Small Bowel Flashcards
How does small bowel get its blood supply
From superior mesenteric artery
Drainage of small bowel
superior mesenteric vein, which drains into portal vein, into liver
Lymph drainage of small intestine
Goes through regional lymphatics to the cisterna chyli
Small intestine innervation
Parasympathetic nerves from right vagus, sympathetic nerves from greater and lesser splanchnics (visceral pain)
Layers of small intestine from lumen outwards
Mucosa, submucosa, muscularis, serosa
What does mucosa layer of small intestine contain
plicae circulares, villi, microvilli, crypts of lieberkuhn
which layer of small intestine contains the nerves and blood vessels? Is also the strongest layer
submucosa
Muscularis layer of small intestine contains…
both longitudinal and circular muscles
As you go from jejunum to ileum, what changes occur?
vascular arcades become more complex, lumen narrows, and circular mucosal folds become shorter and fewer
IBD major divisions
Crohn’s dz and ulcerative colitis
What are independent risk factors for crohn’s disease
smoking and high sugar
Which site is most frequently affected in Crohn’s disease
terminal ileum
Skip lesions seen in Crohn’s or UC?
Unique to Crohn’s
Creeping fat sign unique to…
Crohn’s disease
Patient presents wtih diarrhea, recurrent acute abdominal pain, anorectal lesions, anemia, malnutrition. Abdomen pain releived by defecation. Thickened bowel wall, stricture formation, “creeping fat,” in mucosa- pinpoint hemorrhages, cobblestoning, aphthous ulcers. Malaise, weight loss, fever. Systemic manifestations include pyoderma gangrenosum, uveitis, bone and joint lesions, pericarditis, Dx?
Chrohn’s
Signs and symptoms in Crohn’s
MACARDS- malnutrition, anemia, constitutional symptoms, anorectal lesions, recurrent and acute abdominal pain, diarrhea, and systemic manifestations
diarrhea in Crohn’s
continuous or intermittent. If non-bloody, SB involved. If bloody, think colon.
abdominal pain in crohn’s
chronic pain- mild, following meals, in low mid abdomen, relieved by defecation. acute pain- RLQ- TI involved usually
Acute RLQ pain in crohn’s mimics..
appendicitis
constitutional effects in crohn’s
lassitude, malaise, weight loss, fever
anorectal lesions in crohn’s
chronic anal fissures, large ulcers, edematous skin tags, complex fistulas, and recurrent peri-rectal abscesses
anemia in crohn’s
iron deficiency anemia, macrocytic anemia, vitamin B12 or folate deficiency. May see angular cheilitis
signs of malnutrition in crohn’s
steatorrhea, chronic partial obstruction, decreased oral intake (hurts when eating), vitamin D and zinc deficiency common, protein-losing enteropathy, growth retardation in children
Labs in Crohn’s
Prometheus test for IBD. tests for antibodies include ASCA, I2, ompC, CBir1 which will be elevated in Crohn’s. pANCA higher in UC
Xray signs of Crohn’s
String sign- stricture through segment of small bowel. and cecal narrowing
Medical tx in crohn’s
aminosalicylates, anti-TNF alpha, antibiotics, immunosuppressives, steroids
Key guideline when performing surgery in crohn’s
preserve intestinal length- only take out what is absolutely necessary. If take too much out, patient will be on TPN (total parenteral nutrition) forever
Crohn’s has no surgical or medical cure. T or F?
TRUE!
Acute form of colonic distension in which colon dilates and perforates
Toxic megacolon
What other anatomical part of GI tract is also involved in UC besides colon?
Rectum usually involved
Backwash ileitis may be observed in…
UC
Diagnosis of UC by
Endoscopy- loss of vascular pattern, granularity, friability, hyperemia, ulceration. no patches of normal mucosa. Barium enema can help diagnose- “lead pipe” - loss of haustral markings, pseudopolyps, fine serrations
apple core lesion -
stricturing in UC should raise suspicion of cancer
Truelove and Witt classification
classifies UC severity
How many stools per day are mild, severe, vs. fulminant
Less than 4 stools/day= mild UC. More than 6/day, severe diarrhea. More than 10 day, fulminant diarrhea
Medical tx of UC
Avoid NSAIDS, lactose. Sulfasalazine, steroids.
Indications for Surgical tx of UC
acute severe disease that doesn’t respond to medical tx, emergently in perforation, urgently in toxic megacolon, hemorrhage, refractory fulminant colitis
What are Ladd’s bands
Congenital bands often discovered during infancy. Occur with malrotation causing obstruction of small bowel
Most common surgical disorder of the small intestine due to
obstruction
Mechanical obstruction of small bowel
Simple obstruction, strangulation, and closed loop obstruction
Causes of small bowel obstruction
A New FIV Hurray Voila!- volvulus, cystic fibrosis, adhesions, neoplasm, stricture, foreign bodies, Gallstone ileus, Hernia, hematoma, IBD, intussusception
Most common cause of small bowel obstruction
adhesion- caused by inflammation of the abdomen or by surgery
“Target sign” on CT indicative of
intussusception in adults
intussusception more common in which population
children.
Tx of intussusception in children
Barium enema- diagnostic and tx
Most common site of foreign body small bowel obstruction is…
ileocecal valve
Patient presents with vomiting, abdominal pain, and obstipation. She has high pitched bowel sounds, peristaltic rushes, gurgles, tympanitic percussion, and distension. Tachycardia, dehydration. Xray shows air fluid levels and stair stepping. Amylase elevated, hemoconcentration, electrolyte abnormalities, leukocytosis. Dx?
smal bowel obstruction
proximal vs. distal SBO differences in vomiting, obstipation, and abdominal pain
vomiting in Proximal SBO occurs early and is profuse, obstipation late. distal SBO- vomiting late and feculent, obstipation early
SBO tx
NGT, IVF, NPO, pain control. complete SBO- surgery. partial SBO- bowel rest.
Patient presents with severe continous pain, hematamesis, peritoneal signs on exam, leukocytosis, lactic acidosis. Bowel blocked in 2 places. Dx
Closed loop obstruction
Patient with sudden severe diffuse abdominal pain but physical exam is normal. CT also negative. could be..
acute mesenteric ischemia
Gastroenteritis tx
Viral- so NO ABX. stool studies, hydration, replace electrolytes, avoid anti-diarrheal medication
Most common small bowel benign tumors
adenomas
Most often found benign small bowel tumors (most symptomatic)
GIST (like leiomyomas and leiomyosarcomas)
Most common primary malignant small bowel tumor
adenocarcinoma
What predisposes someone to primary SB lymphoma in proximal jejunum?
celiac disease
Small bowel malignant neoplasms
primary malignant tumors, metastatic malignant tumors, and carcinoid tumors
carcinoid small bowel neoplasms arise from… and associated wtih….
arise from enterochromafin cells. associated with MEN type 1 and 2
what is most common site in carcinoid small bowel neoplasms
appendix
10% of patients with carcinoid tumor have “carcinoid synrdrome” which includes
bronchoconstriction, diarrhea, flushing, and R sided heart valve disease from collagen deposition
Which carcinoid tumors would you more likely see carcinoid syndrome in?
Ovarian, bronchail carcinoids, and hepatic metastases more than intestinal carcinoids- circulation related
How to test for lactose intolerance
Lactose breath test OR give 100g oral lactose, check blood glucose every 30 min x 2 hours to see if it rises more than 20mg/dl over that time
Tx of lactose intolerance
lactose free diet, supplementation of vitamin D, calcium, and riboflavin
tx for celiac disease
gluten free diet
diagnosis of celiac disease
igA endomysial antibodies, igA tTG antibodies
What part of GI tract does celiac disease damage?
Diffuse damage to proximal SB
