Pathology of the Lower GI Flashcards
Celiac, whipple disease giardia
small bowel diseases
colitis, IBS, IBD, diverticular disease, appendicitis
large bowel diseases
Host factors associated with celiac
Class II HLA-DQ2 or HLA DQ8
type 1 DM, thyroiditis, Sjogren
Bulky fatty diarrhea, flatulence, weight loss, anemia, nutritional deficiencies, growth failure in children
Classical presentation of celiac disease
Microscopic findings in celiac disease
villous blunting, intraepithelial lymphocytes
extra-intestinal complaints with celiac disease
fatigue, Fe deficiency, pubertal delay, short stature, canker sore
triad of diarrhea, weight loss, malabsorption
arthritis, lymphadenopathy, neurologic disease
middle-aged or elderly white males
Whipple disease
Whipple disease microscopic findings
swollen macrophages –> villi distension
macrophages filled with Whipple bacilli (PAS stain)
protozoan parasite –> chronic diarrhea, malabsorption flatulence, weight loss
giardia lamblia
Pathology: “schools of fish” in the duodenum
giardia lamblia
Pathogenesis of C diff colitis
disruption of normal colonic flora by antibiotic –> C diff overgrowth –> toxins released –> disruption of epithelial cytoskeleton, tight junction barrier loss, cytokine release, apoptosis
Histology: pseudomembranes (adherent layer of inflammatory cells and mucinous debris at sites of colonic mucosal injury), denuded surface epithelium, mucopurulent exudates
pseudomembranous colitis
most common cause of severe childhood diarrhea and diarrheal mortality worldwide
rotavirus
rotavirus pathophysiology
selectively infects and destroys mature enterocytes –> villus surface repopulated by immature secretory cells –> loss of absorptive function –> net secretion of water and electrolytes –> osmotic diarrhea –> dehydration
flask-shaped ulcers in cecum mucosa
severe dysentery-like, fulminant colitis
entamoeba histolytica parasitic enterocolitis
Stool exam –> ova and parasites
helminth infection enterocolitis
Helminthic infections epidemiology
seen in nations with deficient sanitation systems, poor SES and hot, humid climates
parasites in tropics, ingested from soil contaminated with feces
roundworm –> obstruction, perforation, growth retardation
Histology: focal acute mucosal necrosis or full-thickness necrosis
ischemic colitis
normal endoscopy, chronic non-bloody watery diarrhea without weight loss
microscopic colitis
Histology: thickened subepithelial collagen layer
collagenous colitis
Histology: increased intraepithelial lymphocytes
lymphocytic colitis
Population with highest incidence of IBD
Female Ashkenazi Jews
Th1 mediated IBD
Crohn’s
Th2 mediated IBD
UC
Histology: crypt architectural distortion (chronic), cyptitis, crypt abscess
active chronic colitis (IBD)
outpouchings lined by mucosa, submucosa and variable amounts of muscularis propria
diverticulosis
diverticulitis histology
diverticulum becomes infiltrated with acute, then chronic inflammatory cells
extension of infection –> mucosal ulceration, pericolonic abscesses, fistulas
appendicitis histology
mucosal ulceration, transmural acute and chronic inflammation, extension of inflammation into the mesoappendix
