Small Bowel Flashcards
What is the most common causes of small bowel obstruction the US?
1) adhesions from prior surgery
2) hernia
3) neoplasm
What percent of patients who present with SBO will require a surgery during the index admission?
approx 25%
What is the difference between open loop and closed loop bowel obstructions?
open loop obstructions are able to be decompressed via an NG tube; closed loop obstructions are closed at both the proximal and the distal ends
What is the electrolyte profile abnormality seen in any patient who has been vomiting for a significant time?
hypokalemic, hypochloremic metabolic alkalosis with a paradoxical aciduria
What are the indications for immediate surgery in a patient with a SBO?
- peritonitis
- evidence of bowel perforation
- Closed loop obstructions
- bowel strangulation
What percent of patients with Crohn’s Disease will ultimate require an operation?
70%
What are the macroscopic findings in Crohn’s Disease?
- fat wrapping
- aphthous ulcers
- transmural inflammation
What are the 3 general “types” or categories of Crohn’s Disease?
- fibrostenotic
- inflammatory
- penetrating
What are the effects of smoking on Crohn’s Disease?
- higher incidence of fibrostenotic and penetrating types
- worse perianal disease
- high rates of surgery
- high rates of post-surgical recurrence
What is the top down approach to Crohn’s Disease medications?
1) 5-ASA or sulfasalazine
2) Systemic steroids
3) Immunomodulators (azathiprine, 6-mercaptopurine, or methotrexate)
4) Biologics (Infliximab, adalimumab, cetrolizumab)
If a patient is on 5-ASA or sulfasalazine, when should these medications be stopped and started in regards to surgery?
they can be taken up to the day of surgery and restarted immediately after
What are the currently available biologics used in the treatment of Crohn’s Disease? How do they work?
- infliximab (Remicade), Adalimumab (Humira), and certolizumab pegol ( Cimzia)
- all inhibit TNF mediated inflammation
What is the most common indication for surgery for Crohn’s Disease?
medically refractory disease
What cancers are patients with Crohn’s Disease at increased risk for?
- primary small bowel adenocarcinoma
- Colorectal cancer
What should always be performed in a patient with Crohn’s Disease that is undergoing a stricturoplasty?
a biopsy of the stricture because many times malignancy of the small bowel in the setting of Crohn’s Disease does not present with a mass
What are the advantages of stricturoplasty compared to resection in Crohn’s Disease? Disadvantages?
- Advantages: decreased recurrence rate, preserved bowel length, and possible restoration of function
- Disadvantages: longer operative time, slightly increased risk of post-operative bleeding
How would you surgically treat a symptomatic enteroenteric fistula in a Crohn’s Disease patient?
resection of the diseased segment of bowel with transverse closure of the innocent bystander segment of bowel. If the bystander segment does not appear to be healthy (inflammed, edematous, etc) or situated on the mesenteric side then resection should occur
How would you surgically treat an enterovesicular fistual in Crohn’s Disease?
resection and primary anastomosis of the diseased bowel and oversew the bladder with an absorbable suture (vicryl) to avoid future stone formation
How would you surgically treat an enterovaginal or intrauterine fistula in Crohn’s Disease?
resection of the disease bowel with primary anastomosis. The uterus or vagina will often heal spontaneously after resection of the diseased bowel
What are the absolute contraindications to stricturoplasty in Crohn’s Disease?
- perforation
- Neoplasia
- fistula
- severe malnutrition
What are the relative contraindications to stricturoplasty in Crohn’s Disease?
- Abscess
- Long, severely narrowed segments of bowel
What percent of patients with Crohn’s Disease who undergo a first operation will require a second operation?
approx 50%
What is the treatment of choice for symptomatic nonphlegmonous jejune-ileal Crohn’s Disease fibrotic strictures?
strictureplasty
When is strictureplasty contraindicated in Crohn’s Disease?
- impaired nutritional status
- Dyplasia or cancer at the stricture site
- Localregional sepsis (abscess, phlegmon, peritonitis)
When should azathioprine be stopped when preparing a Crohn’s Disease patient for the OR?
- it shouldn’t be stopped. Azathioprine has no impact on post-operative morbidity and should be maintained through surgery
What is the main determinants in choosing between types of strictureplasty?
- length of stricture and number of strictures
Briefly describe the Heineke-Mikulicz strictureplasty? What length of stricture is ideal for this type of repair?
- a longitudinal incision is made on the anti mesenteric side of the bowel extending 2 cm proximal and distal to the stricture. The enterotomy is then close in a transverse fashion.
- strictures
How does the Judd strictureplasty differ from the Heineke-Mikulicz strictureplasty?
The Judd strictureplasty is used when a fistula is present in the proposed site of the enterotomy. The enterotomy incorporates the fistula and then the bowel is closed the same as the Heineke-Mikulicz technique.
What technique can be used if the bowel proximal to a stricture is dilated?
The Moskel-Walske-Neumayer technique. Similar to the Heineke-Mikulicz technique, but the enterotomy is made with a Y shaped incision where the fork of the Y is pointing at the dilated end
Brief describe the Finney strictureplasty? What length stricture is ideal for this type of repair?
- The strictured bowel is folded over itself to form a loop at its midsection. A longitudinal enterotomy is performed halfway between the mesenteric and antimesentric borders. The opposing edges of the bowel are then sutured together in a side to side anisoperistaltic enteroenterostomy.
- 7 cm to 15 cm
Briefly describe the Michelassi strictureplasty? What length stricture is ideal for this type of repair?
- The mesentery of the small bowel loop to undergo strictureplasty is divided at its midpoint. The proximal end of the loop is moved over the distal end in a side to side fashion. The two loops are approximated with Lembert sutures. Longitudinal enterotomies are made on both loops. The edges are the sutured together in a running fashion on the back wall and a Connell stitch on the front. Another layer of Lembert sutures are then placed on the anterior side.
- > 15 cm
What is the most common primary malignancy of the small bowel?
Neuroendocrine tumors
Where is the most common location in the small bowel for neuroendocrine (carcinoids) tumors to occur?
ileum
What is carcinoid syndrome? What percentage of small bowel carcinoids cause this?
- Flushing (of the upper torso and face) and diarrhea due to secretion of metabolically undegraded vasoactive amino (specifically serotonin) in to the systemic circulation
- Approximately 35%
What are the two biochemical tests used to diagnose carcinoid tumors?
- hydroxyindolacetic acid (5-HIAA)
- chromogranin A
What can cause false positive plasma levels of chromogranin-A?
PPIs
What is the treatment for small bowel neuroendocrine tumors (carcinoids)?
en bloc resection with extensive lymphadenectomy and wide resection of the mesentery
- lymphadenectomy and resection of the mesentery because metastatic spread to the regional lymph nodes is common
What is a carcinoid crisis? How is it treated?
- excessive cutaneous flushing, hyperthermia, shock, arrhythmias, and bronchial obstruction
- octreotide given routinely in the pre-operative period. Once it sets in you manage the symptoms
T/F: Small bowel GISTs tend to be more aggressive than gastric GISTs?
- true
What determines a low risk small bowel GIST?
What determines a moderate risk small bowel GIST?
5-10 cm and
What determines a high risk small bowel GIST?
> 5 cm and > 5 mitoses/50 HPF
What is the medical therapy available for treatment of GIST? How does it work?
- Imatinib
- Inhibits KIT, a tyrosine kinase receptor
What are the guideline for giving imatinib to patient with a GIST pre-operatively? Post-operatively?
- any patient who has borderline resectable disease or if decreasing tumor size will make surgery less extensive or easier
- any patient with positive margins or residual disease, and any patient with a tumor > 3cm and negative margin
Where is the most common site of extra nodal lymphoma?
GI tract, specifically the ileum due to the high concentration of lymphoid tissue in the ileum
What bacteria is associated with mucosal-associated lymphoid tissue (MALT) type lymphoma?
H pylori
What is the most common type of malignancy of the small bowel?
metastases
What are the 3 common types of small bowel diverticula?
- duodenal
- Jejuno-ileal
- Meckel’s
Which types of small bowel diverticula are true diverticula? Which type are false diverticula?
- Meckel’s diverticula is a true diverticula
- duodenal and jejuno-ileal diverticula are typically false
What is the cause of a Meckel’s diverticula?
incomplete closure of the omphalomesenteric or vitelline duct during gestation
Where is the most common location for a duodenal diverticula?
2/3 are located in the periampullary region, mostly on the medial wall
What is the treatment for an asymptomatic duodenal diverticula?
nothing. Do not treat asymptomatic diverticula.
What is the first line treatment for symptomatic duodenal diverticula?
non-operative management with bowel rest, antibiotics, endoscopic or IR treatments
What are the indication(s) to operate on a symptomatic duodenal diverticula?
- emergent operation for bleeding or perforation
- failure of non-operative treatments
What is the first line treatment of symptomatic jejuno-ileal diverticula?
- medical with bowel rest, antibiotics, pain control
What are the indication(s) for operative intervention in jejune-ileal diveriticula?
- failure of medical management during symptomatic phase
- perforation in an unstable patient
When operative management is indicated for jejuno-ileal diverticula
removal of the offending part of the small bowel. Do not attempt to remove all diverticula
What is the most common congenital anomaly of the alimentary tract?
Meckel’s diverticulum
What are the Meckel’s diverticulum rule of 2’s?
- found within 2 feet of the ileocecal valve
- 2% of the population
- 2 possible heterotopic tissues (gastric and pancreatic)
- 2 x more common in males
- 2% become symptomatic
- Usually discovered within the first 2 years of life
What is the diagnostic test(s) if a Meckel’s diverticulum is suspected?
- contrast enhanced CT
- technitium 99m pertechnetate scan which will concentrate in the etopic gastric tissue
What is the treatment for a symptomatic Meckel’s diverticulum?
surgical excision; removal of the entire piece of small bowel not just the diverticulum
A symptomatic Meckel’s diverticulum is virtually indistinguishable from what other common cause of acute abdominal pain?
acute appendicitis; in fact if a patient is taken to the OR for acute appendicitis and it is not found, one should run the terminal ileum looking for a Meckel’s diverticulum
What is the management strategy for a Meckel’s diverticulum found incidentally?
- in children remove it
- in adults leave it
How common is Roux stasis syndrome after Roux-en Y gastrojejunostomy? What is typically the cause?
- 25-30%
- a Roux limb > 40 cm
How is Roux stasis syndrome diagnosed?
clinically. It presents like gastroparesis in a patient after a Roux-en Y gastrojejunostomy
What are the treatment options for Roux stasis syndrome?
- Prokinetics, antiemetics, limiting narcotics
- Total gastrectomy in patients who do not improve with non-surgical methods
How common is post-vagotomy diarrhea after a vagotomy?
- 20%
How does post-vagotomy diarrhea present?
- diarrhea 30-60 minutes after a meal
- diarrhea can occur anytime and often patients have up to 20 watery stools per day, most not related to a meal
What is the treatment of post-vagotomy diarrhea?
- dietary modifications with more fiber
- bulking agents
- loperamide or codeine
What is the cutoff for post-operative ileus vs. prolonged post operative ileus?
post operative ileus lasts up to 5 days. When it lasts more than 5 days it is a prolonged post operative ileus
