80. Gastroenteritis Flashcards
1
Q
Diarrhea defn
A
passage of 3 or more unformed stools per day, more than 250g/day or stool taking on form of container is its placed
2
Q
Dysentery defn
A
inflamm of intestine typically causing blood and mucus - generally assooc with fever, abdo pain, rectal tenesmus
3
Q
Gastroenteritis: what 2 infections typically cause diarrhea related death?
A
cdiff
norovirus
4
Q
Diarrheal illness classification - acute vs prolonged vs persistent vs chronic
A
acute (<7 days), pro- longed (7 to 13 days), persistent (14 to 29 days), or chronic (>30 days). Acute and prolonged gastroenteritis (13 or fewer days)
5
Q
Pathophysiology of gastroenteritis: 4 mechanisms:
A
- ingestion of preformed toxin
- adherence of infectious pathogen to intestinal cell walls
- invasion of mucosal wall
- production of enterotoxins and cytotoxins
6
Q
GI sx after short period - bug?
A
1-6h
staph or bacillus
7
Q
Diarrhea lasting more than 2 weeks - bug?
A
giardia
8
Q
Traveller’s diarrhea cause
A
enterotoxigenic e choli
9
Q
Travel to southeast asia - risk of diarrhea from what 2 bugs?
A
vibrio
campy
10
Q
South America, Asia, Africa travel diarrhea - bug?
A
rotavirus
11
Q
3 bugs/protozoa can get from recent camping
A
giardia
aeromonas
crypto
12
Q
Recent abx - diarrhea - worry?
A
cdiff
13
Q
Daycare exposure - 2 bugs risk?
A
rotavirus
noro
14
Q
Exposure to raw seafood - worry which bug?
A
noncholera vibrio
15
Q
Anal sex 4 possible bugs causing diarrhea?
A
shigella
campy
salmonella
entamoeba
16
Q
HIV diarrhea causing bugs -4
A
MAC
microsporidia
CMV
giardia
salmonella
cdiff
shigella
17
Q
Diarrhea outbreak on cruise ship bug?
A
norovirus
18
Q
Diarrhea outbreak contaminated local water, food etc: bugs?
A
campy
salmonella
ecoli
19
Q
Which bugs more commonly cause bloody diarrhea?
A
campy
shigella
20
Q
What bug causing diarhea mimics appendicits?
A
yersinia
21
Q
DDX gastroenteritis
A
SBO, diverticulitis, IBD, ischemic bowel disease, appendicitis, pancreatitis, hepatobiliary pathology, malabsorption, celiac disease, or irritable bowel syndrome.
22
Q
Stool cultures for Salmonella, Shigella, Campylobacter, Yersinia, Shiga toxin–producing Escherichia coli (STEC), and C. diffi- cile may be considered for patients with what features?
A
severe illnes
fever >38.5
dysentery
immunocomprised state
recent hospital
recent abx
23
Q
Shigella, salmonella typhi, vibrio noncholera - dx, tx
A
stool culture
ciprofloxacin 500mg PO BID x3d or azithro 500mg PO d for 3d
24
Q
Salmonella enteritids - dx, regular vs severe tx
A
stool, PCR
no tx vs sev: fever, bloody diarrh, bacteremia - levo 500mg IV or PO 7-10d
25
Campylobacter jejuni dx, tx
stool culture
azithro 500mg PO d for 3d, or erythromycin 500mg PO BID x5d
26
Vibrio cholerae dx and tx
dx stool culture with salt containing media
doxy PO 4-6mg/kg up to 300mg once daily for 3d
27
ETEC dx tx
stool culture and assay for toxin
ciprofloxacin 750mg Po x1 or 500mg PO bid x3d,rifaxamin 200mg PO TID x3d, azithromycin 1g PO once daily
28
Ecoli O157:H7 - dx, tx
sorbitol maconckey and serotype
NONE - supportive, risk HUS with abx
29
Yersinia: dx, tx
cIN agar
supportive, if sev: septra 1 tab PO BID x3d, ciproflocacin500mg PO BID x3d
30
Cdiff dx and tx
stool for cdiff toxin, PCR
vanco 125mg PO qid for 10d or fidaxocicin 200mg PO bid x10d
alt flagyl 500mg PO TID for 10d
31
Staph aureus as diarrhea cause: dx, tx
food may be cucltured but not routine
supportvie
32
Bacilus cereus: severe case tx
vancomycin 125 mg PO qid; or clindamycin 500 mg PO tid for 7–10 days
33
Giardia tx options
Tinidazole 2 g PO single dose
Metronidazole 500 mg PO bid or 250 mg tid for 5–7 days Nitazoxanide 500 mg PO bid for 3 days
Alternative agents
Albendazole 400 mg PO once daily for 5 days Mebendazole 200 mg PO tid for 5 days
Quinacrine 100 mg PO tid for 5 days
Paromomycin 10 mg/kg PO tid day for 5–10 days
34
Entamoeba histolytica: tx
Metronidazole 500–750 mg PO tid for 7–10 days; Tinidazole 2 g PO once a day for 3–5 days; Nitazoxanide 500 mg PO bid for 3 days Intraluminal infection
Paromomycin 25–35 mg/kg PO divided tid for 7 days. Iodoquinol 650 mg PO tid for 20 days for adults Diloxanide furoate 500 mg PO tid for 10 days for adults
35
Cryptosporidium tx
Nitazoxanide 500 mg PO bid for 3 days
36
Cyclospora cayetanensis: tx
Trimethoprim-sulfamethoxazole (TMP-SMX), one double-strength 160/800 mg tablet PO bid for 7–10 days
37
3 main types of ORT per WHO: what do these contain?
ORS (331 mOsm/kg), reduced osmolarity WHO ORS (245 mOsm/kg), and Pedialyte (oral electrolyte solution for children; 250 mOsm/kg).
Simple home remedies, such as diluted fruit drinks and chicken broth, or com- mercial solutions such as Gatorade will also suffice
38
Initial dose of loperamide and dosing
initial dose of loperamide is 4 mg PO, followed by 2 mg after each unformed stool, up to a maximum of 16 mg/day for 48 hours
NOT for children <18y
39
Invasive vs noninvasive bacterial gastroenteritis:
Invasive gastroenteritis is a clinical diagnosis made in the presence of signs or symptoms of intestinal mucosal invasion, such as fever, gross or occult blood in the stool, tenesmus (feeling of con- stantly needing to pass stool), or severe abdominal pain
Patients with noninvasive gastroenteritis generally do not exhibit fever, produce bloody stools, or experience significant abdominal pain. Noninvasive gastroenteritis likely suggests the presence of a viral pathogen or toxin-producing bacteria.
40
Campylobacter clinical features
Most common bacteria; organism identified in stool cultures; acute watery diarrhea, fevers, dysenteric characteristics
41
DDX of invasive bacterial gastroenteritis:
campy
salmonella nontyphoid and tyhpod
shigella
yersinia
vibrio noncholera
ecoli O157:H7
42
Bacteria: Usually foodborne (e.g., poultry); acute watery diarrhea, often with fever; common in sickle cell and immunocompromised patients
salmonella nontyhpod
within 12-24h, lasting 2-7d
43
Bacteria? Fever, abdominal pain, ileus, systemic effects; most infections acquired during international travel
salmonella typhoid
44
Bacteria? Common worldwide; acute watery diarrhea, fever, dysenteric characteristics; toxigenic; high incidence in men who have sex with men
shigella
45
Bacteria? Acute diarrhea, dehydration; rare in the United States but common with travel to Asia; can mimic appendicitis
Yesinia
46
Bacteria? Associated with seafood, shellfish; watery diarrhea, dysentery
vibrio
47
Bacteria? Watery, bloody diarrhea; foodborne—contaminated beef or produce; toxigenic; associated with HUS
and TTP
ecoli O157:H7
48
DDX noninvasive toxigenic bacterial gastroenteritis
staph aureus
clostridium perfringens
bacillus cereus
vibrio cholerae
marine bacteria like scombroid
noncholera vibrio
Cigatera fish poisoning
ETEC
Cdiff
49
Bacteria? Short incubation period, 2–7 h; preformed toxin; vomiting; lasts <24 h
staph aureus
50
Bacteria: 6-24h, Watery diarrhea, seen in large foodborne outbreaks
clostridium perfringens
51
Bacteria? Vomiting or diarrhea, typically from contaminated rice
bacillus cereus
52
Bacteria?
Enterotoxin; acute “rice water” diarrhea, dehydrating. Rare in the United States but common with travel to Asia
53
Bacteria? Enterotoxin. Acute diarrhea, occasional dysentery. Seen in Gulf coast in the United States. Can cause septic shock, wound infection
noncholera vibrio
54
Scombroid presenting sx
histamine toxin
tachycardia
itching
flushing
cramping dizziness
meetaollic taste
within 5-60min **mahi mahi, tuna other dark meat
55
Ciguatera fish - toxin sx?
pain, paresthesia, dyesthesia, vomiting, diarrhea
within 2-6h
coral reef fish
56
Bacteria? Acute watery diarrhea. Common cause of traveler’s diarrhea, but in the United States increasing cause of foodborne disease
etec
57
Recent PPI - bacteria?
cdiff
58
Salmonella - when to use abx? what RF
severe colitis and infants younger than 3 months, adults older than 50 years, and those at risk for severe disease, including those who are immunocompromised, with sickle cell disease, or with prosthetic grafts.
59
Salmonella prevention?
cooking meat internal greater than 160°F (71°C) and minimizing how long foods are allowed to remain at room temperature,
60
Post infection complications of Yersinia
erythema nodosum, persistent polyarthritis, sacroiliitis, ankylosing spondylitis, Reiter syndrome, exudative pharyngitis, pneumonia, empyema, or lung abscess.
61
How does Vibrio produce effect?
two thermostable direct hemolysin virulence factors - attach to colonic epithelium inducing secretory diarrhea, local cell lysis
62
What temp allows staph aureus allow for proliferation of organism
Temperatures of 45°F to 140°F (7°C to 60°C) for only a few hours will allow the proliferation of the organism and production of sufficient enterotoxin to cause disease.
63
How do Cholera and noncholera Vibrio strains work?
stimulate enterocyte adenylate cyclase, disrupting mucosal fluid absorption and leading to secretory diarrhea
64
Complications of cdiff
none
, pseudomembranous colitis, toxic megacolon, intestinal perforation, and death
65
Why are cdiff spores so hard to kill?
Difficile spores are highly resistant to heat, acid, and antibiotics, making them highly contagious for person-to-person or surface-to-person infections. C. difficile bacte- ria secrete toxins A and B that cause inflammation, mucosal injury, and secretory diarrhea.
66
Cdiff wbc level common?
>15
67
Virus? Most common cause of gastroenteritis in the United States, and most common cause of US foodborne-disease outbreaks; fever, headache, myalgias, nausea, vomiting, abdominal pain, diarrhea; incubation period, 12–48 h
norovirus
68
Virus? Fever, nausea, vomiting, diarrhea; usually causes mild illness
sapovirus
69
Virus: Fever, nausea, vomiting, abdominal pain and watery diarrhea; incubation period ≅ 2 days
rotavirus
70
Virus? Rare cause of serious illness; fever, diarrhea; can cause nongastrointestinal illness (e.g., bronchitis, pneumonia, conjunctivitis)
adneovirus
71
Virus? Malaise, headache, abdominal pain, diarrhea; vomiting less common
astorvirus
72
Parasite? Nausea, vomiting, abdominal cramping, flatulence, greasy stool that may float
giardia
73
Parasite? Fever, anorexia, abdominal cramping, watery or bloody diarrhea; illness ranges from asymptomatic infection to fulminant colitis, peritonitis to extraintestinal amebiasis
entaemoeba histolytica
74
Parasite? Abdominal cramping, diarrhea. One of the most frew causes of waterborne disease in US population
crystosporidium
75
Parasite? Nausea, vomiting, loss of appetite, weight loss, bloating, abdominal cramping, diarrhea
cyclospora
76
How does giardia work?
trophozoite (active form) and cyst (inactive form).
Trophozoites attach to the mucosal lining of the small intestine and cause symptoms.
This active form of the parasite is unable to survive outside the body for an extended period of time and hence cannot spread infection to others. However, the cystic form is viable outside of the body for prolonged periods and, once ingested, changes into the trophozoite form. Trophozoites generate the cysts that exit the body via the feces.
77
DDX food borne illnesses
staph
b cereus
scombroid
ciguaeteria fish poisoning
slight longer at 16h: etec, stec, shigella, vibrio
78
What fish cause scombroid?
Scombridae (e.g., tuna, mackerel, skipjack, bonito, and related species) but results from the ingestion of a wide variety of dark meat fish, including nonscombroid species such as herring, bluefish, anchovy, sardine, amberjack, black marlin, and mahi mahi.
79
Traveller's diarrhea: mild?
tolerable, not distressing, does not interfere with planned activities
no abx
80
Traveller's diarrhea: mod
distressing, interfers with activities
abx if immunosuppressed, solid organ transplant, elderly
81
Traveller's diarrhea: severe
Diarrhea that is incapacitating or prevents planned activities; all dysentery (passage of grossly bloody stools) is considered severe. Antibiotics are indicated for severe traveler’s diarrhea
82
Organisms causative of traveller's diarrhea?
ETEC
Enteroaggregate ecoli
campy
salmonella
shigella
noro
rotavirus
giardia
83
Indications for bismuth subsalicylate traveller's diarrhea
The antacid bismuth subsalicylate decreases the incidence of trav- eler’s diarrhea by 65% due to its antibacterial and antisecretory effects. The recommended dose is two tablets PO qid or one fluid ounce PO qid. Bismuth subsalicylate should be avoided in those who are allergic to aspirin because it contains salicylate. Potential side effects include blackening of the tongue or stool. It should not be taken for more than 3 weeks.
84
Traveller's diarrhea prevention options?
rifaximin 200mg PO d or bid duration of tx
or bismuth
85
After eating undercooked ground beef, a patient develops fever, abdominal pain, bloody diarrhea, and rectal tenesmus. Local health authorities are investigating a common source from a local diner, as 10 other patrons have presented with the same symptoms. Which of the following organism is likely to produce this dysentery outbreak? a. Giardia
b. Norovirus
c. Shigatoxin–producingEscherichiacoli(O157:H17) d. Staphylococcus aureus
c
86
A patient from a resource-rich country has traveled to a resource-
poor developing country. He develops diarrhea, up to four times a day, with yellow watery stools. There is no fever or abdominal pain. Which of the following organism is most commonly the etiology of Traveler’s Diarrhea?
a. EnterotoxigenicEscherichiacoli(ETEC) b. Giardia
c. Shigella
d. Vibrio noncholera
a
87
A patient comes to the emergency department (ED) with a com- plaint of abdominal cramping and vomiting twice; the first time was the food ingested from a buffet 8 hours ago and the second time yellowish vomitus. There is no diarrhea or fever. There is contin- ued retching intermittently in the ED. What is the likely causative organism?
a. Clostridium perfringens
b. Escherichia coli O157:H7—Shiga-producing toxin c. Norovirus
d. Salmonella enteritidus
a
88
A 5-year-old patient with a likely viral gastroenteritis for 3 days is determined to be dehydrated. What is optimum mode of rehydra- tion therapy in this patient?
a. High-glucose solution (e.g., apple juice)
b. IV normal saline (0.9%)
c. Oral hydration with clean water
d. Reduced osmolarity (245 mOsmol/kg) oral rehydration solution
d
89
A patient presents with non-bloody diarrhea for 5 days, crampy abdominal pain, and bloating. The white blood cell (WBC) is 16,000/mL. Which of the following types of patient and scenario is most likely to put the patient at high risk for Clostridium difficile? a. A 3-year-old toddler in daycare
b. Elderly nursing home patient
c. Nurse who works in the emergency department d. Traveler on vacation returning from Mexico
b
90
