Chapter 11, part 2 Flashcards
What is the most common true diverticulum of the GI tract?
Meckel’s diverticulum
Approximately 50% of symptomatic Meckel’s diverticulum contain ______
Ectopic gastric mucosal cells
What is the most common presenting symptom in adults of Meckel’s diverticulum?
Obstruction
Acute inflammation is also common and can mimic appendicitis
What is necessary in the pt with Meckel’s diverticulum who presents with GI bleeding? Why?
Segmental ileal resection
To eliminate the base of the diverticulum where ectopic gastric mucosa may be found and the adjacent small bowel
Rule of 2s in Meckel’s diverticulum
~2% are asymptomatic
2 types of mucosa possible (small intestine and gastric)
Located within 2 feet of the ileocecal valve
2x more common in males
Commonly presents within the first 2 yrs of life
What is the most common acquired or false diverticula of the small bowel?
Duodenal diverticula
Where are >60% of duodenal diverticula found?
In the periampullary region projecting from the medial wall
Clinical manifestations of duodenal diverticula
Obstruction
Perforation
Bleeding into the small bowel
Tx of duodenal diverticula- if pancreatic and biliary structures not involved
The most common and effective tx is diverticulectomy Kocher maneuver (dissecting the lateral peritoneal attachments of the duodenum to allow access to the pancreas, duodenum, and other retroperitoneal structures) is performed, and a duodenectomy is made
Tx of duodenal diverticula- if pancreatic and biliary structures are involved
A choledochoduodenostomy or a choledochojejunostomy to a Roux-en-Y limb may be indicated
Jejunoilial diverticula
Acquired pulsion pseudodiverticula associated with increasing age
Marker for underlying dysmotility syndrome
Most are located where blood vessels perforate the muscularis propria
Dx of jejunoilial diverticula
Enterocylsis is the study of choice
Complications of enterocylsis for jejunoilial diverticula
Diverticulitis
Obstruction
Perforation
What does jejunoilial diverticula have an associated increased risk with?
Lymphoma
What can acute mesenteric ischemia result from?
SMA embolization
SMA thrombosis
Nonocclusive mesenteric ischemia
Acute mesenteric venous thrombosis
RFs of acute mesenteric ischemia
Atrial fibrillation
CHF
Atherosclerotic coronary, carotid, or PVD
Hx of hypercoagulability
Labs for acute mesenteric ischemia
Leukocytosis Hyperkalemia Metabolic acidosis Elevated levels of: Lactate LDH ALT AST CPK
Dx of acute mesenteric ischemia
CT: Bowel dilation Wall thickening Intestinal pneumatosis Portal venous gas Mesenteric stranding
Tx of acute mesenteric ischemia
Correction of metabolic derangements and acidosis is a goal of initial therapy + cardiac monitoring + Foley catheter
Tx of acute mesenteric ischemia when SMA embolus suspected
Surgical laparotomy and embolectomy
Alternative: local infusion of thrombolytic therapy if there is no evidence of bowel infarction
Tx of acute mesenteric ischemia when SMA thrombus suspected
Bypass graft or endovascular stent is often needed to reestablish flow to the affected bowel in conjunction with thrombectomy
After the intial tx of acute mesenteric ischemia, what is indicateds?
Anticoagulation with warfarin for at least 6 mos
What may be used as an adjunct during arteriography for acute mesenteric ischemia?
Vasodilating agents, such as papverine and tolazoline
What is chronic mesenteric ischemia caused by?
Atherosclerotic dz of the celiac axis, SMA, or IMA
What are the common collateral circuits in chronic mesenteric ischemia?
The celiac artery and the gastroduodenal artery
The SMA and pancreatic branches
The SMA and IMA through the meandering mesenteric artery and the marginal artery of Drummond
The left colic and middle colic arteries
What is present only in occlusive disease?
The meandering mesenteric artery
Gold standard of dx of chronic mesenteric ischemia
Arteriography, which detects occlusion or stenosis of the celiac axis, the SMA, and the presence of collateral vessels
Tx of chronic mesenteric ischemia
Surgical reconstruction or percutaneous transluminal angioplasty with or without a stent
When is surgery used for chronic mesenteric ischemia?
Often used in younger pts with fewer comorbidities, while endovascular approaches may be preferred for the elderly and infirm
Contraindications to surgery for chronic mesenteric ischemia
Extrinsic compression of the celiac axis by the median arcuate ligament because it has a high failure rate
Frequently described techniques of surgical reconstruction for chronic mesenteric ischemia
Bypass grafting
Endarterectomy
Reimplantation
Small bowel neoplasms
The rapid transit of material through the samll bowel and low intraluminal pH may protect the mucosa from contact with carcinogens + highly evolved immune system
What is the most common type of benign neoplasm?
Adenoma
What are the three types of adenomas?
Tubular
Vilious
Brunner’s gland
Where are vilious adenomas most commonly found?
Duodenum
What is considered a large vilious adenoma?
> 5 cm
Significant malignant potential
Brunner’s gland adenoma
Found in the duodenum and are caused by hyperplastic proliferation of nl submucosal exocrine glands
No malignant potential
Resection reserved for sx
Tx for benign neoplasms
Surgical intervention is indicated bc of the possibility of CA and the risks of mechanical complications
Operation usually consists of segmental resection and primary anastomosis, though small lesions may simply be excised
What are the most common symptomatic benign tumor of the small bowel?
Leiomyomas
Where are leiomyomas most commonly located?
Jejunum
What is the most common indication for operative management of leiomyomas?
Bleeding
Where are lipomas most commonly located?
Most often intramural and located in the ileum
Hamartoma
Commonly occur as part of Peutz-Jegher’s syndrome, an autosomal dominant-inherited syndrome characterized by mucocutaneous melanotic pigmentation and GI polyps
Increased risk for the development of malignancies
Where are hemartomas usually located?
Jejunum and ileum
Presentation of hemartomas
Pts have small, 1-2 mm brown-black spots on the circumoral region of the face, buccal mucosa, palms and soles, lips, digits, and perianal area
Where are hemangiomas most commonly found?
Jejunum
Presentation of hemangiomas
Onset of bleeding may be the only presenting symptom
Diagnostic test for hemangiomas
Angiography and Tc-labeled RBC scanning
Tx for hemangiomas
If the lesion can be localized, conservative resection is recommended
If the lesion cannot be localized, intraoperative or localization via intra-operative enteroscopy may be helpful
What are the most common malignant neoplasms of the small bowel?
Adenocarcinoma
Sarcoma
Lymphoma
Carcinoid tumors
Presentation of malignant neoplasms
Weight loss
Diarrhea
Obstructive sx
Tx options for malignant neoplasms
Wilde surgical resection with regional lymph node bx
Palliative resection
Intestinal bypass to relieve sx or prevent complications
Where are adenocarcinomas more common?
Duodenum and jejunum
~50% of adenocarcinomas involve what?
Ampulla of Vater
RFs for adenocarcinomas
Adenomatous polyps
Polyposis syndromes
Crohn’s dz
FHx of hereditary nonpolyposis colorectal cancer
