Stomach Flashcards
(19 cards)
The consistently largest artery to the stomach is the
Left gastric
- arises directly from the celiac trunk and divides into an ascending and descending branch along the lesser gastric curvature
- 20%, the left gastric artery supplies an aberrant vessel that travels in the gastrohepatic ligament (lesser omentum) to the left side of the liver
Which of the following inhibits gastrin secretion
Acid
- Luminal peptides and amino acids are the most potent stimulants of gastrin release
- Luminal acid is the most potent inhibitor of gastrin secretion
- the latter effect is predominantly mediated in a paracrine fashion by somatostain released from antral D
- ACh released by the vagus nerve leads to stimulation of ECL cells, which in turn produce histamine
Helicobacter pylori primarily mediates duodenal ulcer pathogenesis via
Antral alkalinization leading to inhibition of somatostain release
- Urease, which converts urea into ammonia and bicarbonae, thus creating an environment around the bacteria that buffers the acid secreted by the stomach.
- decrease level of somatostain, somatostain messenger RNA production and fewer somatostain producing D cells
The effect of erythromycin on gastric emptying is through its function as a
Motilin agonist
- common prokinetic agent used to treat delayed gastric empting and works as a motilin agonist
- Domperidone and metoclopramide = dopamine antagonist
- Metoclopramide = 10 mg PO qid
- Erythromycin - 250mg PO qid
- Domperidone 10 mg PO qid
Secreted by gastric parietal cells
Intrinsic factor and HCl
- intrinsic factor binds to luminal vitamin B12 abd the compelx is absorbed in the terminal ileum via mucosal receptors
- Vitamin B12 deficiency can be life threatening and patients with total gastrecnomy or pernicious anemia require B12 supplementation by a nonenteric route
The most accurate diagnostic test for Zollinger-Ellison syndrome is
Secretin Stimulation test
- an IV bolus of secretin stimulation (2 U/kg) is given and gastrin levels are checked before and after injection.
- An increase in serum gastrin of 200 pg/ml or greater suggests the presence of gastrinoma
- Patients with gastrinoma should have serum calcium and PTH levels to rule out MEN1
Preoperative imaging study of choice for gastrinoma
Somatostatin receptor scintagraphy
- the octreotide scan
- Gastrinoma cells contain type II somatostain receptors that bind the indium-labeled somatostain analogue (octreotide) with high affinity, making imaging with a gamma camera possible
Patients taking NSAIDs or aspirin need cocomitant acid suppressing medication if these are present
- Concurrent steroid intake
- >60 years olf
- concurrent anticoagulant intake
- prior GI event
The optimal initial managemnt of a patient hospitalized for a bleeding peptic ulcer
Intravenous PPI
- 75% will stop bleeding, 25% will continue to bleed or rebleed in the hospital
- endoscopic hemostatic therapy is indicated for high risk groups
- Surgical intervention
- massive hemorrhage unresponsive to endoscopic control
- transfusion of more than 4 to 6 units of blood despite attempts at endoscopic control
- Long term PPI should be considered in all patients admitted to hospital with ulcer complications
Least preferable reconstrucion for patients undergoing antrectomy
Roux-en Y gastrojejunostomy
- Following antrectomy, GI continuity may be reestablsihed with
- Bilroth I gastroduodenostomy
- Bilroth II loop grastrojejunostomy
- SInce 60 to 70% gastric remnant, routine reconstruction as a roux-enY gastrojejunostomy should be avoided.
- predispose to marginal ulceration and/or gastric stasis
A 55 year old executive who is seen because of severe epigastric pain is found on esophagogastroduodenoscopy to have a large ulcer in the duodenal bulb and tests positive for H. pylori and instructed to quit smoking, but his symptoms persist and he is referred to you for further management. At this time, it would be most appropriate to recommend
NSAID cessation and urea breath test
- Indications for surgery in PUD are bleeding, perforation, obstruction, and intractability or nonhealing
- DDx of intractability
- missed cancer
- noncompliance
- Helicobacter
Which blood group is associated with an increased risk of gastric cancer
A
- Gastric cancer is more common in patients with
- pernicious anemia
- blood group A
- family history of gastric cancer
- Diets (high in nitrates, salt, fat)
- familial polyposis
- H. pylori
- Previous gastrectomy or gastrojejunostomy (>10 years)
- Tobacco use
- Menetrier disease
- Decreased risk
- Aspirn, high fresh fruit and vegetable intake, Vitamin C
A subtotal gastrectomy with D2 dissection performed for Stage 3 gastric adenocarcinoma in the antrum includes
- More than 15 lymph nodes removed
- Grossly negative margin of at least 5cm
- In the absence of involvement by direct extension, the spleen and pancreatic tail are not removed
- Billroth I gastrojejunostomy or Roux-en-Y reconstruction is used as reconstruction
The standard treatment for an isolated 3 cm gastrointestinal stromal tumor (GIST) in the body of the stomach is
Wedge resection
- GIST are submucosal tumors that are slow growing and arise from interstital cells of cajal
- Prognosis in patients with GISTs
- tumor size
- mitotic count
- metastasis ny hematogenous route
- wedge resection with Clear margins is adequate surgical treatment
- en bloc resection of involved surrounding organs is appropriate to remove all tumor
- Imatinib - blocks the activity of the tyrosine kinase product of c-kit yields excellent results
Which of the following options is the best management of a low grade gastric lymphoma of the gastric antrum
H. pylori eradication
- low grade MALT lymphoma is essentially a monoclonal proliferation of B cells, presumably arises from a background of chronic gastritis associated with H. pylori
- Low grade MALT lymphoma is not surgical lesions
Type III gastric carcinoid tumors
Sporadic lesions
-
Type I - most common type of gastric carcinoid
- occur in patients with chronic hypergastrinemia secondary to pernicious anemia or chronic atrophic gastritis
- Type II - rare, and is associated with MEN1 and ZES
- Type III - sporadic tumots, most often solitary (usually >2cm), occur more commonly in men and behave more aggresively than types I and II
- Gastric carcinoids should all be resected and small lesions (<2cm) confined to the mucosa may be treated endoscopically with endoscopic mucosal resection if there are only a few lesions (<5) and of margins are histologically negative,
- Locally invasive lesions or those >2 cm should be removed by radical gastric resection and lymphadenectomy
Watermelon stomach is best treated by
Antrectomy
- Parallel red stripes atop the mucosal folds of the distal stomach
- Predominantly affects the distal stomach
- Beta blockers and nitrates are useful in the treatment of portal hypertensive gastropathy BUT ineffective with GAVE
- Elderly women with chronic GI blood loss requirement transfusion
- most have an associated autoimmune connective tissue, and at least 25% have chronic liver disease
- Nonsurgical treatmen: estrogen and progesterone and endoscopic treatment with the neodymium yttrium aluminum garnet (Nd: YAG) laser or agon plasma coagulator
- ANtrectomy may be required to control blood loss
Treatment for severe early duming after gastrectomy that is persistent despite an antidumping diet and fiber is
Octreotide
- 100 ug SQ twice daily. this can be increased up to 500ug twice daily if necessary
- Dumping is a phenomenon consisting of a constellation of postprandial symptoms thought to be the result of the abrupt delivery of a hyperosmolar load into the small bowel due to ablation of the pylorus or decreaed gastric compliance
- early dumping occurs 15 to 30 minutes after a meal with patients becoming diaphoretic, weka, light headed and tachycardic
- Late dumping is relieved by the administration of sugar
Menetrier disease is characterized by
Hypertrophic gastric folds and hypoprotenemia
- protein losing gastropathy and hypochlorhydria
- successfully treated with the epidermal growth factor receptor blcoking monoclonal antibody cetuximab
- gastric resection may be indicated for bleeding, severe hypoproteneimia or cancer
