Lower GI- PART III WK 7 Flashcards
definition of Acute Intestinal Peforation
EMERGENCY
Any part of GI tract can perforate, spilling gastric and intestinal contents into abd cacity
Causes of Acute Intestinal Peforation
Common causes: blunt or penetrating trauma, foreign bodies
Causes in SI: duodenal ulcer, corrosives, strangulation of bowel, acute appendicitis
Causes in colon: obstruction, diverticulitis, IBD, toxic megacolon
SSX of Acute Intestinal Peforation
sudden and catastrophic: severe generalized abd pain, tenderness, signs of shock, N/V, anorexia
In pts with underlying GI disorder, looks like “worsening” (more gradual and localized pain)
PE of Acute Intestinal Peforation
bowel sounds- quiet to absent
peritoneal signs - guarding and rigidity
work up for acute intestinal perforation
free air seen (usu in SI) on abdominal xray or abdominal CT
Gastroenteritits
Inflammation of lining of stomach, SI, and colon (from infections most commonly)
typically self-limiting, but can be serious in young, elderly, immunocompromised
Hx: ask re ingestion of potentially contaminated food or water, travel, contact with similarly ill person, medication use (recent antibiotic use)
Normal Intestinal Microflora
The typical GI tract is inhabited by 500 different bacterial species
Stomach and proximal small bowel: few bacteria because of acidity
Jejunum: lactobacilli, enterococci, gram pos aerobes, facultative anaerobes
Terminal ileum: enterobacteria, coliforms
Colon: anaerobes- bacteriodes, lactobacillus, clostridium, bifidobacterium
General SSX of Gastroenteritis
varies. sudden onset of N/V, anorexia, abdominal cramps and diarrhea
may be malaise and myalgia
PE & work-up for Gastroenteritis
PE: Distended abdomen, tenderness, borborymi
Work up: hemoccult, fecal WBCs, O&P, culture -> stool test
Rapid enzyme assays: viral antigens, Shiga toxin, CBC, CMP
factoids about Viral Gastroenteritis
comprises 30-40% of infectious diarrhea in US
viruses infect enterocytes in SI villi leading to transudate of fluid/salt into lumen, causes watery diarrhea, stools rarely contain blood or mucus
causes of Viral Gastroenteritis
Rotovirus Norovirus Astrovirus Enteric Adenovirus CMV and Enterovirus (in immunocompromised)
Rotovirus
most common cause of infectious diarrhea worldwide
highly contagious: fecal-oral route
prevalence throughout yr; peak incidence occurs in winter months
severe, dehydrating diarrhea in kids (can be deadly, peak incidence 3-15 mo), mild in adults
SSX: vomiting, fever >102, sx can last 5-7 days
Norovirus
older children and adults, year -round incidence
can be epidemic with water and food-borne outbreaks, highly contagious
SSX: acute onset vomiting, abdominal cramps, diarrhea, fever, HA, lasts 1-2 days
Astrovirus
infants and young kids, winter months, fecal-oral route
SSX: similar to rotavirus
Enteric Adenovirus
kids <2yo affected, year-round/summer, fecal-oral route
SSX: diarrhea followed by mild vomiting. Diarrhea lasts 1-2 weeks
CMV and enterovirus
can cause gastroenteritis in immunocompromised
causes of Bacterial gastroenteritis
Exotoxin Enterotoxin Parasitic infections Fungal overgrowth Drug and Chemical-related gastroenteritis
Exotoxin
toxin secreted by microorganism and released into the environment then pre-formed toxin ingested in contaminated food
causing nausea, vomiting, watery diarrhea within 12 hrs of ingestion
minimal systemic sx (except botulinum)
sx abate within 36 hrs
stools have NO blood or WBCs
Types of Exotoxin
Staphylococcus aureus
Bacillus cereus
Clostridium perfingens
Clostridium botulinum
Staphylococcus aureus (an Exotoxin, a cause of bact gastroenteritis)
Staphylococcus aureus- most common food poisoning, toxin introduced by food-handlers
common foods involved: custard, milk products, potato sald, coleslaw, processed meat/fish at room temp
SSX: sudden, abrupts, severe vomiting 2-6 hr after ingesting, explosive diarrhea, abd cramps, rarely fever
course: last 3-6 hrs, usu complete recovery
Bacillus cereus (an Exotoxin, a cause of bact gastroenteritis)
Bacillus cereus- spore-forming organism found in soil
contamination of food before cooking which survive high heat
common foods: contaminated rice or meat
SSX: 2 distinct syndromes: emesis- 2-6 hrs after ingestion severe vomiting, abd pain with or without diarrhea, no fever no systemic sxs OR diarrhea- h-16 hrs, foul smelling, profuse with nausea, abd pain, tenesmus
course: resolves in 12-24 hrs
Clostridium perfringens (an Exotoxin, a cause of bact gastroenteritis)
Clostridium perfringens - spore forming anaerobe widely distributed in feces, soil, air, water
most toxin synthesized before ingestion, additional produced in GI after ingestion of contaminated beef, beef products, poultry
food inadequately pre-cooked and then reheated before served
SSX- watery diarrhea, foul smelling with severe, crampy abd pain, 8-26 hr after ingestion
course: self-limited, resolves in 24-36 hrs
Clostridium botulinum (an Exotoxin, a cause of bact gastroenteritis)
Clostridium botulinum- (3 exotoxin types- A, B, E)
responsible for 1/3 of deaths from food borne dz
types A, B associated with improperly prepared home-canned non-acidic fruits & veg - string beans, corn, mushroom, spinach, olives, beets, asparagus
Type E assoc with smoked freshwater fish
boiling in water for 15 min can inactivate exotoxin
SSx- incubation 4 hr - 8 days after ingestin
phase 1- vague- short period of fatigue, N/V, abd cramps, darrhea
phase 2- visual- diplopia, decreased acuity, PERRLA, ptosis
phase 3- neurological- descending weakness or paralysis, dysarthria, dysphagia, weakness of trunk and extremities, sensorium unaffected, normal or low temp
blood, urine, CSF normal
Course: 65% mortality 2-9 days following ingestion
with tx < 10% supportive to prevent respiratory impairment
DDX: polio, encephalitis, M. gravis, curare, belladonna poisoining
Enterotoxin
Cytotoxin produced by bacteria, specific for the mucous membrane of the intestine (in vivo). The toxin impair intestinal absorption, increases secretion of water and electrolytes, causing watery diarrhea
Types of enterotoxin
Cholera and non-cholera vibrio (endemic in Asia)
Enterotoxigenic Escherichia coli
Clostridium difficile “C diff”
Cholera and non-cholera vibrio (an enterotoxin, a cause of bact gastroenteritis)
any fecal contaminated water or food may cause
in US from contaminated saltwater crabs and freshwater shrimp, incubation 1-3 days after ingestion
SSX: sudden, painless, profuse, large volume, water diarrhea, no blood or mucus
usu no fever, abd pain, vomiting, tenesmus
water and electrolyte loss leads to thirst, oliguria, muscle cramps, weakness, cold, cyanotic skin, dehydration, hypotension, tachycardia
course: recovery in 7-10 days if rehydration is adequate
fatal in over 50% of untreated severe cases
Enterotoxigenic E. coli (an enterotoxin, a cause of bact gastroenteritis)
diarrhea caused by tissue invasion or via its enterotoxin
fecal/oral route of contaminated water or food, traveler’s pathogen
incubation: 1-3 days
SSX: profuse, watery diarrhea, lasts 3-5 days
Clostridium difficile “C diff” (an enterotoxin, a cause of bact gastroenteritis)
overgrowth of intrinsic organisms (post antibiotic) or infection by external source (soil, water, household pets)
cytotoxin and enterotoxin cause pseudomembranous colitis
commonly nosocomial dz
SSX: watery diarrhea, cramping abd pain, N/V are rare
Complication: Toxic Megacolon - dilated colon with fever, abdominal pain, tachycardia
PE: tender abdomen, absent bowel sounds
Work-up: elevated WBC, distended bowel seen on xray, Colonoscopy is contraindicated
Risk of perforation, sepsis, septic shock
Other possible causes: UC, Crohn’s, Entamoeba histolytica, Yersinia infx
Mucosal invasion
mucosal invasion by ingested organism- cause microscopic ulceration, bleeding, exudates, secretion of electrolytes and water
Stool has WBCs, RBCs, possibly gross blood
fever and prostration are common
diarrhea may be watery or bloody: watery > 1 liter/day, usu no fever, h/a, myalgia, or arthralgia; bloody usu with abdominal pain, tenesmus, N/V, fever, malaise
Types of mucosal invasion
Salmonella Campylobacter jejuni and fetus Shigella Enterohemorrhagic E. coli Yersinia enterocolitica
Salmonella (a mucosal invasion, a cause of bact gastroenteritis)
ingestion of undercooked chicken or eggs, unpasteurized milk, contact with reptiles
requires large inoculum to produce infection
direct invasion of mucosa cause exudative diarrhea
SSX- watery diarrhea more common, bloody may occur, h/a, malaise, N/V, abd pain 6-48 hr after ingestion, may have fever
course: usu self-limited to 7 days
Campylobacter jejuni and fetus (a mucosal invasion, a cause of bact gastroenteritis)
most common bacterial cause of bloody diarrhea in US
from contaminated pork, lamb, beef, milk products, water, infected pets
incubation period 1-7 days
SSX: may be prodrome of h/a, malaise for 12-24 hrs (resembles flu), then severe abd pain, high fever, profuse watery diarrhea, then bloody diarrhea
course: usu self limited to 7-10 days
Shigella (a mucosal invasion, a cause of bact gastroenteritis)
most common in children 6 mos- 5 yrs
food, water, milk can be contaminated; person to person
highly contagious with very small inoculum
SSX: incubation 1-3 days
in most people starts as lower abdominal pain, diarrhea, fever in 50%, many pt have biphasic illness starting as fever, abd pain, diarrhea; then in 3-5 days rectal burning, tenesmus, small volume bloody diarrhea
course: variable - children- resolves in 1-3 days, adults- resolves in 1-7 days
Enterohemorrhagic E. coli (a mucosal invasion, a cause of bact gastroenteritis)
E. coli 0157:H7 strain, produces the Shiga toxin, bovine reservoir, follows ingestion of undercooked beef or unpasteurized milk, fecal-oral, esp toddlers in diapers (daycare), often affects several ppl, ask if anyone else sick
SSX: acute onset of severe abd cramps, watery diarrhea > 16 hr after ingestion, becoming bloody within 24 hrs
course: lasts 1- 8 days if uncomplicated
5% are complicated by: hemolytic-uremic syndrome (HUS) - hemolytic anemia, thrombocytopenia, acute renal failure
thrombotic thrombocytopenic purpura (TTP) - HUS, fever, neurological deficits
Yersinia enterocolitica (a mucosal invasion, a cause of bact gastroenteritis)
Undercooked pork, unpasteurized milk, contaminated water
SSX: watery or bloody diarrhea and fever. May mimic appendicitis (RLQ pain, fever, vomiting, leukocytosis) if infection in terminal ileum. AKA “acute ileitis”
Note: Traveler’s Diarrhea (Turista)
Gastroenteritis caused by contact with organism endemic to locale visited (contaminated water or food ingestion)
Enterotoxigenic E coli is most common organism, also norovirus
SSX: nausea, vomiting, borborygmi, abd pain/cramps, diarrhea—onset 12-72 hr after ingestion.
Usually self-limiting, fever and bloody diarrhea suggest more serious disease
Cause of parasitic infections
Giardia lamblia
Cryptosporidium parvum
Entamoeba histolytica