GI pathology - Devaraj Flashcards
Dermatitis herpetiformis is seen in what condition?
Celiac disease.
Path report says:
villous blunting
increased intraepithelial lymphocytes
lymphoplasmacytosis of the lamina propria
Consider what diagnosis?
Celiac.
Celiac patients who eat gluten are at increased risk for what malignancy?
enteropathy-associated T-cell lymphoma (Mnemonic: EAT Lymphoma)
MIddle aged male with diarrhea, weight loss, malabsorption with abundant foamy macrophages packed into the lamina propria. What organism causes this pathology?
Tropheryma whippeli causes small bowel whipple disease.
Blockage of lymphatic transport causes malabsorptive diarrhea.
Path report says:
Villous blunting but no ulceration
Intraepithelial lymphocytes
Numerous protozoa bound to brush border, but no invasion.
Diagnosis? What symptoms will the patients likely have?
Giardia lamblia
7-14 day incubation period
Chronic diarrhea, malabsorption, flatulence, weight loss, may cause intermittent symptoms
Tx for Giardia?
Metronidazole. (Flagyl)
Gram-negative bacteria; major cause of diarrhea worldwide
A leading cause of bacterial foodborne illness in US
Produces a watery diarrhea +/- blood
Found in contaminated meat (poultry), water and unpasteurized dairy
Campylobacter enterocolitis.
C. jejuni or C. fetus (immunosupressed/neonates)
[birds pooping on the milk lids]
Gram-negative bacilli transmitted through food and water
Important cause of food poisoning and traveler’s diarrhea
Abdominal pain, headache, fever
Abdominal rash and leukopenia
Diarrhea (not until 2nd week of infection) initially watery then bloody
Characteristic pathology most commonly seen in the ileum, colon, appendix and Peyer’s patches.
Perforation and toxic megacolon possible
Salmonella typhimurium causes typhoid fever.
[Typhoid Mary]
Mild self-limited gastroenteritis
Endoscopy: mucosal redness, ulceration and exudates
Non-typhoid salmonella species. Generally self-limited
[cucumber outbreak, currently]
Non-invasive, toxin-producing, contaminated hamburgers
Bloody diarrhea, severe cramps, mild or no fever, sometimes renal failure (HUS)
On endoscopy: edema, erosions, ulcers, hemorrhage (right colon mostly)
Deadly outbreaks
Enterohemorrhagic E. coli (O157:H7 is the most common strain)
[Jack-in-the-box]
What is the most common cause of pseudomembranous colitis?
Clostridium difficile.
Describe the pathophysiology of C. difficile
Disruption of normal colonic flora by antibiotic allows C. difficile overgrowth → toxins released cause disruption of epithelial cytoskeleton, tight junction barrier loss, cytokine release and apoptosis
Adherent layer of inflammatory cells and mucinous debris at sites of colonic mucosal injury–>pseudomembrane (hence the name)
15 month old child with extreme watery diarrhea. Diagnosis?
Rotavirus. Most common cause of severe childhood diarrhea and diarrheal mortality worldwide.
Selectively infects and destroys mature enterocytes → villus surface repopulated by immature secretory cells → loss of absorptive function → net secretion of water and electolytes → osmotic diarrhea –>DEHYDRATION
2 vaccines available, so outbreaks less common.
Associated with a severe dysentery-like, fulminant colitis
Cecum most commonly affected; “flask-shaped” ulcers in mucosa. Protozoa visible in the stool histology.
Entamoeba histolytica
10% of world’s population is infected with E. histolytica parasite
One of most common parasites in humans
Most common in tropics
Ingested from soil contaminated with (Human) feces
Obstruction, perforation, growth retardation
Giant worms (up to 20cm) can be identified
Ascaris lumbricoides (roundworm)
