Small and Large Bowel Pathologies Flashcards
Chronic inflammatory disorder with unknown cause
Involves ALL layers of GI tract
Chron’s disease
Who are most commonly affected by crons?
Young adults
Chron’s disease causes
- diffuse inflammation that causes bowel loops to bind together
- Ulceration and fistulas (common)
- interspersed healthy and diseased areas
- diarrhea
- blood in stool
- abdominal pain & cramping
- weight loss with appetite loss
- pain or drainage near anus (if fistula is there)
Radiographic appearance of Chron’s disease
- irregular thickened mucosal folds
- string sign
- skip lesions
- transverse and longitudinal ulceration, looks like cobblestone
- (CT) thick mucosal walls
What is the string sign?
narrowed stretch of bowel without mucosal pattern
What is skip lesions?
Diseased segments separated by healthy segments
Blockage of the small intestine, a mechanical obstruction
Small bowel obstruction
What causes small bowel obstructions?
due to adhesions from
- previous surgeries or peritonitis
- hernias
- intussusception
- volvulus
- tumors
- vascular insufficiency
Small bowel obstruction may cause:
- Ischemia which leads to necrosis of the bowel segment
- perforation
- sepsis
- peritonitis
Symptoms of small bowel obstruction:
- pain
- cramping
- vomiting
- feeling full and loud sounds in belly (gassy)
What type of obstruction allows some liquid and gas to pass through?
low grade / Partial obstruction
What type of obstruction blocks all passage of bowel contents?
high grade / complete obstruction
What type of obstruction indicates the presence of a physical barrier to movement?
Simple obstruction
What type of obstruction shows compromised circulation to a segment of bowel which causes ischemia, infarction and potential perforation?
Complicated Obstruction
What type of obstruction means the lumen of the bowel is blocked off at two points which prevents bowel contents from moving forward or backward?
Closed loop Obstruction
What type of obstruction means obstruction at one point that interferes forward movement of bowel contents
Open-ended Obstruction
What is the 3-6-9 Rule
3-6-9 rule is the benchmark for normal bowel diameter, any greater means its dilated:
- small bowel 3cm
- large bowel AND appendix 6cm
- Cecum 9cm
Radiographic appearance of small bowel obstruction:
- air fluid levels seen
- Bowel loop dilated near the obstruction
- Bowel loop collapsed past the obstruction
- May present step ladder or cascade
Fluid and gas (+ bowel contents) cant move forward normally through an unobstructed small (or large) bowel
Part or all of the bowel fails to start peristalsis
Adynamic (paralytic) ileus
What can adynamic (paralytic) ileus cause?
bowel perforation
Whats the difference between colonic and localized ileus?
colonic affects the entire colon, large AND small bowel
localized affects a small part of either bowels
Symptoms of Adynamic Ileus:
- abdominal pain
- bloating
- nausea
- vomiting
How do we treat adynamic ileus?
With NG tube and IV fluids
radiographic appearance of localized ileus:
one very distended bowel loop
radiographic appearance of colonic ileus:
- large amounts of gas and fluid dilated small and large bowel with no clear sign of obstruction
- can look like mechanical obstruction (CT is used to figure it out)`
Hole in the GI tract
Bowel perforation
potential causes for bowel perforation?
- obstruction
- adynamic ileus
- appendicitis
- diverticulitis
- hernia
- cancer
- gallstones
- Crohn’s disease
- ulcerative colitis
- penetrating injury
- severe vomiting
- medical procedures
What does bowel perforations cause?
- pain
- fever
- nausea
- vomiting
- internal bleeding
- peritonitis
- sepsis
Radiographic appearance of bowel perforation in X-Ray
- air in the abdomen, trapped under the diaphragm
Radiographic appearance of bowel perforation in CT
- concentrated bubbles of air near the bowel wall
- discontinuity of the bowel wall
Telescoping of one part of the intestinal tract into another because of peristalsis
Intussusception
What can intussusception cause?
- compromise vascular supply (ischemic necrosis)
- bowel obstruction in children
- belly pain
- nausea
- vomiting
Most common site of intussusception?
ileocecal valve, in children
Radiographic appearance of intussusception?
x-ray: coiled spring appearance on contrast enema
CT: target sign, 3 circles
US: donut-shaped lesion
Benign vascular tumors are known as?
Hemangiomas
where do GI hemangiomas occur?
anywhere along the GI tract, most commonly the small bowel, then the large bowel, then the rectum
Radiographic appearance of hemangiomas
contrast displacing mass on contrast study
Part of the abdominal contents, usually small bowel, protrude through a weak area of the abdominal wall at the inguinal canals
inguinal hernia
Radiographic appearance of inguinal hernia
protruding parts visible on imaging not within abdominal cavity
out-pouchings of mucosa and submucosa through the muscular layers at the weak points of the bowel
Diverticulum/Diverticulosis
Development of Diverticulosis is usually caused by:
lack of fiber and water in the digestive track
Diverticulosis may cause:
- lower GI bleed
- abdominal pain
- bloating
- constipation
- diarrhea
Where can diverticula appear?
esophagus or duodenum
Radiographic appearance of diverticulosis
- multiple round or oval outpouchings from the bowel
- thickened circular muscle may look like sawtooth configuration
Complication of diverticulosis, inflammation of diverticula
diverticulitis
How does diverticulitis occur?
fecal matter gets trapped in the out-pouchings and leads to perforation and inflammation
Diverticulitis may cause:
- production of peri-diverticular abscess
- formation of fistula to adjacent organs
symptoms of diverticulitis
- abdominal pain
- nausea
- vomiting
- constipation
Radiographic appearance of diverticulitis
- Similar to diverticulosis
- contrast leaking from diverticula
Benign neoplasms that project into the lumen of the bowel
Polyps
Where are polyps often found?
Mostly in the descending and sigmoid colons
Radiographic appearance of polyps:
- filling defect
- polyp appearance depending on the type (sessile, mushroom capped, pedunculated)
- Irregular lobulated surface
- lies flat against colon wall
- more likely to be malignant
Sessile polyp
Sessile polyps are indicative of cancer if…
it is over 2cm in diameter, causes puckering/indentation/retraction at site or growth on follow up exams
Smooth surface with long thin stalk
Pedunculated polyp
- Inflammatory bowel disease
- starts in rectosigmoid area and may spread to whole colon
- rarely involves small bowel and usually involves just the mucosal layer of colon
- can become cancerous
Ulcerative Colitis
Symptoms of ulcerative colitis:
- bloody diarrhea
- abdominal pain
- fever
- weight loss
Radiographic appearance of ulcerative colitis:
- grainy looking mucosa
- Thumbprinting sign (large nodular protrusions)
- collar button appearance (deep mucosal ulcerations)
- loss of haustral markings from muscle atrophy/spasm (lead pipe appearance)
- a complication of ulcerative colitis
- extreme dilation of part or all of large colon
Toxic Megacolon
What can toxic megacolon lead to?
- spontaneous bowel perforation
causes of toxic megacolon:
- perforation risk
toxic megacolon causes:
- swollen belly
- bloody and frequent diarrhea
- fever
- tachycardia
- signs of shock
Radiographic appearance of toxic megacolon:
huge air-filled colon
Cancer of the colon and rectum
Colorectal cancer
where is colorectal cancer often found?
in the rectum and sigmoid
What can colorectal cancer cause?
- polypoid mass or surround the colon
- ulceration
- metastasize
Symptoms of colorectal cancer
- change in bowel habits
- bloody stool diarrhea
- constipation
- abdominal pain
- weight loss
Radiographic appearance of colorectal cancer:
narrowed section of lumen with irregular contours and rigid tapered margins in barium exams
CT will show narrowing and a mass
what studies do we use to examine colorectal cancer?
- barium enema
- colonoscopy
- CT colonoscopy
Annular lesions surround the bowel from the outside
starts from flat plaque like tumors (saddle lesions) and are easily missed on exams
annular colorectal carcinoma
What is the most common bowel cancer?
annular colorectal carcinoma
Where does annular colorectal cancer commonly occur?
in the sigmoid
Radiographic appearance of annular colorectal carcinoma:
Barium enema will demo apple-core or napkin ring filling defect
What is the new gold standard for imaging/cancer detection of large bowel?
CT virtual colonoscopy
What is a large bowel obstruction?
obstruction of the large bowel
Forms slowly with less fluid and electrolyte disturbance
less severe compare to small bowel obstruction
could be from diverticulitis or volvulus
Bowel twists on itself and may lead to abdominal obstruction
Volvulus
Where does volvulus often occur
The cecum and sigmoid colon
Symptoms of volvulus:
- abdominal pain
- swollen belly
- bloody stools
- bilious vomit
Radiographic appearance of volvulus:
- BE is often used
- Volvulus at the cecum: looks distended and displaces the cecum and makes it look like a kidney
- Volvulus at the sigmoid: distended rectum with lumen looking like a bird’s beak (tapered towards volvulus area)
Bowel twists on itself
similar to another pathology but occurs during fetal development
malrotation of bowel/colon
Symptoms of malrotation of bowel/colon:
- abdominal distention
- pain
- vomiting (may have bile)
- constipation
- bloody stools
Radiographic appearance of malrotation of bowel/colon
Abnormal bowel locations on images
Is malrotation of bowel/colon a problem?
It can be depending on the severity
Lack of butthole
associated with distended bowel
Imperforate anus (anal atresia)
Radiographic appearance of imperforate anus:
- multiple dilated loops with gas
- absence of rectal gas
