Ch 91 - Stomach Flashcards
List the secretory cells of the stomach and what each produced
- Parietal (Body) - Acids and intrinsic factor (mucosal protein which binds B12 to allow its absorption in distal SI
- Mucous Neck (Body, Antrum) - Mucous
- Chief (Body) - Pepsinogen
- Epithelium - Mucous, bicarb
- Endocrine (Body) - Histamine, Gastrin, Serotonin
What is contractile retropulsion?
Pyloric closure prior to full antrum contraction, allowing liquid chyme to pass through but >2mm large solids are forced retrograde back into body. Results in breakdown of digestible particles to 0.1-0.63mm prior to gastric emptying
By what process does gastric mucosa and submucosal ulcers heal?
- Mucosa - Epithelial regeneration
- Submucosal - Fibrotic repair
What tissues contribute to collagen formation in the stomach?
Fibroblasts and smooth muscle cells of the GIT
What are some negative effects of pre-surgical fasting?
What recommendation may be more appropriate?
- Decreased gastric pH
- Higher incidence of gastrooesophageal reflux
- Does not reliable decreased gastric content volume
Small amounts of canned food 3hr beore surgery may decreased gastric acidity and minimise occurance and clinical impact of gastrooesophageal reflux while having minimal to no impact on gastric content volume
What anaethetic drugs can be used to decreased gastric secretion?
Anticholinergics such as atropine and glycopyrrolate
What ligaments can be transected to aid in visualisation of the dorsal aspect of the stomach?
Hepatogastric and hepatoduodenal ligaments
Tomihata et al: What were the half lived of polyglyconate (Maxon), poliglecaprone 25 (Monocryl) and polydioxanone (PDS) in gastric juices?
- Polyglyconate - 75d
- Poliglecaprone 25 - 15d
- Polydiaxonone 12d
List some methods of determining gastric wall viability
- Gastric wall thickeness
- Serosal colour
- Serosal capillary perfusion
- Peristalsis
- If questionable, seromuscular layer can be incised to assess arterial supply
Subjective criteria have an 85% accuracy
What is the ideal closure method after partial gastrectomy?
2-layer inverting pattern (if lumen diameter allows)
Benitez et al: What was the reported recurrence of GDV after incisional gastropexy?
0% in 61 dogs
- Equivalent to belt-loop and superior to circumcostal and gastrocolopexy
What blood supply is incorporated when creating a belt-loop flap in the stomach for gastropexy?
Based on the greater curvature of the stomach with incorporation of branches of gastroepiploic artery
Flap approx 4cm long and 3cm thick
Which part of the stomach is the base for a circumcostal flap for gastropexy?
Lesser curvature
(Opposite to belt-loop)
What is the recommended port placement for laparoscopic gastropexy?
Three portal technique, all on ventral midline
- 1cm caudal to umbilicus
- Instrument port 3-4cm caudal to xyphoid
- Final port midway between first 2, directed medially towards proposed gastropexy site
List the options for pyloroplasty
Fredet-Ramstedt Pyloromyotomy
- Longitudinal incision through serosa and muscularis extending 1-2cm orad and aborad of the pylorus
- Allows protrusion of submucosal surface to protrude and enlarge
- Use limited - restriction must be limited to the serosa or muscularis layer
Heineke-Mikulicz Pyloroplasty
- Full thickness longitudinal incision centred on the pylorus and closed transversely
Y-U Pyloroplasty
- Y-shaperd full thickness incision with arms over the antrum/pylorus and body extending through pylorus and onto duodenum
- U-flap pulled aborally to close as a U
What is a Billroth I?
Pylorectomy and gastroduodeno anastomosis
What structures must be identified and protected during a pyloroectomy?
- Bile duct
- Pancreatic ducts
- Vascular supply to the stomach and duodenum
What is the prognosis of gastroduodenostomy (Billroth I)
Study of 24 dogs:
- 18 survived 14 days
- 10 died by 3 months
- Hypoalbuminaemia (62.5%), anaemia (58.3%)
What is a Billroth II?
Partial gastrectomy with gastrojejunal anastomosis
- Side-to-side anastomosis
- Cholecystoenterostomy usually required
- Prognosis very poor…
List the 4 types of hiatal hernias
- Type I: “Sliding” - Intermittent movement of gastrooesophageal junction into the thoracic cavity
- Type II: “Paraoesophageal” - The gastrooesophageal junction remains in a normal position and a portion of the fundus herniates beside the oesophagus
- Type III: Combination of I and II
- Type IV: Herniation of abdominal organs other than the stomach
What breeds are overrepresented for type I hiatial hernia?
- Shar Peis
- Bulldogs
List potential medications used in the medical management of hiatal hernia
Reducing acid secretions
- H2 receptor blockers: ranitidine, cimetidine, famotidine
- H/K-ATPase inhibitor omeprazole
Oesophageal protection
- Sucralfate (polyaluminium sucrose)
Prokinetics
- Metoclopromide or cisapride (increase gastric emptying and enhance lower oesophageal tone)
Diet
- Low fat diet fed more frequently or from elevated height
8/15 dogs had complete resolution with medical management
What are the main components of surgical correction of a hiatal hernia?
- Phrenoplasty
- Oesophagopexy
- Left-sided gastropexy
Prognosis is good!
What is gastrooesophageal intussusception?
What breed is overrepresented?
- Retrograde (orad) invagination of the stomach into the oesophagus without displacement of the gastrooesophageal junction
- GSD are overrepresented (over 50% of cases)
- More than 75% were in dogs younger than 3 months
What is the recommended treatment of gastroesophageal intussusception?
What is the prognosis?
- Ventral midline coeliotomy with reduction of intussusception and left sided +/- right sided gastropexy
- Mortality rate 95% in a study of 22 dogs from 1984…
- More recent individual case reports are more promising
What is the hypothetised cause of hypertrophic pyloric gastropathy (pyloric stenosis) in brachycephalic breeds?
Chronic air dilation of the stomach cause increased intragastric pressure, secondary secretion of gastrin and gastric acid, resultant production of cholecystokinin and secretin which have a trophic effect on the antral and pyloric mucosa
What percentage of gastric FB may be visible on plain rads?
95%
What is the most common form of gastric neoplasia in the dogs?
What breeds are predisposed?
What is the reported metastatic rate?
What are the three morphological forms?
- Gastric adenocarcinoma (42-90%)
- Belgian Shepherd, Rough-coated Collie, Staffys
- Metastatic rate 70%
Three forms:
- Diffuse infiltration (“Linitis Plastica”) - non-distensible, scirrhours stomach wall
- Groups of ulcerated mucosal plaques
- Discrete polypoid mass
What are gastrointestinal stromal tumours (GIST)?
- Arise from the cells of Cajal
- c-kit positive (differentiates them from lyomyosarcomas)
What is the most common form of gastric neoplasia in cats?
What is the prognosis?
- Gastric lymphoma
- Prognosis depents on grade. Low grade can have good prognosis with chemotherapy with MST 704d
- Intermediate- and hihg- grade usually rapidly progressive and fatal
What is the prognosis of gastric neoplasia in dogs?
Poor…
- 2/21 dogs lived longer than 9 weeks with combo of Bilroth I/II, partial gastrectomy or no treatment
List some causes of gastric ulceration
- Renal and hepatic disease:
Decreased hepatic degradation of gastrin and histamine
Derangement of mucosal bloodflow due to portal hypertension and thrombosis
Decreased renal clearance of gastrin? - NSAIDs and glucocorticoids
COX-inhibition resulting in decreased PG production resulting in decreased mucosal bloodflow, epithelial mucous production, bicarb secretion and epithelial turnover.
Direct topical effect of weakly acidic and lipid-soluble NSAID on gastric mucosa - Gastrinoma
- Systemic mastocytosis
List the main options for medical management of gastric ulcers
Histamine (H2) Receptor Blocker
- Cimetidine, ranitidine, famotidine
Proton pump inhibitors
- Omeprazole, pantoprazole (substituted benzimidazoles that covalently bind H/K-ATPase enzyme, blocking its activity
- Absorbed in alkaline environment (proximal duodenum)
- Administed 1hr before a meal
Sucralfate
- In acidic environment dissociates. Octasulphate portion forms a thick paste that binds electrostatically charged proteins in the base of ulcers
- “Biological bandaid” - protective barrier, inactivates pepsin, absorbs bile acids, stimulates local PG release
Misoprostal
- SYnthetic analogue of PGE1
- Increases bicarb secretion, mucous production and mucosal bloodflow
- Decreased H/K-ATPase pump activity via decreased intracellular cAMP
- Can help to prevent ulcer formation but does not have an effect on treating current ulcers
What is a gastrinoma?
A non-beta pancreatic islet cell tumour, that stimulates with hypersecretion of gastrin from the antral G cells, resulting in gastric hyperacidity and ulceration
In what percentage of cases does gastroscopy confirm gastric perforation in dogs and cats?
Only 17%
What percentage of dogs have ECG abnormalities during GDV?
40-70%
What outcomes have been associated with lactate concentration?
- Plasma lactate over 6mmol/L 88% specific and 61% sensitive for gastric necrosis. In same study, 99% of dogs with lactate below 6 survived vs 58% above 6
- Beer et.al. Initial lactate cutoff 7.4mmol/L 82% accurate (50% sen, 88% spec) for gastric necrosis and 88% accurate (75% sen, 89% spec) for predicting outcome
- 90% of dogs with initial lactact or 9.0mmol/L or less survived
- Survival rates significantly increased in dogs with final lactate 6.4 or less (91% survival), absolule change in lactate of 4mmol/L or more (86% survival), percentage change in lactate of 42.5% or more (100% survival)
What are the reported recurrence rates of GDV with an incisional, circumcostal or gastrocolopexy gastropexy?
- Incisional: 0%
- Circumcostal: 4.3%
- Gastrocolopexy 3/20 (15%)
List factors which have an association with an increased mortality rate with a GDV
- Clinical signs for more than 6hr
- Gastrectomy
- Splenectomy
- Hypotension
- Gastric necrosis
- Pre-op arrhythmias
- Peritonitis
- Sepsis
- DIC
Overall survival 73-90%
How can myoglobin be used as a prognostic indicator for GDV?
Myoglobin cutoff of 168ng/ml was 60% sensitive and 84% specifice for predicting survival
- 90% below cutoff survived
- 50% above cut off died
What is the lifetime risk of dogs predisposed to the development of GDV?
4-37%
How do stapled laparoscopic gastropexies compare to open incisional gastropexies?
Stapled were significantly weaker at 7 days after surgery but were not different in mean tensile load to failure at 30 days post-op
