GI Tract Flashcards
What stimulates and inhibits gastrin production?
Stimulates -> amino acids, ACh, Ca, EtOH, antral distention, pH > 3.0
Inhibits -> pH < 3.0, somatostatin, secretin, CCK
What stimulates somatostatin secretion?
Acid in duodenum
What is the effect of somatostatin?
Inhibits gastrin, HCl, insulin, glucagon, secretin, motilin, pancreatic and biliary output
Which cells secrete CCK?
I cells in the duodenum
What stimulates and inhibits secretin?
Stimulates: fat, bile, pH < 4.0
Inhibits: pH > 4.0, gastrin
What is the effect of secretin?
Increases pancreatic HCO3 release
Inhibits gastrin release (reversed in gastrinoma)
Inhibits HCl release
What is the action of VIP?
Increased GI secretions and motility
What is the effect of glucagon on motility and sphincter of Odi?
Decreases motility
Relaxes sphincter of Odi
What is the effect of Pancreatic Polypeptide?
Decreases pancreas and biliary output
What inhibits and stimulates motilin release?
Stimulates: duodenal acid, food, vagal input
Inhibits: somatostatin, secretin, pancreatic polypeptide, duodenal fat
What is the action of motilin?
Increased intestinal motility (Phase III peristalsis)
Erythromycin acts on this receptor
What is bombesin?
Gastrin releasing peptide. Increases motility, pancreas secretion, increases acid secretion
What is Peptide YY?
Released from TI in response to fat
Decreases HCl, stomach motility, GB and pancreatic secretions
What is the criminal nerve of Grassi?
Part of the right vagus which can cause persistently high acid levels if not divided during vagotomy
Where do the anterior and posterior vagus go?
Anterior -> liver/biliary tree
Posterior -> Celiac plexus
Where does thoracic duct cross from R to L?
T4/5
What are the characteristics of the UES?
15 cm from incisors
Resting pressure 60 mmHg
Pressure with food 15 mmHg
What is the most common site of esophageal perforation?
At the cricopharynxgeus muscle (UES)
What are the characteristics of the LES?
40cm from the incisors
Normal pressure at rest 15 mmHg
Normal pressure with food 0 mmHg
What is the distance from incisors to carina?
24-26 cm
What is the treatment of Zenker’s diverticulum?
Cricopharyngeal myotomy
What is a traction diverticulum?
A true diverticulum lying laterally usually in the mid-esphagus
What is an epiphanic diverticulum?
usually associated with motility disorders
Tx: diverticulectomy, esophageal myotome on opposite side
What is the Tx of diffuse esophageal spasm?
Calcium channel blockers and nitrates
Heller myotomy if those fail (upper and lower esophagus)
What does scleroderma do to esophagus?
Loss of LES tone, dysphagia and severe reflux resulting in fibrosis
What is the phrenoesophageal membrane an extension of?
The transversals fascia
What is the key move in a fundoplication?
Identification of the left crus
What is a Collis gastroplasty?
Creation of new esophagus by stapling along the stomach cardia when not enough esophagus can be pulled into the abdomen
What are the four types of Hiatal Hernias?
I - Sliding (most common, GERD)
II - Paraesophageal (normal GE junction)
III - combined
IV - entire stomach in chest + other organ
Why does type II hiatal hernia often need repair?
High risk of incarceration
What do almost all patients with a Schatzki’s ring have?
Sliding hiatal hernia
What is treatment for a Schatzki’s ring?
Dilatation of the ring and PPI
DO NOT RESECT
What is the treatment for severe Barrett’s dysplasia?
Esophagectomy
Does a Nissen fix Barrett’s?
No, it will prevent further metaplasia but will not prevent malignancy. Need screening EGD for life
What are symptoms/signs that esophageal CA is unresectable?
Hoarseness (RLN invasion), Horner’s syndrome, Phrenic nerve, malignant pleural effusion, malignant fistula, airway invasion, vertebral body invasion
What is the blood supply for a colon interposition reconstruction?
Colon marginal vessels
What is the chemotherapy regimen for esophageal cancer?
5-FU and Cisplatin
What is the most common benign esophageal tumor?
Leiomyoma
What is the treatment of esophageal Leiomyoma?
Do NOT biopsy (scar)
>5 cm or symptoms -> enucleation via thoracotomy
What is the initial care of caustic esophageal injury?
No NG tube
Nothing to drink
Do Not induce vomiting
CT C/A -> assess for perforation
What are indications for esophagectomy in a 2nd degree caustic burn?
Sepsis, peritonitis, mediastinitis, free air, mediastinal/stomach wall air, contrast extravasation, PTx, effusion
What is the most common cause of esophageal perforation?
EGD
What is the most common site of esophageal perforation?
Cervical esophagus near cricopharynxgeus muscle
What are the initial diagnostic tests for esophageal perforation?
CXR then gastrografin swallow
What is the treatment for non-contained esophageal perforations if < 24 hours?
If no major contamination primary repair with longitudinal myotomy and muscle flap interposition
What is the treatment for non-contained esophageal perforation if > 48 hours?
Neck -> Drains only
Chest -> Resection or Exclusion + Diversion
Where is the most likely site of perforation in Boerhaave’s syndrome?
Left lateral wall 3-5 cm above GE junction
What is Hartmann’s sign?
Mediastinal crunching on auscultation -> esophageal perforation
What is Menetrier’s disease?
Mucosal cell hyperplasia, Increased rugal folds
What is the classic presentation of gastric volvulus?
Severe Pain
Nausea without vomiting
Where is the tear in Mallory Weiss usually located?
Lesser curvature near GE junction
Why does vagotomy increase liquid emptying?
Decreased receptive relaxation so increased gastric pressures
What is a truncal vagotomy?
Dividing at level of esophagus -> decreases emptying of solids
What is a proximal vagotomy?
Highly selective, divides individual fibers
Preserves “crow’s foot”,
Normal emptying of solids
What are other effects of a truncal vagotomy?
Decreased acid output, increased gastrin and G cell hyperplasia
Decreased exocrine pancreas function, bile flow, increased GB volumes
Diarrhea (40%) - > due to sustained MMCs forcing bile acids into colon
What is a Heineke-Mikulicz pyloroplasty?
Longitudinal incision and transverse closure
What is the diagnostic test for slow bleeds with difficulty localizing source?
Tagged RBC scan
What are the biggest risk factors for re-bleeding on EGD?
Spurting blood vessel (60% chance) Visible blood vessel (40%) Diffuse oozing (30%)
What is triple therapy for H. Pylori?
Amoxicillin
Flagyl/Tetracycline
Omeprazole
+/- Bismuth Salts
What are surgical indications for duodenal ulcers?
Perforation Protracted bleeding Obstruction Intractability Inability to rule out cancer If on PPI -> need acid reducing procedure as well
What are surgical options for acid reducing surgery in order of recurrence risk?
Truncal vagotomy + Antrectomy (2% mortality) Truncal vagotomy + Pyloroplasty (1% mortality) Proximal vagotomy (lowest complications, 10-15% recurrence)
What are reconstruction options after antrectomy?
Roux-en-Y GJ (best, less dumping and reflux gastritis)
B1 (GD anastomosis)
B2 (GJ anastomosis)
What is definition of major duo ulcer bleeding?
> 6 u pRBC in 24 hours, or hypotension despite transfusion
What is the surgery for bleeding duodenal ulcers?
Duodenotomy and GDA ligation
Complication: CBD injury
If on PPI -> need acid reducing surgery as well
What is the treatment for an obstructing duodenal ulcer?
PPI and serial dilations
Surgery: antrectomy and truncal vagotomy (need Bx for cancer rule out)
What is the definition of intractability for a duodenal ulcer?
> 3 months without relief while on escalating doses of PPI
Based on EGD mucosal findings, not symptoms
Where are 80% of gastric ulcers located?
Lesser curvature of the stomach
What are the types of gastric ulcers?
I - Lesser curvature low along body of stomach due to decreased mucosal protection
II - 2 ulcers (lesser curvature and duodenal) high acid
III - Pre-pyloric (high acid)
IV - lesser curvature high along cardia (decreased mucosal protection)
V - Associated with NSAIDs
Surgical indications for gastric ulcers?
Perforation, bleeding not controlled with EGD, obstruction, cannot exclude malignancy, intractability (based on EGD)
Why should you always resect gastric ulcers at the time of surgery?
High risk of malignancy
What are the two types of chronic gastritis?
Type A (funds) - Pernicious anemia, autoimmune dz Type B (astral) - Associated with H. Pylori
Where are the majority of gastric cancers located?
Antrum
What is a Krukenberg tumor?
Metastases to ovaries
What is the intestinal-type gastric CA?
Seen in high risk populations (old Japanese men)
Tx: Subtotal gastrectomy (10 cm margin)
What is the most common type of gastric cancer in the US?
Diffuse (linitis plastica)
Diffuse lymphatic invasion
Less favorable prognosis
Tx: Total gastrectomy
What is the chemotherapy for gastric cancer?
5FU, doxorubicin, mitomycin C
What is the palliative procedure for obstructing gastric CA?
Stent proximal lesions
Bypass distal lesions with G-J
What is the most common benign gastric neoplasm?
GIST
What are the characteristics of GIST?
Hypoechoic on ultrasound with smooth edges
C-KIT positive
>5 cm or > 5 mitosis/50 HPF = MALIGNANT
What is the Tx for GIST?
Resection with 1 cm margins
Imatinib if malignant
What is the most common type of lymphoma in the stomach?
non-Hodgkin’s lymphoma (B cell)
What are the treatments for gastric lymphoma?
Chemo and XRT
Surgery possible for stage I disease (confined to stomach)
What are the criteria for bariatric surgery?
BMI > 40 or > 35 with comorbidities
Failure of nonsurgical methods
Psychological stability
No drug or EtOH abuse
What gets better after weight loss surgery?
DM, cholesterol, OSA, HTN, incontinence, GERD, venous ulcers, pseudotumor cerebri, joint pain, migraines, depression, PCOS, NAFLD
What are the risks of Roux-en-Y gastric bypass?
Marginal ulcers Leak Necrosis Fe and B12 deficiency Gallstones
What is the treatment for a leak after Roux-en-Y?
early (not contained) -> re-operation
Late (likely contained) -> perc drain, abx
What is the rate of marginal ulcer development?
10%
What are symptoms of dilation of the excluded stomach after Roux-en-Y?
Hiccoughs, large stomach bubble
Tx: G-tube
Why is SBO a surgical emergency in bypass patients?
High risk of small bowel herniation, strangulation, infarction, necrosis
What are the two phases of dumping syndrome?
Hyporsomotic fluid shift (hypotension, diarrhea, dizziness)
Hypoglycemia from reactive insulin release (rare)
Tx: small, low-fat, low carb meals, no liquids with meals
Octreotide
What are surgical options for dumping syndrome?
Conversion to Roux-en-Y GJ
Operations to increase gastric reservoir (j-pouch)
Increase emptying time (reversed J loop)
What causes alkaline reflux gastritis? Tx?
Bile reflux into stomach
Tx: PPI, choleystramine, reglan
sTx: B1 or B2 to Roux-en-Y with afferent limb 60 cm distal to GJ