2: Infectious Diarrhea Flashcards
describe normal stool volume
3-7 bowel movements/day
describe acute infectious diarrhea volume
20-30 bowel movements/day
up to 20L stool/day
diarrhea reflects increased water in stool from what two mechanisms
- increased intestinal secretion of water
2. decreased intestinal reabsorption of water
what three things must you differentiate diarrhea from?
- pseudodiarrhea
- fecal incontinence
- overflow incontinence
describe pseudodiarrhea
- rectal urgency
- related to anal infection
describe fecal incontinence
-sudden discharge involuntarily
describe overflow incontinence
-obstupation or chronic constipation, then overflow of liquid stool around the solid stool -> leaks out of rectum
duration of each of the following:
- acute diarrhea
- persistent diarrhea
- chronic diarrhea
acute: less than 14d
persistent: 14-30d
chronic: more than 30d
causes of acute diarrhea in healthy adults of developed countries
- usually viral
- more severe diarrhea more likely bacterial
- protozoa least common causes
is stool culture high yield?
nope - about 1-6% of patients showed positive stool cultures
S. aureus story
- incubation 1-6h
- major sx: vomit
- prepared food - salads, dairy, meat
- cream pie at picnic
B. cereus story
- incubation 1-6h
- major sx: vomit
- rice, meat
- leftover fried rice
Norwalk-like virus story
- incubation 24-48h
- major sx: vomit
- shellfish, prepared foods, salads, sandwiches, fruit
- cruise ships
non-typhoidal salmonella story
- incubation 1-3d
- major sx: inflammatory diarrhea
- eggs, poultry, meat, unpasteurized milk or juice, fresh produce
- hamburgers at picnic
shiga toxin-producing E. coli story
- incubation 1-8d
- major sx: inflammatory diarrhea
- ground beef, unpasteurized millk and juice, raw vegetables, water
- E. coli O157:H7 - hamburgers, spinach
v. parahemolyticus story
- incubation 2-48h
- major sx: inflammatory diarrhea
- raw shellfish
- sushi
v. vulnificus story
- cirrhosis/ decreased immune system pt eating raw oysters in redneck riviera
- months without an “r”
- starts as GI issues
review of C. perfringens
- enterotoxin produced by bacteria in small intestine
- acute gastroenteritis sx: acute watery diarrhea
- home-canned
-ingested bacteria can cause pig bel (necrotizing enteritis)
review of C botulinum
- paralytic neurotoxin formed by bacteria present in anaerobic environment
- weakness, diplopia, progresses to paralysis
- botulism
review of C tetani
- excitatory neurotoxin formed by bacteria present in wounds
- lockjaw
review of C difficile
- toxin mediated colitis caused by overgrowth of C diff in colon
- pseudomembranous colitis
norovirus story
- cruise ships
- schools
- nursing homes
- camps
- military barracks
- vegetables
- waterborne or foodborne
- shellfish-associated outbreaks
rotavirus story
- day care
- nurseries
- Australia
Hep A story
- MSM (men sex men)
- shellfish
- food workers
- overcrowding
- lack of clean water
- patients and staff of institutions
- day care centers
- IV drug users
- traverlers
- military barracks
- shellfish
Giardia lamblia story
- travel
- surface water drinking
- daycare centers
- swimming pools
- fruit salad
ETEC story
- traveler’s to developing world
- traveler’s diarrhea
C. diff story
- hospitalization
- inpatient or outpatient antibiotics or chemotherapy within the last several weeks
- daycare
- antibiotics!!!
V. cholerae
- acute, watery diarrhea (rice water stool), large volume
- no blood or pus in stool, no fever
- dehydration! - treat with ORT
history for patients complaining of diarrhea
- onset of abnormal bowel movements
- frequency in last 24h
- presence of blood, mucus
- do you have to get up in the night for bowel movements?(indicates more pathologic, osmotic cause)
- associated symptoms - skin/joint, fever, pain
- exposures - surface water drinking, camping, traveled
- any recent antibiotic use
bristol stool chart classifications
type 1: separate hard lumps, like nuts (hard to pass)
type 2: sausage-shaped but lumpy
type 3: like a sausage but with surface cracks
type 4: like a sausage or snake, smooth and soft
type 5: soft blobs with clear-cut edges
type 6: fluffy pieces with ragged edges, a mushy stool
type 7: watery, no solid pieces, entirely liquid
physical exam for patients complaining of diarrhea
- vital signs
- general
- abdominal exam - tenderness, evidence of surgical abdomen (need immediate surgery)
- musculoskeletal - arthritis comes with inflam bowel disease
- skin - associated rashes (watch for severe vasculitic rash)
- rectal exam
what are signs for surgical abdomen
- absence of bowel sounds
- diffuse, severely tender
- distended
- tympanitic
- rebound, guarding
- board-like rigidity
arthritis vs. arthralgia
arthritis - joints red, warm, swollen, tender, evidence of synovitis
arthralgias - just joint pain, no swelling or tenderness
what does a severe vasculitic rash look like?
non-blanching (like a bruise)
what are some anal pathologies that can be in differential?
- anal fissures - trauma, anal sex, constipation; usually not pathological; can cause hematochesia (bright red blood in stool), more benign
- hemorrhoids
- anal fistula - tend to be more severe issue, usually acquired from inflammatory bowel disease
- anorectal HPV (sometimes pt mistakes for hemorrhoids)
evaluation of acute diarrhea
study UpToDate chart in packet
role of testing in acute diarrhea
- routine stool culture
- ova/parasites
- endoscopy
indications for ova/parasite culture
-3 specimens on alternate days (3d)
- persistent diarrhea
- persistent diarrhea following travel to Russia, Nepal
indications for endoscopy
-persistent bloody diarrhea
treatment of acute diarrhea: 5 options
- ORT
- symptomatic therapy
- probiotics
- dietary alterations
- empiric antibiotics
describe ORT
-1/2 tsp salt
-1/2 tsp baking soda
-4 Tbsp sugar
per L of water
describe symptomatic therapy of acute diarrhea
anti-motility agents
- loperamide (imodium)
- diphenoxylate (lomotil)
bismuth subsalicylate (pepto-bismol)
*don’t give anti-motility to patients w/ C diff b/c can give them toxic megacolon
describe probiotics for acute diarrhea
- align
- culturelle
describe dietary alterations for acute diarrhea
- avoid dairy (temporary loss of lactase)
- low-residue diet (“white foods”, cooked vegetables, low fat meats)
BRAT diet
- bananas
- rice
- applesauce
- toast
describe empiric antibiotics for acute diarrhea
- fluoroquinolone (cipro 500 mg BID, levofloxacin 500 mg QD x 3-5d)
- metronidazole 500 mg TID x 7d
directed therapy guided by culture results (Sanford Guide helpful)
chronic diarrhea: secretory type of watery diarrhea
- reduced water absorption
- nocturnal
- persists despite fasting
- microscopic colitis
- stimulant laxatives (senna)
chronic diarrhea: osmotic type of watery diarrhea
-related to intake
- osmotic laxatives (miralax)
- Olestra (Wow!)
chronic diarrhea: functional type of watery diarrhea
- hypermotility
- improves with fasting
-irritable bowel syndrome
chronic diarrhea: malabsorptive/osmotic type of fatty diarrhea
- bloating
- gas
- steatorrhea
- giardiasis
- celiac disease
chronic diarrhea: maldigestive type of fatty diarrhea
-loss of digestive fxn (meat fibers)
- chronic pancreatitis
- cystic fibrosis
chronic diarrhea: IBD type of inflammatory diarrhea
- WBCs
- pus
- blood
- ulcerative colitis
- Crohn’s disease
chronic diarrhea: invasive type of inflammatory diarrhea
- infectious causes (pus)
- C diff
chronic diarrhea: neoplasia type of inflammatory diarrhea
- associated weight loss
- abdominal pain
-Colon carcinoma
which bugs cause diarrhea from the small bowel + what is the mechanism of each?
- Salmonella (dysentery - bloody)
- E. coli (dysentery - bloody)
- C. perfringens (preformed toxin - large volume, watery)
- S. aureus (preformed toxin - large volume, watery)
- B. cereus (preformed toxin - large volume, watery)
- V. cholerae (enterotoxin)
- Giardia lamblia (enteroadherent)
which bugs cause diarrhea from the colon + what is the mechanism of each?
- Campylobacter (dysentery - bloody)
- Shigella (dysentery - bloody)
- C. diff (cytotoxin - bloody, abdominal pain)
- E. coli O157:H7 (cytotoxin)
- E. histolytica (dysentery - bloody)
