Path-Diarrhea Flashcards
this infection results in infiltration of small bowel mucosa with macrophages that cannot destroy the bacteria, resulting in abundant pale granular cytoplasm
whipple’s dz
macrophage cytoplasm in whipple’s dz is highlighted with this stain
PAS (look DARK pink all over)
in whipple’s dz, expansion of the lamina propria with numerous macrophages results in the impression of a…
flat mucosa
what is found scattered throughout the lamina propria in Whipple’s dz?
variably-sized clear spaces, representing lipid droplets
who get’s whipple’s dz?
males 8-10x more likely, usually white, 40-50 yrs old
microbiology of whipple’s dz bacteria
actinomycetes, gram positive bacteria that can form filaments
what diarrhea pattern is seen in whipple’s?
chronic and malabsorptive
CMV/HSV infection most common in _____
immunocompromised
tissue damage from CMV is due to..
ischemic necrosis of mucosa and ulceration
what cells are usually affected by CMV
endothelial cells and fibroblasts
microscopic findings of CMV
cytomegaly, eosinophilic inclusions (intranuclear and cytoplasmic)
which parts of the GI tract are affected by HSV
squamous epithelium of esophagus or anal canal
gross pathology of both CMV and HSV shows?
small, shallow ulcers with white necrotic debris and red border
basophilic “ground-glass” intranuclear inclusions found in multinucleated epithelial cells suggests?
HSV infection
4 M’s of HSV (Herpetic viral cytopathic effect)
- Megaly (big), 2. multinucleated, 3. nuclear molding, 4. chromatin margination (ground glass nucleoplasm with viral particles)
this protozoan parasite causes self-limiting acute, watery, non-bloody diarrhea in immunocompetent
cryptosporidium parvum
how would you detect crypto histologically?
tiny, round PAS+ organisms inside vacuoles located on the brush border of many GI organs
host response to crypto
increased lymphocytes in lamina propria, mild epithelial damage (can cause villous atrophy and neutrophilic infiltration in severe cases)
this infection causes increased shedding of infected cells, resulting in surface epithelium with even worse malabsorption
cryptosporidium parvum
Of crypto and giardia, which parasites resist chlorination? Are removed by filtration?
both; giardia
pathogenesis of giardia
trophozoites adhere to mucosal surface, forming physical barrier to absorption and damaging brush border such that short-term enzyme deficiencies develop
how can giardia trophozoites be recognized on histo?
pear or leaf shaped parasites floating in mucus and on mucosa; attach to mucosa by ventral sucker disc
transmission of giardia
fecal-oral –> outdoorsy ppl consume fresh water that contains cysts (cysts reproduce to form trophozoites inside human), also daycares, homosexuals
imprint cytology with this stain shows pear-shaped giardia trophozoites
Giemsa (look purply-blue)
entamoeba is transmitted by?
fecal-oral
most common site for entamoeba
cecum
gross pathology of entamoeba
friable, red mucosa and ulceration resembling IBD
microscopic findings of entamoeba
flask-shaped ulcers extend through muscularis mucosae
complications of entamoeba infection
spread to liver, causing abscess
colon biopsy of entamoeba shows?
trophs containing ingested RBCs (look like macrophages)
entamoeba cysts in the stool can be stained with?
PAS stain
chronic cholitis comes in two forms?
bloody or watery
chronic bloody diarrhea suggests?
IBD or neoplasm
chronic watery diarrhea suggests?
microscopic colitis (lymphocytic +/- collagenous)
histology of microscopic colitis shows?
preserved architecture with lymphocytes in epithelium +/- thickened subepithelial collagen band
what other disease is associated with lymphocytic colitis
celiac disease
best way to visualize collagenous colitis
trichrome stain
where do lymphocytes localize in lymphocitic colitis
surface of epithelium and in glands
pathophysiology of celiac disease
immune mediated enterocyte damage -> crypt cells fail to regenerate -> shortened villi (note: patchy)
where is celiac dz most severe?
distal duodenum and proximal jejunum (take multiple biopsies due to patchy nature)
histologic findings in celiac
villous blunting (short with fused microvilli) with long crypts, increased lymphocytes and plasma cells in lamina propria, increased lymphocytes in epithelium
dx of celiac dz
small bowel biopsy, gluten-free trial, serologic testing with TTG, IgA
