Large Intestine

Question 1

Hirschprung’s disease

Answer 1

Most common cause of congenital intestinal obstruction
Incidence (1/5000 – 1/8000), M:F = 4:1, in 10% of down syndrome patients
Absence of ganglion cells in Meissner and Auerbach’s plexus, rectum is always affected
Dilatation and hypertrophy proximal to aganglionic segment (congenital megacolon)

Question 2

Diverticular disease

Answer 2

Flask-like structures (95% sigmoid colon) extending from lumen thru muscular layer
Pathogenesis – lack of dietary fiber leads to sustained bowel contractions and increased intraluminal pressure, herniation of colonic wall

Question 3

Colitis

Answer 3

diarrhea (mucoid, bloody), abdominal pain (usually below umbilicus), abdominal cramps, tenesmus

infections (bacteria, viral, protozoal), necrotizing enterocolitis, antibiotic-associated colitis (pseudomembranous colitis), ischemic colitis, idiopathic (IBD)
Most common is E.Coli related – EHEC

Question 4

Pseudomembranous colitis

Answer 4

broad spectrum antibiotic use, caused by C. Diff (*KNOW FOR EXAM), toxin-mediated damage, colon (rectosigmoid) exhibits raised yellow plaques
Fibrinopurulent-necrotis debris (

Question 5

Ulcerative colitis

Answer 5

intermittent rectal bleeding, bloody diarrhea, and abdominal pain
Typically continuous colonic involvement

Question 6

Crohn’s disease

Answer 6

granulomatous colitis
transmural involvement by an inflammatory process
more variable
wall is thickened
symptoms than UC that include abdominal pain, fatigue, weight loss, and fever
Typically patchy transmural involvement

Question 7

Idiopathic inflammatory bowel disease

Answer 7

Includes Crohn’s disease (CD) and ulcerative colitis (UC)
Chronic relapsing, inflammatory disorders of obscure origin
Crohn’s disease – granulomatous inflammation which can affect any part of GIT from mouth to anus
Ulcerative colitis – non-granulomatous inflammation limited to colon

Question 8

Ulcerative colitis

Answer 8

Ulcero-inflammatory disease (non-granulomatous inflammation)

and affecting mucosa and submucosa
Extends in continuous fashion
Associated with primary sclerosing cholangitis (PSC), HLA-DRB1 association
10% cases back wash ileitis, serosa is usually normal, mucosa red granular and friable, broad based ulcers, isolated islands of regenerating mucosa bulge in between to create pseudopolyps

Question 9

IBD

Answer 9

relapsing disorder, attacks of bloody mucoid diarrhea, lower abdominal pain, abdominal cramps, tenesmus, flare-ups with physical and mental stress, fever and weight loss in severe cases, features of malabsorption, features of subacute intestinal obstruction (in SI)

Question 10

Ischemic bowel disease

Answer 10

common in elderly, mild features in only mucosal involvement (N/V and bloody stools), transmural involvement (severe abdominal pain/tenderness, gangrene, perforation, peritonitis, shock and vascular collapse, high mortality (50-75%)

Question 11

Acute appendicitis

Answer 11

nflammation of the appendix
Underlying obstruction of the lumen
adolescents and young adults, pain is most common symptom (initially periumbilical then localizes to right quadrant), N/V, tenderness (McBurney’s point), mild fever, leukocytosis (neutrophilia)
Complications – perforation, peritonitis, periappendiceal abscess, liver abscess, bacteremia