GI Pathology Small & Large Bowels Flashcards
What is Crohn’s Disease?
Chronic inflammatory disorder of unknown cause, usually affecting the terminal ileum and/or proximal colon
- common in young adults
- involves all layers of GI tract
Diffuse inflammation causes bowel loops to bind together
Ulceration is common, as well as fistulas to bowel or other organs
Involves all layers of the GI tract and may have healthy and diseased areas interspersed.
What is the common radiographic appearance of Crohn’s Disease? (Barium study)
Irregular thickened & distorted mucosal folds, string sign (narrowing stretch of bowel with no mucosal pattern), skip lesions (diseased segments separated by healthy), cobblestone appearance (transverse and longitudinal ulceration)
Transverse and longitudinal ulceration produces a characteristic appearance.
What causes Small Bowel Obstruction?
Adhesions, hernias, intussusception, volvulus, tumors, vascular insufficiency
Can lead to ischemia and necrosis of bowel segments.
What is the 3-6-9 rule in relation to bowel obstruction?
Small bowel: <3 cm, large bowel: <6 cm, appendix: <6 mm, cecum: <9 cm
Above these dimensions, the bowel is generally considered dilated.
What is Adynamic (Paralytic) Ileus?
Fluid and gas do not progress normally through a non-obstructed bowel
Can be caused by post-op, peritonitis, medication, or trauma.
What is the radiographic appearance of Localized Ileus?
Isolated distended loop (sentinel loop)
Due to adjacent inflammatory process.
What are the potential causes of Bowel Perforation?
Obstruction, adynamic ileus, appendicitis, diverticulitis, hernia, cancer, gallstones
Can lead to internal bleeding, peritonitis, and sepsis.
What is Intussusception?
Telescoping of one part of the intestinal tract into another
Most common site in children is the ileocecal valve.
What is a Hemangioma?
Benign vascular tumors occurring along the GI tract
Most often found in the small bowel.
What defines Diverticulosis?
Presence of diverticula, which are out-pouchings of mucosa and submucosa
Often caused by a lack of fiber in the diet.
What is Diverticulitis?
Inflammation of diverticula, often leading to complications
Can cause peri-diverticular abscess or fistula formation.
What are the characteristics of Sessile Polyps?
Flat against colon wall, irregular lobulated surface, more likely to be malignant
Indicative of cancer if over 2 cm in diameter.
What is Ulcerative Colitis?
An inflammatory bowel disease that primarily affects the mucosal layer of the colon
Often begins in the rectosigmoid area.
What is Toxic Megacolon?
Extreme dilation of part or all of the large colon due to ulcerative colitis
Can lead to spontaneous bowel perforation.
What is the peak age for Colorectal Cancer diagnosis?
50-70 years
Early diagnosis is critical for the best outcomes.
What does Annular Colorectal Carcinoma look like on imaging?
Apple-core or napkin ring filling defect
Most common bowel cancer.
What are the causes of Large Bowel Obstruction?
Primary colon cancer, diverticulitis, volvulus
Forms more slowly than small bowel obstruction.
What is Volvulus?
Twisting of the bowel on itself that may lead to abdominal obstruction
Most frequently involves the cecum and sigmoid colon.
What is Imperforate Anus?
Congenital lack of anal opening
Often associated with a distended bowel.
