Stomach Flashcards
Blood supply of the stomach?
Greater curvature (L gastroepiploic via splenic artery, R gastroepiploic via GDA), lesser curvature (L gastric via celiac trunk, R gastric via common hepatic artery)
Cells in the stomach? What do they secrete? (Mucus, chief, parietal, G cells, D cells)
Mucus, chief - pepsinogen (1st enzyme of proteolysis), parietal - H+, intrinsic factor, G cells - gastrin (inhibited by H+ in duodenum, stimulated by amino acids and Ach), D cells - somatostatin (inhibits gastrin and acid release)
What stimulates acid secretion? What suppresses acid secretion?
stimulated by Ach via vagus nerve, gastrin, and histamine, suppressed by somatostatin, PGE1, secretin, CCK
Mechanism of omeprazole?
Blocks H+/K+ ATPase in parietal cell membrane (final pathway for H+ release)
Cellular pathway of acetylcholine, gastrin, histamine?
Acetylcholine and gastrin activate phospholipase (PIP -> DAG + IP3 to increase Ca+, which activates phosphorylase kinase, causing H+ release); histamine activates cAMP, activates protein kinase A which leads to H+ release
What is intrinsic factor?
Helps with absorption of vitamin b12 by binding to it, produced by parietal cells; the complex is reabsorbed in the terminal ileum
What are Brunner’s glands?
Located in the duodenum, they secrete alkaline mucus
What are dieulafoy’s ulcers?
Congenital vascular malformation typically on lesser curvature, submucosal artery that is abnormally large and tortuous, can bleed - tx w/ endoscopy, cautery, sclerosing
What is Menetrier’s disease?
Mucous cell hyperplasia, increased rugal folds, loss of parietal cells leading to achlorhydria, loss protein in stomach due to mucous hyper secretion, increased gastric Ca risk high protein diet, anticholinergic agents, Cetuximab (growth factor alpha blocker) is promising tx
Gastric volvulus: primary/secondary, axis, symptoms, treatment?
Primary (idiopathic), secondary occurs in 2/3 due to anatomical problem like paraesophageal hernia / diaphragmatic hernia, etc; usually organoaxial volvulus (long axis) antrum antero-superior, fundus postero-inferior, often assoc. w/ anatomic problem – mesenteroaxial volvulus (short axis) usually not associated with secondary anatomic defect – Tx w/ NG, endoscopic detorsion, surgery (reduction/fundoplication) vs gastric fixation via G-tube
Treatment for mallory-weiss tear
EGD with clips, tear usually on lesser curvature near GE junction
What is the most common side effect after vagotomy and what is the pathophysiology?
Diarrhea (40% of patients), caused by sustained migrating motor complexes forcing bile acids into the colon
Types of gastric ulcers?
type I = distal lesser curve (most common) - decreased/normal acid production, type II = 2 ulcers, lesser curve and duodenal - high acid production, type III = pre-pyloric ulcer - high acid production, type IV = lesser curve high/proximal/GE junction - normal/low acid production – impaired mucosal defense, V = associated with NSAIDs – “4+1 = 3+2 = 5” in order from proximal to distal
Periop chemo regimen for gastric cancer?
Based off of MAGIC trial - ECF, epirubicin, cisplatin, and fluorouracil
stomach GIST: dx, path, treatment?
most common benign gastric neoplasms, arises from mesenchymal / Cajal cells – not smooth muscle!, if malignant spreads hematogenously, usually asymptomatic, hyperechoic on ultrasound w/ smooth edges, dx w/ biopsy shows C-kit positive, +Cd117 stain – would be concerned if large (>5 cm or >5 mitoses/50 HPF), resect with 1 cm margins (microscopic positive margins do not affect survival), chemo w/ imatinib (Gleevec, tyrosine kinase inhibitor)
MALT lymphoma: underlying problem? tx?
related to h. pylori, infection induces a lymphoid infiltrate, B cell proliferation occurs; usually regresses within 1 yr after treatment for H. pylori, XRT if fails after 1 yr (CHOP - cyclophosphamide, doxorubicin, vincristine, prednisone) – 11;18 translocation are unlikely to respond w/ just H. pylori eradication
Gastric lymphoma: most common type? dx? tx?
most commonly B-cell NHL; dx w/ EGD w/ biopsy, chemo/XRT primary treatment modalities
NIH criteria for bariatric surgery
BMI >40 (or BMI >35 w/ coexisting comorbidities), failure of nonsurgical methods, psychologic stability, absence of drug/EtOH use
dumping syndrome: early vs late
occurs after gastrectomy or vagotomy/pyloroplasty, occurs from rapid entering of carbs into small bowel – early = hyperosmotic load causes fluid shifts into bowel (GI and cardiovascular symptomshypotension, diarrhea, dizziness) late = hypoglycemia from reactive increased insulin and decreased glucose – tx w/ small low fat low carb high protein meals, octreotide
Post-gastrectomy complication: bile reflux in stomach with evidence of gastritis
alkaline reflux gastritis - HIDA scan can be helpful, more likely to occur after billroth 2 vs billroth 1 - if occurs in billroth 2, surgical procedure of choice to lengthen jejunal limb, i.e. convert o roux en Y gastrojejunostomy
Post-gastrectomy complication (dx, tx): pain, steatorrhea, B12 deficiency, malabsorption
blind-loop syndrome caused by bacterial overgrowth from stasis in the afferent limb; dx w/ EGD aspirate/cx, tx w/ tetracycline and flagyl, reglan improve motility, consider shortening afferent limb
Post-gastrectomy complication (dx, tx); RUQ pain, steatorrhea, non-bilious vomiting, pain relieved w/ bilious emesis
Afferent loop syndrome caused by mechanical obstruction of afferent limb, dx w/ CT scan, potentially tx w/ balloon dilation vs shortening afferent limb
Areas of possible internal hernias after RXY gastric bypass?
1) Petersen’s defect (between Roux mesentery and transverse mesocolon), 2) mesenteric defect of the J-J / biliopancreatic limb 3) if retrocolic fashion, defect in transverse colon mesentery
Causes of bowel obstruction in post-op RXY gastric bypass?
1) internal hernia, 2) roux compression due to mesocolon scarring, 3) adhesions
Mechanism of sibutramine? Orlistat?
FDA approved medications for obesity; sibutramine blocks presynaptic uptake of serotonin, increases anorexic effect on CNS; orlistat inhibits pancreatic lipase which decreases dietary fat absorption
Most common chemo regimen for diffuse B-cell NHL of the stomach?
R-CHOP (Rituximab, Cyclophosphamide, Hydroxydaunorubicin - aka doxorubicin or adriamycin, Oncovin - vincristine, and Prednisone)
What is the first clinical manifestation of gastric leak after Roux-en-Y gastric bypass?
Tachycardia and fever
Management of perforated duodenal ulcers?
Graham patch only in most patients followed by tx of H. pylori, also if pt unstable, extensive exudative peritonitis, or long duration – if h. pylori known to be negative, than ulcer surgery should be added – highly selective vagotomy is preferred, otherwise truncal vagotomy w/ pyloroplasty
Postvagotomy syndrome: symptoms, treatment
diarrhea, gastric atony and incomplete vagotomy leading to recurrent ulcerations - not associated w/ cardiovascular manifestations; initial tx w/ dietary modifications, small frequent small meals, oral cholestyramine, loperamide, codeine, rare cases reversal of jejunal segment, octreotide is not helpful
What to do w/ patient with Zollinger-Ellison syndrome that cannot be localized with somatostatin/octreotide scintigraphy, or with Kocher maneuver?
Blind proximal duodenotomy to examine wall of duodenum (in Gastrinoma triangle - cystic duct/CBD, D2/D3, and neck/body of pancreas)
Gastric cancer staging general principles
T stage is depth (T1 invades lamina propria, T2 muscular prop or subserosa, T3 invades serosa, T4 adjacent structures), N1 is 1-6 regional nodes, N2 7-15 regional nodes, N3 more than 15 nodes; EUS best modality for assessing tumor depth and nodal disease (better for depth)
R0 vs R1 Vs R2 resection
R0 removal of all gross/microscopic, R1 removal of all macroscopic but +microscopic margins, R2 gross residual disease left behind
Risk factors for gastric Ca
dietary (smoked meats, pickled foods, nitrates), smoking, black race, H. pylori, chronic gastritis, blood type A, pernicious anemia; HNPCC, Li-Fraumeni, FAP, Peutz-Jeghers syndrome
Definition of early gastric cancer
Adenocarcinoma limited to mucosa and submucosa (regardless of LN status - T1 any N)
Best way to confirm eradication of H. pylori?
Urea breath test - serology not helpful; antral mucosal biopsy w/ histological examination is gold standard test however not practical
How do you perform a highly selective vagotomy?
Divide vagal nerves of the proximal 2/3 of the stomach where parietal cells are located and preserve distal 1/3 to maintain antral function and thus not require drainage procedure (i.e. pyloroplasty)– spares main anterior/posterior vagal trunks, divides the nerves that directly innervate proximal stomach, Crow’s feet is spared (nerves in distal 7 cm), important to divide nerve of Grassi (criminal nerve because failure to divide leads to higher ulcer recurrence rate)
most common nutrient deficiencies following gastrectomy
Iron (iron absorbed in duodenum, facilitated by acidic environment) B12 (less parietal cells means less intrinsic factor, less absorption in TI, fat malabsorption (inadequate mixing of food w/ bile and digestive enzymes), calcium (absorption facilitated by an acidic environment)
most common functional neuroendocrine tumor?
insulinoma
free air under the diaphragm, anemia, guaiac positive stool?
“kissing” duodenal ulcer = anterior duodenal ulcer w/ free peritoneal perforation, and posterior duodenal ulcer that erodes into the GDA and bleeds, manage w/ Graham patch and oversewing posterior ulcer
Phytobezoar vs trichobezoars
Phytobezoars = undigested vegetable matter, enzyme therapy (cellulase), Coke; trichobezor = hair, girls young women, most have areas of alopecia, underlying psych disorder, large trichobezar likely to require surgery (not responsive to enzyme therapy)
Greatest risk factors for rebleeding of gastric varies seen on EGD?
active spurting, > active oozing > non-bleeding visible vessel > adherent clot > flat pigment spot > clean visible ulcer base
Hyperplastic polyps: most common location, associations, types, malignancy risk, indications for surgery
Most commonly gastric polyps (70-90%), associated with chronic atrophic gastritis (usually due to H. pylori), polypoid foveolar hyperplasia / typical hyper plastic polyps; polypoid foveolar hyperplasia no malignant potential, typical hyper plastic polyp has 2% chance of malignancy (adenomatous polyps have highest risk 10-20%); fundic gastric polyps associated w/ long term PPI, low risk of cancer - treat with endoscopic polypectomy, surgical resection for sessile, large polyps, symptomatic, or w/ areas of invasive tumor
Antral vascular ectasia
watermelon stomach, leads to significantt acute/chronic GI loss
What are the components of triple therapy?
PPI and antibiotics (clarithromycin and amoxicillin, metronidazole and amoxicillin, metronidazole and tetracycline)
Most sensitive and specific test for Gastrinoma? How is it done
Secretin stimulation test - give pt bolus of secretin, check gastrin before and after, if gastrin increases 120 pg/mL or greater, highest sensitivity/specificity for Gastrinoma – octreotide scan best test for localizing the tumor
management of a type I gastric ulcer failed to heal despite maximum medical therapy?
distal antrectomy (ulcer usually near angularis incisura), reconstruction w/ gastroduodenostomy (B1) or gastrojejunostomy (B2), vagotomy unnecessary (not acid hyper secretion)
During lap Nissen, hypotension, increased end tidal co2, ventilation problems — dx/to
Tension hypercapnea- enlarge defect, red rubber to equalize pressure, needle Thoracostomy
