35 - Small Intestine Flashcards
Portion of the duodenum containing ampulla of Vater and duct of Santorini
2nd (descending)
Retroperitoneal portions of the duodenum
2nd (descending)
3rd (transverse)
Transition point of 3rd and 4th parts of duodenum
Acute angle at aorta (posterior) and SMA (anterior)
Vascular supply of duodenum
Superior (off GDA) and inferior (off SMA) pancreaticoduodenal arteries
Length of jejunum
100cm
Maximum site of all intestinal absorption
Jejunum
Length of ileum
150cm
Vascular supply of jejunum and ileaum
SMA
Enzymes of the intestinal brush border cells (4)
Maltase
Sucrase
Dextrinase
Lactase
Intestinal cells that secrete mucin
Goblet cells
Intestinal cells that secrete secretory granules and enzymes
Paneth cells
Intestinal cells that secrete 5-hydroxytryptamine (5HT)
Enterochromaffin cells
Intestinal cells that secrete alkaline solution
Brunner’s glands
Intestinal cells that represent lymphoid tissue, increased in ileum
Peyer’s patches
Antigen presenting cell in intestinal wall
M-cells
Migrating motor complex for gut motility (4 phases)
Phase 1 - rest
Phase 2 - acceleration/gallbladder contraction
Phase 3 - Peristalsis
Phase 4 - Deceleration
Hormone acting on migrating motor complex and which phase does it act on
Motilin, phase 3 (peristalsis)
Percentage of bile salts/acid reabsorbed
95%
Where is non-conjugated and conjugated bile salts reabsorbed and which is passively vs actively reabsorbed
Non-conjugated (50% passive absorption) - 45% ileum, 5% colon
Conjugated (50% active absorption w/ Na/K ATPase) - 50% terminal ileum
Symptoms of short-gut syndrome (3)
steatorrhea, nutritional deficiency (B12) and weight loss
Check for fecal fat
Sudan Red Stain
Checks for B12 absorption (in urine)
Schilling test
Amount of bowel needed to survive without TPN
75cm (50cm w/ intact ileocecal valve)
Tx for short gut syndrome (3)
Fat restriction
PPI
Lomotil
Steatorrhea is deficiency in
Fat soluble vitamins (ADEK) and essential amino acids
Non-healing fistula causes (FRIENDSS)
Foreign body Radiation Inflammatory bowel dz/Infection Epithelialization Neoplasm Distal obstruction Sepsis Steroids
MCC of small bowel obstruction without and with previous surgery respectively
Without surgery - hernia
With surgery - adhesion
MCC of large bowel obstruction without and with previous surgery respectively
Without surgery - cancer
With surgery - cancer
Signs of gallstone ileus (Rigler’s triad)
Air in biliary tree
Stone outside gallbladder on imaging
Small bowel obstruction
SBO from gallstone usually in
Terminal ileum
Gallstone ileus caused by fistula btn
gallbladder and 2nd portion of duodenum
Meckel’s diverticulum cause by
Failure of closure of omphalomesenteric duct
Types of tissues found in Meckel’s and which is most common
Pancreatic (most common) and gastric (most likely symptomatic w/ bleeding)
Most common presentation of Meckel’s in adults
Obstruction
Indication for segmental resection of Meckel’s (3)
Complicated diverticulitis (perforated)
Neck > 1/3 diameter of normal bowel lumen
Diverticulitis involving the base
Rule of 2’s of Meckel’s diverticulum (name 4-6)
2 ft from ileocecal valve 2% of population Within first 2 yrs of life w/ bleeding 2 types of mucosal tissues 2 times more common in males 2 inches long
Management of juxta-ampullary duodenal diverticula with biliary and pancreatic sxs
Biliary - Choledochojejunostomy
Pancreatic - ERCP with stent
Most common involved segment for Crohn’s
Terminal ileum
Percentage for initial presentation of Crohn’s (terminal ileum, small bowel only, colon only, perianal)
TI - 40%
SB - 20%
Colon - 35%
Perianal - 5%
Medical tx for Crohn’s (maintenance and acute flare)
Maintenance - Sulfasalazine and loperamide
Acute - Steroids
Medical tx for Crohn’s fistulas or steroid-resistant
Remicade (Infliximab)
Percentage of Crohn’s eventually needing operation
90%
Tx of abscess in Crohn’s
Percutaneous drainage
Surgical margins for Crohn’s resection
No clear margin, 2cm from gross dz
Serotonin produced by which intestinal cells
Enterochromaffin (Kulchitsky) cells
Breakdown product of serotonin, where can you measure it
5-HIAA, measured in urine
Hallmark sxs of carcinoid syndrome (2)
Flushing (kallikrein)
Diarrhea (Serotonin)
Cause of carcinoid syndrome
Bulky liver metastases
Best study for LOCALIZING carcinoid tumor not seen on CT
Octreotide scan
Highest sensitivity for DETECTING carcinoid tumor
Chromogranin A level
Most common site of carcinoid tumor
Appendix
Indication for appendectomy vs right hemicolectomy of appendix carcinoid
Appendectomy - <2cm and NOT involving base of appendix
R hemicolectomy - >/= 2cm OR involving base of appendix
Chemo regimen for unresectable carcinoid disease
5-FU and streptozocin
Tx for flushing carcinoid sx
Alpha-blockers (phenothiazine)
Can result in falsely elevated 5-HIAA levels
Fruits
Most common location of small bowel adenomas
Duodenum
Puetz-Jeghers syndrome method of inheritance
Autosomal dominant
Puetz-Jeghers syndrome most common extra intestinal malignancy
Breast Cancer
Most common MALIGNANT small bowel tumor
Adenocarcinoma
Highest proportion of small bowel adenocarcinoma
Duodenum
Pts needs a Whipple if adenocarcinoma involving this portion of duodenum
2nd (transverse)
Small bowel Leiomyosarcoma most common locations
Jejunum and ileum (most extraluminal)
Small bowel lymphoma most common location
Ileum
Cell type for small bowel lymphoma
Non-Hodgkin Lymphoma B cell type
Most common stoma infection cause
Candida
Cause of diversion colitis
Lack of short chain fatty acids (tx with SCFA enemas)
MCC of stomal stenosis
Ischemia
MCC of fistula near stoma site
Crohn’s dz
Conditions ncreased in pts with ileostomy due to loss of bile salts and HCO3
Gallstones and Uric acid kidney stones
Area most likely to perforate in appendicitis
Midpoint of the antimesenteric border
MCC of appendicitis in children
Lymphoid hyperplasia
MMC appendicitis in adults
Fecalith
Most common associations of appendicitis and pregnancy in 1st, 2nd and 3rd trimesters
1st - MMC acute abd pain
2nd - period when appendicitis most often OCCURS
3rd - period when appendicitis most often PERFORATEA
MCC of death with appendix mucocele
SBO
Sx (6) and Tx for typhoin enteritis (salmonella)
Sx - RLQ pain, diarrhea, fever, maculopapular rash, leukopenia, large mesenteric lymph nodes
Tx - Bactrim