia, decreased milk production, melena, positive grunt test
Horses: anorexia, poor performance, bruxism
Swine: anorexia, peracute death
Common causes of gastric ulcers
- Vascular Compromise (pharmacologic, supraphysiologic stress, displacements)
- Dietary Disturbance
- ** Trauma/Toxin** (FB, caustic)
- Neoplasm
- Infectious/Inflammatory (GASTRITIS)
How do NSAIDs cause vascular compromise & ulcers?
COX (1&2) Inhibition
* Acetylsalicylic acid - PG & TX inhibition
* Carprofen, Deracoxib, Fibrocoxib, Meloxicam - COX2 only
* Acetominophen - TOXIC
How do steroids cause vascular compormise & gastric ulcers?
- PLA2 enzyme inhibition, COX inhibition, alpha-inflammatory
- Decrease immune cell activation
- Induce immune cell apoptosis
NSAID ulcer sequale
COX enzyme inhibition -> decreased PG synthesis
* increased acid secretion (parietal cells)
* decreased HCO3 & mucus
* decreased microcirculation
* decreased replacement cells
True/False
Gastric ulcers can result from gastric displacements and dilations
True
Common gastric displacements and dilations
- Bovine abomasal displacements (LDA, RDA)
- Canine GDV syndrome (CV)
- Equine acute gastric dilation (RUPTURE)
Dietary disturbances causing gastric ulcers
- Canine: dietary indiscretion
- Bovine: milk -> fiber diet in calves, post-parturient diets
- Swine: small feed particle size, bleeding ulcers in pars esophagea -> exsanguination
Neoplasms associated with gastric ulcers
- Adenocarcinoma (K9)
- Squamous Cell Carcinoma (EQ)
- Lymphosarcoma (BV BLV > K9, FE)
- Mast Cell Tumors (typically outside of stomach)
- Gastric neoplasm common in older male dogs
- Glandular portion
- Infiltrative (not often raised)
- Ulcerative (may resemble chronic ulcer)
- Desmoplasia -> firm, tan-white
- Carcinomatosis
- Poor prognosis
Gastric Adenocarcinoma
- Gastric neoplasm common in older horses
- Squamous portion
- Exophytic
- Verrucous
- Ulcerative
- Desmoplasia -> firm, tan-white
- Carcinomatosis
- Uncommon widespread mets
- Poor prognosis
Squamous Cell Carcinoma
- Sporadic gastric neoplasm (more common in intestines) in both small & large animals associated with gastric ulcers
- Abomasum in cows (BLV in older cows), also epidural, retrobulbar spaces, uterus, heart in cows
- Can be associated with FeLV in cats
Lymphosarcoma
(Lymphoma)
Epi-/Norepinephrine mediated VASCOCONSTRICTION is associated with what mechanism of gastric ulcers in dogs?
Stress
COX enzyme inhibition leading to DECREASED prostaglandin is associated with what mechanism of gastric ulcers in dogs?
NSAIDs
Local invasion of neoplastic cells with desmoplasia leading to disruption of glands and microvasculature is associated with what mechanism of gastric ulcers in dogs?
Adenocarcinoma
- Neoplasm associated with pyloric/anterior duodenal ulcers
- Origin in skin, viscera
- Result of excess circulating histamine
Mast Cell Tumors
- Clostridium perfringens culprit causing erosions, ulcers, emphysema, & HEMORRHAGE
- Gram+ anaerobe that produces toxins
- Seen in ruminants, dogs
Hemorrhagic Abomasitis (calves)
Hemorrhagic Gastroenteritis (dogs)
- Type of hypersensitivity reaction seen in dogs, cats, horses
- Infiltration of eosinophils, lymphocytes, plasma cells
- Signs: vomiting +/- diarrhea
- Inflammation causing hyperplasia of mucosa, erosions +/-, loss of gastric glands, fibrosis
Immune-Mediated Gastritis
(IBD)
Eosinophilic Gastritis/Gastroenteritis
