Stomach

Where does the lesser curvature abruptly angle to the right and the body of the stomach ends and the antrum begins?

• Angularis incisura

Term for where the fundus forms with the left margin of the esophagus:

• Angle of His

What is the arterial blood supply to the stomach?

• 4 main arteries: left gastric and right gastric arteries along lesser curvature and left and right gastroepiploic arteries along greater curvature; blood is also supplied to the proximal stomach by the inferior phrenic arteries and short gastric arteries

Approximate percentage that an aberrant left hepatic artery originates from the left gastric artery?

• 15% to 20%

What is the largest artery to the stomach?

• Left gastric artery

In general, what is the maximal number of arteries that can be ligated, provided that the arcades along the greater and lesser curvatures are intact, that will still supply enough blood flow for the stomach to survive?

• 3 of 4 arteries can be ligated

Describe the venous drainage of the stomach:

• Left gastric (coronary) and right gastric veins usually drain into the portal vein; left gastroepiploic vein drains into the splenic vein; right gastroepiploic vein drains into the superior mesenteric vein

What happens to the left vagus and right vagus at the gastroesophageal (GE) junction?

• Left vagus becomes anterior and the right vagus becomes posterior (LARP mnemonic)

Where does the stomach receive its extrinsic parasympathetic and sympathetic innervation?

• Parasympathetic via the vagus and sympathetic via the celiac plexus

Where does the sympathetic nerve supply to the stomach originate from?

• From T5 to T10 (travels in splanchnic nerve to celiac ganglion)

Which vagus gives off a hepatic branch to the liver and continues along the lesser curvature as the anterior nerve of Latarjet?

• The left vagus

Which nerve gives off a branch to the celiac plexus and continues posteriorly along the lesser curvature?

• The right vagus

Which nerve is the first branch of the right or posterior vagus nerve and can lead to recurrent ulcers if left undivided?

• The criminal nerve of Grassi

Where along the vagus is a truncal vagotomy performed?

• Above the celiac and hepatic branches of the vagi

Where along the vagus nerve is a selective truncal vagotomy performed?

• Below the celiac and hepatic branches of the vagi

Where along the vagus nerve is a highly selective vagotomy performed?

• At the crow's feet to the proximal stomach while preserving the portion innervating the antrum and pylorus

The intrinsic or enteric nervous system of the stomach consists of which autonomic plexuses?

• Auerbach and Meissner autonomic plexuses

What layer of the stomach lies between the mucosa and the muscularis propria that is the strongest layer of the gastric wall?

• Submucosa

How many layers of smooth muscle make up the muscularis propria (muscularis externa) of the stomach?

• 3 layers of smooth muscle

Which layer of the muscularis propria (muscularis externa) is the only complete muscle layer of the stomach wall, is circular, and becomes progressively thicker and functions as a true anatomic sphincter at the pylorus?

• The middle layer of smooth muscle

Gastric mucosa consists of what kind of epithelium?

• Columnar glandular epithelium

Where are parietal cells in the stomach mainly found? What do parietal cells secrete?

• Body; secretion of intrinsic factor and acid

Where in the stomach will there be a complete absence of parietal cells?

• The cardia and prepyloric antrum

Where are chief cells in the stomach mainly found? What do chief cells secrete?

• Body; pepsinogen (converted to pepsin by gastric acid)

Where are G cells in the stomach mainly found? What do G cells secrete?

• Antrum; gastrin

Where are D cells in the stomach mainly found? What do D cells secrete?

• Body and antrum; somatostatin

Where are gastric mucosal interneurons mainly found? What peptide is released by gastric mucosal interneurons?

• Body and antrum; gastrin-releasing peptide

Where are endocrine cells in the stomach mainly found? What hormone do endocrine cells in the stomach release?

• Body; ghrelin

Process by which the proximal portion of the stomach relaxes in anticipation of food intake:

• Receptive relaxation and gastric accommodation

Name ulcerogenic (excess acid secretion) causes of hypergastrinemia:

• Antral G-cell hyperplasia or hyperfunction, gastric outlet obstruction, retained excluded antrum, short-gut syndrome, Zolinger-Ellison syndrome

Name nonulcerogenic (normal or low acid secretion) causes of hypergastrinemia:

• Acid-reducing procedure (vagotomy), antisecretory agents (proton pump inhibitors [PPIs]), atrophic gastritis, chronic renal failure, Helicobacter pylori infection, pernicious anemia

What are the 3 local stimuli that regulate gastric acid secretion by the parietal cell?

• Acetylcholine, gastrin, and histamine

The basal level of acid secretion accounts for roughly what percentage of maximal acid output?

• ~10%

What is the approximate rate of hydrochloric acid production during basal acid secretion?

• 1 to 5 mmol/h

What are the 3 phases of acid secretory response to a meal?

• Cephalic, gastric, and intestinal

Histamine utilizes which second messenger to stimulate acid secretion by parietal cells?

• Intracellular cyclic AMP

Acetylcholine and gastrin utilize which second messenger to stimulate acid secretion by parietal cells?

• Calcium (phospholipase C converts membrane-bound phospholipids into inositol triphosphate (IP3), which mobilizes calcium from intracellular stores)

Mechanism by which PPIs inhibit acid secretion?

• A covalent disulfate bond forms between the drug and the cysteine residues on the subunit of the H/K-ATPase leading to irreversible inhibition of the proton pump

Why do PPIs have a longer duration of action than their plasma half-life?

• The drug is covalently bonded to the H/K-ATPase leading to irreversible inhibition, so new proton pumps need to be synthesized before the recovery of acid secretion occurs

What converts pepsinogen into pepsin?

• Gastric acid

How is the maximal acid output (MAO) determined after gastric analysis?

• By averaging the output of the last two 15-minute periods after secretogogue administration

What is the usual range for MAO?

• 10 to 15 mEq/h

How is the peak acid output obtained after gastric analysis?

• It is the highest rate of secretion obtained during a 15-minute period following secretogogue administration

Gastric motility begins with the depolarization of which cells?

• Gastric pacemaker cells of Cajal located in the midbody of the stomach along the greater curvature

How many phases are in the myoelectric migrating complex (MMC)?

• 4 phases

How long does each cycle of the MMC last?

• 90 to 120 minutes

What happens in phase I of the MMC?

• Also known as the quiescent phase; slow waves are present without action potentials; increase in gastric tone but no gastric contraction

What happens in phase II of the MMC?

• Motor spikes are associated with slow waves and occasional gastric contractions; gallbladder contraction

What happens in phase III of the MMC?

• Motor spike activity is associated with each slow wave; forceful gastric contractions happen every 15 to 20 seconds; the stomach is cleared of large indigestible food substances

What happens in phase IV of the MMC?

• A brief recovery period before the next MMC cycle

List protective factors to gastric barrier function:

• Blood flow, bicarbonate secretion, cell renewal, endogenous prostaglandins, growth factors, mucus production

List damaging factors to gastric barrier function:

• Duodenal reflux of bile, ethanol ingestion, H pylori, hydrochloric acid secretion, hypoxia, ischemia, nonsteroidal anti-inflammatory drugs (NSAIDs), pepsins, smoking

Approximate percentage of gastric ulcers associated with H pylori:

• 75%

Approximate percentage of duodenal ulcers associated with H pylori:

• 90%

Most common cause of peptic ulcer disease:

• H pylori infection

What is the second most common cause of peptic ulcer disease?

• NSAID ingestion

Where do gastric ulcers usually occur?

• On the lesser curve near the incisura (~60%; type I)

What is a type I gastric ulcer?

• Gastric ulcer occurring on the lesser curvature near the incisura

What is a type II gastric ulcer?

• Gastric ulcer located in the body of the stomach in combination with a duodenal ulcer

What is a type III gastric ulcer?

• Prepyloric gastric ulcer

What is a type IV gastric ulcer?

• Gastric ulcer that occurs high on the lesser curve near the GE junction

What is a type V gastric ulcer?

• Drug-induced (NSAIDs) gastric ulcer that may occur anywhere in the stomach

Which types of gastric ulcer are not associated with excess acid secretion?

• Type I and IV

Which types of gastric ulcer are associated with excess acid secretion?

• Type II and III

Name the ulcer: multiple, superficial erosions that begin in the proximal stomach and progress distally in a patient with central nervous system disease:

• Cushing ulcer

Name the ulcer: multiple, superficial erosions that begin in the proximal stomach and progress distally in a patient with >30% body surface area burn:

• Curling ulcer

Where in the stomach is stress gastritis usually seen?

• Fundus

Initial management for a patient with stress gastritis with UGI bleeding:

• A,B,Cs; fluid resuscitation with correction of any platelet/coagulation abnormalities; blood transfusion if needed; administration of broad-spectrum IV antibiotics in patients with sepsis, saline lavage of the stomach through a nasogastric (NG) tube; administration of antisecretory agents after the NGT aspirate runs clear

Dose of vasopressin for the control of acute GI bleeding?:

• 0.2 to 0.4 IU/min as a continuous infusion for a maximum of 48 to 72 hours

Indications for operation with stress gastritis:

• Recurrent or persistent bleeding requiring >6 units of blood (3,000 mL)

After taking the patient to the operating room, how would you control the bleeding associated with stress gastritis in a hemodynamically stable patient?

• Make a long anterior gastrotomy along the proximal stomach/fundus; clear the gastric lumen of blood; inspect the mucosal surface for bleeding points; oversew all bleeding areas with figure-of-eight stitches taken deep within the gastric wall; close the anterior gastrotomy; perform a truncal vagotomy and pyloroplasty (less commonly a partial gastrectomy with vagotomy can be performed)

After taking a patient with life-threatening hemorrhage refractory to other forms of therapy to the OR, what procedure would you perform to control the bleeding?

• Gastric devascularization procedure (faster) versus total gastrectomy

Term for a disruption of the gastric mucosa (high on lesser curve at GE junction) that results from forceful vomiting, retching, coughing, or straining:

• Mallory-Weiss tear

What percentage of acute UGI bleeds are accounted for by Mallory-Weiss tears?

• 15%

What is the overall mortality rate from a Mallory-Weiss tear?

• 3% to 4%

Treatment for active bleeding from a Mallory-Weiss tear that continues after initial resuscitation?

• Esophagogastroduodenoscopy (EGD) (band ligation, epinephrine injection, hemoclipping, multipolar electric coagulation) versus angiographic intra-arterial infusion of vasopressin or transcatheter embolization (in patients with severe comorbidities)

Indications for surgery in a patient with an acute bleed from a Mallory-Weiss tear?

• >6 U packed red blood cells (PRBC) transfused; failure of EGD to stop bleeding; failure of angiographic embolization (in patients with severe comorbidities)

If surgery for active bleeding from a Mallory-Weiss tear is indicated, what procedure would you perform?

• Anterior gastrotomy and oversewing of the bleeding site with deep 2-0 silk ligatures with reapproximation of the gastric mucosa

If surgery for active bleeding from a Mallory-Weiss tear in the distal esophagus is indicated, how might your operative approach change?

• Rather than laparotomy and anterior gastrotomy, you may need a left thoracotomy and esophagotomy followed by suture ligation

What disease process is characterized by erosion of the superficial mucosa overlying an abnormally large (1–3 mm) tortuous resulting in bleeding?

• Dieulafoy lesion

Are Dieulafoy lesions more common in men or in women?

• Men (M:F = 2:1)

Peak incidence for Dieulafoy lesion:

• 5th decade

Diagnostic modality of choice for Dieulafoy lesion:

• EGD

Where do Dieulafoy lesions usually occur in the stomach?

• 6 to 10 cm from the GE junction generally in the fundus near the cardia

What is the classic presentation of a patient with a Dieulafoy lesion?

• Sudden onset of massive, painless, recurrent hematemesis with hypotension

After resuscitation, what initial attempts should be made to stop acute bleeding from a Dieulafoy lesion?

• Endoscopic modalities (band ligation, heater probe, hemoclipping, injection sclerotherapy, multipolar electrocoagulation, noncontact laser photocoagulation) or angiography if endoscopy cannot identify the bleeding source

Surgical management of a patient with Dieulafoy lesion:

• Gastric wedge resection to include the offending vessel (laparotomy with gastrotomy vs laparoscopically with intra-op endoscopy)

What are the 2 ways that gastric varices can develop?

• In conjunction with esophageal varices in the setting of portal hypertension (HTN); sinistral HTN from splenic vein thrombosis

Treatment for gastric varices in the setting of splenic vein thrombosis:

• Splenectomy

Treatment for gastric varices in the setting of portal HTN:

• Volume resuscitation and correction of any coagulopathy; temporary tamponade with Sengstaken-Blakemore tube; endoscopic banding or sclerotherapy; transjugular intrahepatic portosystemic shunt (with possible balloon-occluded retrograde transvenous obliteration of a gastrorenal shunt with ethanolamine oleate)

What study should be performed in patients with bleeding gastric varices prior to surgical intervention?

• Abdominal ultrasound to document splenic vein thrombosis (portal HTN often accompanies gastric varices)

Term for when a gastric volvulus occurs along the stomach's longitudinal axis:

• Organoaxial

Term for when a gastric volvulus occurs along the stomach's vertical axis:

• Mesenteroaxial

Which type of gastric volvulus is more common: organoaxial or mesenteroaxial?

• Organoaxial (two thirds of cases)

What is Borchardt triad?

• Sudden onset of constant, severe upper abdominal pain; recurrent retching with inability to vomit; inability to pass an NG tube

Which type of gastric volvulus more often occurs acutely and is associated with a diaphragmatic defect?

• Organoaxial gastric volvulus (mesenteroaxial volvulus usually recurrent and not associated with a diaphragmatic defect)

What might you see on plain film of the abdomen in a patient with gastric volvulus?

• A gas-filled viscus in the chest or upper abdomen

Surgical treatment for a spontaneous gastric volvulus without an associated diaphragmatic defect:

• Detorsion and fixation of the stomach by gastropexy or tube gastrostomy through a transabdominal approach

Surgical treatment for a gastric volvulus with an associated diaphragmatic defect:

• Reduction and uncoiling of the stomach through a transabdominal approach; repair of the diaphragmatic defect; resection of compromised stomach if necessary; consideration to perform fundoplication; fixation of stomach with gastropexy versus tube gastrostomy

Term for a collection of nondigestible vegetable matter formed from within the GI tract:

• Phytobezoar

Term for a collection of hair formed from within the GI tract?

• Trichobezoar

What types of patients usually get phytobezoars?

• Patients with impaired gastric emptying after gastric surgery; diabetics with autonomic neuropathy

What enzyme can be administered to attempt dissolution of a bezoar?

• Papain

How is papain administered?

• 1 teaspoon of Papain (found in Adolph Meat Tenderizer) in 150 to 300 mL of water is given several times daily

Treatment for a phytobezoar?

• Enzymatic débridement followed by endoscopic fragmentation versus aggressive Ewald tube lavage; surgical removal if these methods fail

Describe the typical patient who presents with a trichobezoar:

• Long-haired females who often deny eating their own hair

Treatment for a trichobezoar:

• Surgical removal; may attempt enzymatic therapy, endoscopic fragmentation, or vigorous lavage for small trichobezoars; psychiatric evaluation (recurrent bezoar formation common)

In what percentage of hyperplastic polyps in the stomach can adenocarcinoma be found?

• 2%

Treatment for a patient with a hyperplastic polyp in the stomach:

• Endoscopic polypectomy for histologic examination

In what percentage of adenomatous polyps in the stomach can adenocarcinoma be found?

• 20%

Treatment for a patient with an adenomatous gastric polyp:

• Endoscopic polypectomy as long as the entire polyp can be removed and no invasive cancer is in the specimen with close follow-up with serial endoscopies because of the increased risk for coincident gastric carcinoma

Name nutritional factors associated with an increased risk of developing gastric cancer:

• Salted meat or fish, high complex-carbohydrate consumption, high nitrate consumption, low fat or protein consumption

Name medical factors associated with an increased risk of developing gastric cancer:

• Adenomatous polyps, gastric atrophy and gastritis, H pylori infection, male gender, prior gastric surgery

Name environmental factors associated with an increased risk of developing gastric cancer:

• Lack of refrigeration, low socioeconomic status, poor drinking water (well water), poor food preparation (salted, smoked), smoking

What percentage of all malignant gastric neoplasms are adenocarcinomas?

• 95%

Term for a diffusely infiltrating gastric carcinoma that involves the entire stomach:

• Linitis plastica

According to the 6th edition of the AJCC Cancer Staging Manual, what is a T1 gastric cancer?

• Tumor invades lamina propria or submucosa

According to the 6th edition of the AJCC Cancer Staging Manual, what is a T2 gastric cancer?

• Tumor invades muscularis propria or subserosa

According to the 6th edition of the AJCC Cancer Staging Manual, what is a T2a gastric cancer?

• Tumor invades muscularis propria

According to the 6th edition of the AJCC Cancer Staging Manual, what is a T2b gastric cancer?

• Tumor invades subserosa

According to the 6th edition of the AJCC Cancer Staging Manual, what is a T3 gastric cancer?

• Tumor penetrates serosa (visceral peritoneum) without invasion of adjacent structures

According to the 6th edition of the AJCC Cancer Staging Manual, what is a T4 gastric cancer?

• Tumor invades adjacent structures

According to the 6th edition of the AJCC Cancer Staging Manual for gastric cancer, what is N1 nodal status?

• Metastasis in 1 to 6 regional lymph nodes

According to the 6th edition of the AJCC Cancer Staging Manual for gastric cancer, what is N2 nodal status?

• Metastasis in 7 to 15 regional lymph nodes

According to the 6th edition of the AJCC Cancer Staging Manual for gastric cancer, what is N3 nodal status?

• Metastasis in more than 15 regional lymph nodes

What is the minimum number of nodes that must be evaluated for accurate staging of gastric carcinoma?

• 15 nodes

In regards to gastric cancer, what is an R0 resection?

• Microscopically margin-negative resection with no gross or microscopic tumor remaining in the tumor bed

In regards to gastric cancer, what is an R1 resection?

• Removal of all macroscopic disease with positive microscopic margins for tumor

In regards to gastric cancer, what is an R2 resection?

• Gross residual disease

In regards to gastric cancer, what is a D1 resection?

• Removal of group 1 lymph nodes (right paracardial, left paracardial, lesser curvature, short gastric, right gastroepiploic, left gastroepiploic, suprapyloric, infrapyloric)

In regards to gastric cancer, what is a D2 resection?

• Removal of group 1 and 2 lymph nodes (right paracardial, left paracardial, lesser curvature, short gastric, right gastroepiploic, left gastroepiploic, suprapyloric, infrapyloric + left gastric, anterior common hepatic, celiac artery, splenic hilum, proximal splenic, distal splenic, left hepatoduodenal, superior mesenteric vein)

In regards to gastric cancer, what is a D3 resection?

• D2 resection with removal of paraaortic nodes

Diagnostic modality of choice for gastric cancer:

• Flexible upper endoscopy

Desired margin of resection for gastric cancer:

• 5 to 6 cm

What procedure needs to be performed to completely remove station 10 nodes during a Japanese-style D2 resection?

• Splenectomy (station 10 nodes are parasplenic)

What procedure needs to be performed to completely remove station 11 nodes during a Japanese-style D2 resection?

• Partial pancreatectomy (station 11 nodes are parapancreatic)

Which patients should receive adjuvant chemoradiation following complete surgical resection for gastric cancer?

• Patients with T3/T4 lesion, node-positive cancers, or microscopically positive resection margins

Usual time period for the recurrence of gastric cancer after gastrectomy for gastric cancer:

• Within the first 3 years after gastrectomy

What are the most common sites of locoregional recurrence after gastrectomy for gastric cancer?

• Gastric remnant at the anastomosis, gastric bed, regional nodes

Areas where gastric cancer hematogenously spreads:

• Liver, lung, bone

How should patients treated with gastrectomy for gastric cancer be followed?

• Complete history and physical examination every 3 to 4 months for 1 year

• Every 6 months for 2 years

• Yearly thereafter

• Labs (CBC and LFTs) obtained as clinically indicated

• CXR/CT A/P where indicated

• If a subtotal gastrectomy was performed yearly endoscopy may be necessary.

Most common site of lymphoma in the GI tract:

• Stomach

Most common gastric lymphoma:

• Diffused large B-cell lymphoma (55%)

Second most common gastric lymphoma:

• Extranodal marginal cell lymphoma (mucosa-associated lymphoid tissue [MALT])

Treatment for gastric lymphoma:

• Chemoradiation (cyclophosphamide, hydroxydaunorubicin, oncovin, prednisone [CHOP] regimen usually employed) versus multimodal therapy (resection for gastric lymphoma controversial)

Treatment for early-stage gastric MALT lymphoma:

• H pylori eradication alone with repeat endoscopy in 2 months to document clearance of infection and biannual endoscopy for 3 years to document regression

What characteristics of MALT lymphoma predict failure after H pylori eradication alone?

• Nodal involvement, nuclear Bcl-10 expression, transformation into a large cell phenotype t(11;18), transmural tumor extension

Most common mesenchymal tumor of the GI tract?

• GIST

What mutation is associated with GISTs?

• c-kit

What is the goal of surgery when treating GISTs?

• A margin-negative resection with en bloc resection of adjacent organs if involved by direct extension

What competitive tyrosine kinase inhibitor can be given to patients with unresectable and metastatic GISTs and as adjuvant therapy in clinical trials?

• Imatinib mesylate (Gleevec)

What disease is otherwise known as a hypoproteinemic hypertrophic gastropathy and is characterized by gastric mucosa with a cobblestone/cerebriform appearance from massive gastric folds in the fundus and corpus of the stomach?

• Ménétrier disease

What will be seen on histological examination with Ménétrier disease?

• Expansion of surface mucous cells (foveolar hyperplasia); absent parietal cells

What is the treatment for a patient with Ménétrier disease who develops dysplasia/carcinoma or continues to have massive protein loss despite optimal medical therapy?

• Total gastrectomy