Ch. 17 Pathology: Infectious Enterocolitis Flashcards by Tanner KG

what is cholera?

disease caused by vibrio cholerae (gram-negative rod)

transmitted through contaminated drinking water

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what is the pathogenesis of cholera?

cholera toxin binds epithelial cell GM1 ganglioside

results in the opening of CFTR

cAMP inhibits the absorption of sodium and chloride

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what is the clinical presentation of cholera?

massive amounts of “rice-water” diarrhea with fishy-odor
dehydration
electrolyte imbalance

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what is campylobacter enterocolitis?

caused by campylobacter jejuni

the most common enteric pathogen in developed countries

cause of travel’s diarrhea

undercooked chicken, unpasteurized milk and contaminated water

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What is the clinical presentation of campylobacter enterocolitis?

watery or bloody diarrhea

enteric fever with bacteria proliferation

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people with HLA-B27 are prone to develop what symptom when infected with C. jejuni?

reactive arthritis

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What CNS complication is associated with C. jejuni infection?

Guillain-Barre syndrome: ascending demyelinating polyneuropathy

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what skin manifestation can occur with C. jejuni infection?

Erythema nodosum

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what is shigellosis?

enteric infection caused by Shigella bacteria

common throughout daycares, migrant workers, and nursing homes

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what is the pathogenesis of shigella?

predominately affects the left colon and ileum

organize within M cells overlying Peyer patches causing ulceration

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what is the clinical presentation of shigella?

1 week incubation period

watery diarrhea that progresses to dysentery

fever and abdominal pain

mimics new onset ulcerative colitis

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what should NOT be given to patients infected with shigella?

anti-diarrheals

*delays bacterial clearance

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what are some complications associated with shigella?

reactive arthropathy
hemolytic-uremic syndrome
toxic megacolon

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What are the two subtypes of salmonella?

typhoidal and non-typhoidal

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what is non-typhoidal salmonella?

caused by S. enteritidis

food poisoning by ingestion of contaminated food

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what is the clinical presentation of non-typhoidal salmonella?

clinically indistinguishable from other enteric pathogens

watery diarrhea or dysentery

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what is typhoidal salmonella?

caused by S. typhi or S. paratyphi
*Americans are vaccinated against S. typhi

an enteric disease that also manifests with flu-like symptoms

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what is the pathogenesis of thyphoid fever?

S. typhi are able to survive gastric acid and are taken up by M cells within Peyer patches of the terminal ileum

Peyer patches ulcerate

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what is the clinical presentation of typhoid fever?

anorexia
abdominal pain (may mimic appendicitis)
bloating
nausea and vomiting
blood diarrhea
rose spots on chest and abdomen

*short asymptomatic phase followed by bacteremia and flu-like symptoms

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what are the hallmarks of disseminated S. typhi?

enlarged spleen with pale red pulp, follicular markings, and phagocyte hyperplasia

liver contains macrophage aggregates called typhoid nodules

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What comlications can occur with disseminated S. typhi?

encephalopathy
meningitis
seizures
endocarditis
myocarditis
pneumonia
cholecystitis

colonization of what organ is associated with a chronic carrier state of S. typhi?

Gallbladder

*can cause gallstones also

who is at risk for disseminated S. typhi?

Cancer
Immunosuppresion
EtOH
CV disease
Sickle cell disease
Hemolytic anemia

what are sickle cell patients susceptible to developing when infected with salmonella?

salmonella osteomyelitis

what are the 3 species of yersinia?

Y. enterocolitica Y. pseudotuberculosis Y. pestis

what is the pathogenesis of yersinia?

invade and colonize within M cells of Peyer patches within ileum causing ulceration also invade appendix and right colon can mimic crohn disease and/or appendicitis

what enhances yersinia virulence and stimulates systemic dissemination?

iron *people with certain anemias or hemochromatosis are at increased risk for sepsis

what is enterotoxic E. coli?

principle cause of traveler's diarrhea due to contaminated food or water

what is enteropathic E. coli?

worldwide cause of endemic diarrhea

what is enterohemorrhagic E. coli?

E. coli O157:H7 and non-O157:H7 serotypes *inadequately cooked beef

what is enteroinvasive E. coli?

bacteriologically similar to Shigella transmitted via food, water, or person-to-person contact

what is enteroaggregative E. coli?

unique "stacked brick" morphology when bound to epithelial cells

what is pseudomembranous colitis?

antibiotic-associated colitis due to disruption of the normal colonic microbiota allows overgrowth of C. diff

what is the clinical presentation of pseudomembranous colitis?

fever leukocytosis abdominal pain/cramping watery diarrhea (may be occult blood +) protein loss and dehydration!

what is the potentially fatal complication of pseudomembranous colitis?

toxic megacolon

what is whipple disease?

rare, multivisceral chronic disease described as intestinal lipodystrophy associated with farmers and other occupations with soil or animal exposure

what is the clinical presentation of whipple disease?

TRIAD: diarrhea weight loss arthralgia

what is the morphologic hallmark of whipple disease?

dense accumulation of distended, foamy macrophages in the small intestine lamina propria macrophages are periodic acid-Schiff (PAS) +

what is the most common cause of gastroenteritis outbreaks?

norovirus usually occurs in schools, hospitals, nursing homes and cruise ships

what age group is most susceptible to rotavirus infection?

6-24 month old babies *breast milk provides immunity until 6 months old

ascaris lumbricoides

nematode parasite larvae are ingested and migrate to the lungs larvae are coughed up and swallowed where they mature in the GI tract

strongyloides

nematode parasite reside in soil and can penetrate broken skin migrate to GI tract

intestinal hookworm

larvae penetrate the skin and travel to lungs larvae will migrate up the trachea and are subsequently swallowed mature worms attach to duodenal mucosa *can cause anemia and hemorrhage

enterobius vermicularis

pinworms! ingested and travel to the external anus where they lay eggs *itchy butthole*

schistosoma spp.

found in water and penetrate skin eggs become trapped within mesenteric veins and cause obstruction

taenia spp.

"pork tapeworms" ingested by eating raw or undercooked pork larvae attach to the intestinal mucosa and feeds on intestinal contents *can cause B12 deficiency

Diphyllobothriid spp.

"fish tapeworms" ingested by eating infested fish larvae attach to the intestinal mucosa and feeds on intestinal contents *can cause B12 deficiency

Entamoeba histolytica

causes amebiasis reside within the colon but can travel to liver, lungs, or brain via bloodstream

giardia lamblia

flagellated protozoan the most common parasitic pathogen in humans spreads by infested water or food washed with infested water *typically found in streams and lakes

cryptosporidium

spread via infected water supply attaches to brush boarder