Small Bowel Flashcards
Nutrient vs. Water absorption small vs. large bowel
Small bowel: Nutrient and water
Large: Water
The 4 portions of the duodenum
Bulb – 90% ulcers
Descending – ampulla/dcuts
Transverse – 3
Ascending – 4
Which portions of the duodenum are the acute angle between the aorta and SMA
3 and 4
Vascular supply of duodenum
GDA (Superior (A/P superior))/Pancreaticoduodenal (IMA)
Jejunum – T/F Maximum site of all absorption
100 cm long; long vasa recta, circular muscle folds. True
B12 is absorbed in…
TI
Bile acids are absorbed in …
Ileum, TI (conjugated)
Fe is absorbed in the …
Duodenum
Folate is absorbed in the …
TI
Does the ileum have long or short vasa recta
Short
95% of NaCl and 90% of water absorbed in the jujunum or ileum
Jejunum
Which is longer the jejunum or ileum
Ileum (150 vs 100 cm)
Name the different cell types in the small intestine
Absorptive Goblet: mucin Paneth: secretory granules Enterochromaffin (carcinoid) Brunners; Peyers; M cells
Most important hormone in the migrating motor complex (which phase of gut motility?)
Motilin -- I - rest II - acceleration and GB contraction III - peristalsis IV - decel
95% of bile salts are re-absorbed
50% active resorption in TI (Na/K ATPase)
Why do gallstones form after TI resection
Malabsorption of bile salts
How is short gut diagnosed?
Symptoms, not length of bowel
Symptoms of short gut
Weight loss, steatorrhea, nutritional deficinency
How do you check for fecal fat?
Sudan red stain
What test do you use for B12 absorption
Schilling test
How much bowel do you need to survive off TPN / vs. with a competent ileocecal valve?
75cm to survive off TPN, 50cm with competent ileoceal valve
Treatment of short gut
Restrict fat, PPI, Lomotil
Causes of statorrhea
Gastric hypersecretion of acid, increased intestinal motility; interrpution of bile sale resorption (TI resection); decreased panc enzymes; weight loss / ADEK essential fatty acids
Causes of non-healing fistula
FRIENDS
Foreign body, radiation, IBD, epithelialization, neoplasm, distal obstruction, sepsis/infection
High output fistulas
More likely with proximal bowel (duodenum, proximal jejunum); less likely to close with conservative management
Which fistulas are more likely to close: colon or small bowel
Colon
Patients with a fistula and persistent fever
Abscess: fistulogram, CT, UGI with SBFT
Most fistulas are iatrogenic and treated conservatively first with…
NPO, TPN, stoma appliance, octreotide
Surgical options for fistula
Resect bowel segment containing fistula and perform primary anastamosis
MCC SBO in virgin/non-virgin abdomen
Virgin: SBO/Hernia, LBO/Cancer
Non-virgin: SBO/Adhesions, LBO/Cancer
Why do you see air with SBO
Swallowed nitrogen
What percentage of partial vs full SBO are cured by conservative management
80% vs 40%
Surgical indication for SBO
Progressive pain, peritonitis, fever, leukocytosis, failure to resolve
A gallstone ileus is caused by…
Fistula between gallbladder and duodenum second part
Meckel’s diverticulum is caused by…
Failure of closure of omphalomesenteric duct to close
50% of painless lower GI bleeds in children < 2 years old
Meckel’s
Most common tissue found in Meckel’s
Pancreatic; however gastric can cause symptoms
Management of duodenal diverticula
Rule out gallbladder-duodenal fistula; observe unless perforated, bleeding, obstructive, symptomatic
(D>J>I)
Extra-intestinal manifestations of Crohn’s
Arthritis, arthralgia, pyoderma, ocular, growth failure, megaloblastic anemia B12/folate
Rectal sparing in Crohn’s
True
Most commonly involved bowel segment in Crohn’s
TI
Crohn’s vs. UC
Transmural inflammation, skip lesions, cobblestoning, deep ulcers, creeping fat
Meds for Crohn’s
Remicade (infliximab) Sulfasalazine, loperamide, steroids; Flagyl; TPN
What percentage of Crohn’s patients evenutally need an operation
90%
Do you perform lateral sphincteroplasty in patients with Crohn’s disease?
No
Can you do a pouch or ilio-anal anastamosis for patients with Crohn’s disease?
No
Serotonin is produced by…
Kulchitsky cells – enterochromaffin cell or argentaffin cell
5-HIAA is a breakdown product of serotonin
Carcinoid syndrome
Liver mets: flushing, diarrhea
Asthma-like, R heart valve lesions
(Liver usually clears serotonin(
Octreotide scan
Used for carcinoid
Most common site for carcinoid
Appendix
Appendiceal carcinoid treatment
< 2 cm: appy
> 2 cm: R hemi
CTX for carcinoid
Strptozocin, 50FU
Octreotide; palliation
Treatment for salmonella enteritis
Bactrim
* RLQ, diarrhea, fever, HA, mac pap rash, leukopenia, bleeding/perf
In a child – * RLQ, diarrhea, fever, HA, mac pap rash, leukopenia, bleeding/perf rare
Salmonella typhoid enteritis
MCC electrolyte abnormality a/w ileus
K
MCC death in appendix mucocele
Malignant small bowel obstruction
T/F Regional ileitis can mimic appendicitis
True; 10% go on to develop Crohn’s
Should you open for an appendix mucocele?
Yes; rupture –> pseudomyxoma peritonei
MCC acute abdominal pain in 1st trimester
Appendicitis
What trimester is acute appendicitis most likely?
Second
When is acute appendicitis most likely to perforate in pregnancy?
Third trimester
Is the appendix displaced cephalad during pregnancy?
Yes
What percentage of fetal death with ruptured appendicitis in pregnancy?
35%
Women with suspected appendicitis should always have…
b-HCG and abdominal ultrasound to r/o pregnancy
What is the general sequence of symptoms a/w acute appendicitis
1st: Anorexia
2nd: Peri-umb abdominal pain
3rd: Vomiting
What does a CT scan show in acute appendicitis?
Diameter > 7 mm; Wall thickness > 2mm; no contrast in lumen
Most likely location of perforation of appendicitis
Midpoint of anti-meseneric border
Most common cause of acute appendicitis in children
Lymphoid hyperplasia; can follow a viral illness
Most common cause of acute appendicitis in adults
Fecalith
What is the pathophysiology of ruptured appendicitis?
Luminal obstruction, distension of appendix, venous congestion and thrombosis, ischemia, gangrene, rupture
Treatment of ruptured appendicitis
Perc drainage and interval appendectomy – need to r/o perforated cecal cancer
Do you need to repair a parastomal hernia?
No – unless symptomatic
Most common stomal infection
Candida
What is diversion colitis?
Secondary to lack of SCFA’s – treatment is SCFA enemas
Most common cause of stoma stenosis
Ischemia; dilate if mild
Most common cause of fistula near stoma site
Crohn’s
Are gallstones more common in patients with ileostomy
Yes – loss of bile salts
Are uric acid stones more likely in patients with ileostomy?
Yes; loss of bicarb
Where are most small bowel adenomas found?
Duodenum; can p/w bleeding, obstruction; need resection when identified
Is Peutz-Jeghers syndrome AD or AR?
AD: hamartomas throughout GT tract (small and large bowel); mucocutaneous melanotic skin pigmentation; patients have increased extra-intestinal malignancies,; MC – breast cancer, small risk of Gi malignancies
Do patients with Peutz-Jeghers get prophylactic colectomy?
No
