Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Infectious Disease 2 > Diarrhea > Flashcards

Diarrhea Flashcards

1
Q

Definition of diarrhea

A
  • stool volume >200 g/d
  • loose to watery
  • abnormally frequent diarrhea (hard to measure)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Types of diarrhea to r/o

A
  • IBS: sensation of incomplete evacuation
  • Fecal incontinence
  • Overflow diarrhea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Daily fluids

A
  • 2 L ingested
  • 7 L digestive secretions
  • 8 L absorbed in small intestine
  • 500 mL absorbed in colon (can do slightly more if needed)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Osmotic gap in stool

A
  • if there is a gap, indicates presence of abnormal solute in stool
  • Osmotic diarrhea has gap >100 (lots of solute)
  • Secretory diarrhea has gap <50: no abnormal solute in stool
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Types of diarrhea

A
  • Inflammatory or non-inflammatory

Non-inflammatory

  • Secretory
  • persistent

Inflammatory

  • dt invasion
  • hemorrhagic dt cytotoxin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Clinical features of osmotic diarrhea

A
  • > 100 osmotic gap: lots of solute
  • contains water and mal absorbed solutes (lactose, fat, etc.)
  • resolves with fasting or cessation of offending agent
  • Ex. lactose intolerance, miralax, etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Clinical features of secretory diarrhea

A
  • <100 osmotic gap (no abnl solutes)
  • lots of water, lots of electrolytes
  • large volume of watery stool
  • ex. cholera
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Red flags for infectious diarrhea

A
  • high fever (>39C/102.2F)
  • systemic illness
  • Hematochezia
  • > 2 weeks
  • volume depletion
  • weight loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What percent of acute diarrhea is infectious?

A

90%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Three important topics to cover during history

A
  1. Is IV fluid replacement needed: volume depletion, vitals
  2. Is it osmotic or secretory
  3. Is it inflammatory or non-inflammatory: is there hematochezia (inflammatory)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the best way to determine if viral, bacterial, parasite?

A

good history

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Complications of infectious diarrhea

A
  • dehydration, hypovolemia
  • electrolyte loss (Na, K, Mg, Cl)
    Hypokalemia: dysrrhythmias
    Hypomg: tetany, tremor
    Metabolic acidosis: bicarb loss
  • vascular collapse: severe diarrhea, extremes of age
  • Acute tubular necrosis: renal failure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Infectious Diarrhea

- worldwide epidemiology

A
  • leading cause of childhood mortality
  • 5 million deaths a year
  • 2,195 deaths a day
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Infectious Diarrhea

- US epidemiology

A
  • 99 million acute cases a year
  • 5,000 deaths annually dt food borne illness
  • 95% of diarrhea deaths are people >65 yo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Infectious Diarrhea

- US risk factors

A
  • Immunocompromised
  • Institutionalized: SNF, prison
  • Social/occupational: day care
  • Travel: underdeveloped tropical regions (40%)
  • Food/Diet: raw meat, raw egg, shellfish, unpasteurized milk, buffets, picnic, poor food hygiene
  • *poop sprouts and poop spinach
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the pathway for infectious diarrhea?

A

fecal to oral, always. And yes that is disgusting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Risk factors of fecal-oral transmission (6)

A
  • improper disposal of feces, poor sanitation
  • drinking contaminated water
  • poor hand hygiene (esp. food handlers)
  • improper food hygiene
  • inadequate food refrigeration
  • food exposure to flies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Three common viral pathogens

A
    • Virus MC cause in US
  • rotavirus
  • norovirus
  • adenovirus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

7 common bacterial pathogens

A
  • E. coli
  • Salmonella
  • Shigella
  • Vibrio cholera
  • Yersinia
  • Campylobacter
  • C. difficile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

3 common parasitic pathogens

A
  • giardia
  • cryptosporidium
  • entamoeba hystolytica
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Two main ways pathogens cause diarrhea

A
  • inflammation

- active secretion (creates osmotic difference)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Inflammatory diarrhea

- pathophys overview: list the two mechanisms

A
  1. Direct invasion

2. Cytotoxin release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Inflammatory diarrhea

  • pathophys of direct invasion
  • common pathogens
A
  • invade gut lining, destroy macrophages as they try to engulf the pathogen
  • Salmonella typhi, Yersinia, Campylobacter, Norovirus, Rotavirus, Entamoeba histolytica
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Inflammatory diarrhea

  • pathophys cytotoxin release
  • common pathogens
A
  • directly cause cell death
  • C. diff
  • Shiga toxin producing orgs: shigella, STEC E. coli (STEC = shiga toxin producing e. coli)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is special about Shigella's MOA
invasive AND produces cytotoxins
26
Two main ways pathogens cause active secretion
1. Enterotoxin production | 2. Preformed toxins
27
Secretory Diarrhea - Enterotoxin production: pathophys - example of pathogen
- cause cells to secrete chloride into the lumen - Na and water follow - ex cholera
28
Secretory Diarrhea - preformed toxins: pathophys - example of 2 pathogens
- neurotoxins cause the secretin of water and electrolytes | - C. pefringes and staph aureus
29
Three types of toxins that make pathogens pathogenic
1. Enterotoxins 2. Cytotoxins 3. Neurotoxins
30
Enterotoxins - how produced - effect - example
- produced by pathogen inside the body - Act direction on mucosa to alter secretory mechanisms - Increase Cl secretion and inhibit Na resorption ex. cholera
31
Cytotoxins - production - effect - examples
- Produced by bacteria in body - destroy mucosal sells (direct destruction) - cause inflammation and dysentery - ex. shigella, STEC, c. diff
32
Neurotoxins - production - effect
- preformed toxins - produced outside the body - act directly on nervous system to alter secretion of electrolytes
33
Preformed toxins - vomiting - pain - fever - diarrhea - ex
- common - 1-2+ - rare - 3-4+ watery - staph, B. cereus, C. perfrigens
34
Enterotoxin - vomiting - pain - fever - diarrhea - ex
- common - ? - rare - 3-4+ watery - vibrio cholerae
35
C. diff cytotoxin - vomiting - pain - fever - diarrhea - ex
- rare - 3-4+ - rare - 2-3+ watery - C. diff
36
Shiga-toxins - vomiting - pain - fever - diarrhea - ex
- rare - 3-4+ - common - 1-2+ bloody - Shigella, E. coli (STEC)
37
Direct invasion: bacteria - vomiting - pain - fever - diarrhea - ex
- rare - 2-4+ - common - 1-4+ can be bloody - salmonella, Campylobacter, yersinia
38
Direct invasion: virus - vomiting - pain - fever - diarrhea - ex
- maybe - 2-3+ - common - 1-3+ watery - norovirus, rotavirus
39
Types of non-inflammatory diarrhea
* * pathogen attaches superficially, produces enterotoxin - Gastroenteritis: - Viral: norovirus, rotavirus, adenovirus - Bacterial: Staph. aureus (MC), clostridium perfringens, Bacillus cereus
40
Gastroenteritis - overview - sx
- affects stomach and small bowel - Caused by virus or preformed bacterial toxins - Nausea and vomitting - abd pain common
41
How to differentiate viral vs. bacterial gastroenteritis
- Bacterial: <10 hr incubation, no fever, 24 hour duration | - Viral: >14 hr incubation, mild fever, 72 hour duration
42
Viral gastroenteritis - overview - 3 main types
- "stomach flu" - Think daycare, school, cruise ship, sports teams - Norovirus (60-80%), all year, all ages - Rotavirus: <2 YO - Adenovirus: assoc. URI sx
43
Norovirus - overview - sx - timing - transmission
- MC cause GE - winter - very contagious - can survive for a long time on surfaces!! - Self limiting - n/v/d, crampy pain, low grade fever, +/- HA - lasts 1-4 days - transmission: fecal-oral via fomites, food, water (possible person to person or airborne droplets)
44
Bacterial GE - cause of sx - sx
- "food poisoning" - cause: preformed toxins (neuro toxins act on CNS) - rapid onset, short duration - vomiting
45
Bacterial GE | - three orgs
1. S. aureus: MC 2. Clostridium perfringens: meat, gravy, buffet 3. Bacillus cereus: "fried rice syndrome" from re-heating fried rice
46
Bacterial GE caused by S. aureus
- Very common - milk, meat, custard - preformed neurotoxin > CNS > vomiting - onset 2-8 hrs - lasts 3-6 hrs - 24 hour "stomach bug"
47
Secretory Diarrhea | - overview
- non-inflammatory - voluminous emts watery diarrhea - NO blood - NO high fever (usu) - active electrolyte secretion, no excess solute: low osmotic gap - diarrhea despite fasting - dehydration is worry
48
Secretory diarrhea | - examples
- Travelers diarrhea | - Vibrio cholerae
49
Traveler's Diarrhea | - 3 MC orgs
* * usually e. coli of some type - Enterotoxigenic E. coli - Enteroaggregative E. coli - Campylobacter jejuni
50
Traveler's Diarrhea - sx - pathogenesis - transmission
aka Montezuma's revenge - self limited, watery diarrhea, starts ~3 days after exposure, lasts 3-4 days - causes secretion of Cl - contaminated food/water in underdeveloped countries in tropical climates
51
Travelers Diarrhea | - tx
- oral fluids and electrolytes - pepto-bismol: sx control (black stool) - Imodium: sx control - Abx unnecessary!!!
52
Travelers Diarrhea | - prevention
- wash hands - bottled water - be a boring eater :) - ice/raw foods
53
Vibrio Cholerae | - overview
- rare in US, common in world - rapid spread, outbreaks - HIGHLY contagious - contaminated food or water* - poor sanitation - rainy season - 10% develop severe dz - death dt hypovolemic shock
54
Vibrio Cholerae | - pathophys
- Secretogogue: directly activates adenylate cyclase which opens Cl channels and causes massive secretion of Cl ion into gut lumen - Also increase cAMP in cells which stimulates water and Na secretion
55
Vibrio Cholerae | - trasmission
contaminated water MC
56
Vibrio Cholerae | - sx
* *Secretory diarrhea - large volume, watery (up to 1 L / hour) - "rice water stool" - vomiting common - reduced urine - rapid dehydration - muscle cramps - thirst - fever rare
57
Vibrio Cholerae | - Tx
- Oral rehydration #1 - Glucose containing solutions (ORS) given orally is best option - Forces sodium-glucose cotransporter in small intestine to transport glucose and sodium into enterocytes, Cl and water follow - IV fluids if severe: Ringers lactate - Abx if hospitalized - Zinc has been shown to shorten illness in children
58
Vibrio Cholerae | - vaccine
- 10 days prior to travel - 18-64 yo - 1 dose - Vaxchora or PaxVax - Risk of getting dz is higher if visit friends/relatives
59
Inflammatory Diarrhea - aka - basic pathophys - basic sx
- dysentery, infectious colitis - invades colon wall - bloody diarrhea, fever >101F, abd pain
60
Inflammatory Diarrhea | - pathogens
Many, she said to focus on: - Shigella - E. coli (STECs) - Salmonella (incld. tyhoid fever) - Campylobacter jejuni - C. diff
61
Shigella - describe org - MC species - overview
- gram neg bacillus - Four species cause diarrhea dz, Shigella sonnei is MC in US - not seasonal - VERY contagious, small infective dose - daycare breakouts - MC in children, families vulnerable
62
Shigella | - Sx
- 1-2 days after exposure - watery and/or bloody diarrhea - small volume of stool - tenesmus - abd pain - fever - 5-7 day course
63
Shigella | - Dx
stool tests: - WBC + - guiac + - culture +
64
Shigella | - Tx
* severe dehydration rare, supportive care only - fluid replacement, rest, bland diet - pepto-bismol - Abx only in severe cases
65
Escherichia coli - org description - org habitat
- gram negative motile bacillus - some produce shiga toxins = inflammation - part of normal flora in people and animals, few strains are pathogenic
66
E. coli - transmission - what do stool cultures detect?
- contaminated food/water - person to person - contact with animals - cultures only detect pathogenic strains
67
Two pathogenic strains of E. coli
1. Enteroinvasic E. coli: invasive, causes dysentery similar to shigellosis 2. Enterohemorrhagic E. coli: produces shiga toxin which causes colitis
68
Enterohemorrhagic E. Coli - aka - sx - how common - reservoirs and vectors
- E. coli 0157:H7 - "hemorrhagic" bloody diarrhea - can cause hemolytic-uremic syndrome ** - most common STEC in US - reservoirs: cattle, sheep, goats - vectors: birds, flies
69
Enterohemorrhagic E. Coli - Transmission - outbreaks
- contaminated food/water, contact with animals/feces/soil - food outbreaks: undercooked meat, vegetables irrigated with contaminated water (sprouts, spinach, lettuce) - can survive >9 mo in ground beef stored -20C
70
Enterohemorrhagic E. Coli | - Sx
- 3-4 days after exposure - starts watery, then bloody diarrhea - hemorrhagic colitis: severe abd pain, bloody stool, might present like UC
71
Hemolytic-uremic syndrome
* HUS - acute renal failure - hemolytic anemia - thrombocytopenia - 1 week after diarrhea stops, when pt is improving - 50% will require dialysis
72
Enterohemorrhagic E. Coli | - lab testing
- stool culture for STECs: detects shiga toxins or genes that encode them - report to state health dept
73
Enterohemorrhagic E. Coli | - tx
- supportive, fluid rehydration, bland diet - NO ABX (and stop them if they have been started): do not prevent complications/shedding DO increase risk of HUS and toxin release! - avoid anti-diarrheal like Lomotil
74
Salmonella - org - epidemiology and risks
- gram neg motile bacillus - 1.2M US annual cases - MC in summer - Children <5 highest risk - acid-lowering meds increase risk - handling of ducklings, reptiles, chicks, hedgehogs
75
Salmonella | - sx
- 12-72 hrs after exposure - diarrhea +/- blood, cramping, fever - children highest risk for dehydration
76
Salmonella | - tx
- supportive: rest, fluids and electrolytes - abx only if severe * bacteria shed in stool 4-5 weeks after illness!!
77
Typhoid fever | - sx
* severe illness caused by salmonella typhi | - sustained fever (103-104), chills, diarrhea (constipation too), cramping, HA, anorexia, cough, myalgia
78
Typhoid fever - transmission - incubation
- US pts usually get during travel outside the country - chronic carrier state can occur - incubation: 6-30 days
79
Typhoid fever | - tx
- abx - no tx: 30% die - vaccination avail if plan to travel to SE Asia
80
Campylobacter jejuni
- gram neg motile rod - flagellated - illness similar to salmonellosis - Foodborne and travel - undercooked poultry, meats, dairy, water - causes dysentery, also mild travelers diarrhea - late complication: Guillain-Barre syndrome (rare)
81
C. Diff - org -
- gram positive bacillus - spore-forming - normal inhabitant of colon - Secretes enterotoxin (A) and cytotoxin (B) - Abx associated colitis
82
C. diff | - sx
- 5-10 days after abx - diarrhea +/- blood - cramping pain - pseudomembranous colitis
83
C. diff | - lab test
stool assay for c. diff toxin
84
C. diff | - tx
- oral or enema vanc | - fecal transplant
85
Listeria - organism - transmission
- listeria moncytogenes - gram positive bacillus - food borne, can cause outbreaks - unpasteurized dairy products and lunch meat
86
Listeria | - who is at high risk
- immunocompromised | - pregnant women (13X risk)
87
Listeria | - sx
- fever and flu like sx - diarrhea less common - can cause sepsis - encephalitis/meningitis
88
Listeria - Dx - Tx
- blood culture | - abx
89
Yersinia - org - transmission
- Yersinia enterocolitica - gram neg bacillus - raw, undercooked, contaminated pork - Children>adults - MC in winter
90
Yersinia | - sx
- fever - diarrhea +/- blood - severe abd pain, common in RLQ - mimics appendicitis! - arthritis and erythema nodosum
91
Yersinia - Dx - Tx
- special culture to isolate (add request to lab order) | - Abx
92
Invasive amebiasis - org - transmission
- entamoeba histolytica - food or water, in US usually institutionalized, migrant laborers, Indian reservations - only 10-20% symptomatic
93
Invasive amebiasis | - sx
- Mild, intermittent diarrhea - urgency - +/- generalized pain/cramping - liver abscess (rare)
94
Amebic dysentery
- severe form of invasive amebiasis | - pain, bloody stool, fever
95
Persistent Diarrhea - define - common causes
- >14 days - Protozoa: guardia, cryptosporidium - insidious onset, intermittent sx - non-invasive (no inflammation or cell death), attach superficially to lining - common signs: weight loss, malabsorption
96
Persistent diarrhea | - w/u
- full GI w/u | - test for IBD, celiac, IBS, etc
97
Giardiasis - org - describe org - transmission
- Giardia lamblia - lives in intestines, passes in feces - Cysts can survive for months in cold water - transmission: contaminated water (mountain stream, camping) - MC intestinal parasite in US
98
Giardiasis | - Sx
- diarrhea - gas/bloat - greasy, foul smelling stools - cramps - upset stomach - n/v - intermittent, can be chronic - weight loss, malabsorption, lactose intolerance, vitamin A, B12 can occur
99
Giardiasis | - dx
- Microscopic stool examination (stool for O and P) | - stool antigen test
100
Giardiasis | - tx
Flagyl
101
Cryptosporidium - pathogen - epidemiology
- cryptosporidium parvum and C. hominis - protozoa - large waterborne outbreaks - contaminated water, resistant to chlorine - only small # oocysts needed for infection
102
Cryptosporidium | - sx
- abrupt, profuse, watery diarrhea - abd cramp - +/- nausea and anorexia - persists 1-2 weeks, then abates - asx shedding of oocysts continues for weeks
103
Cryptosporidium | - dx
- stool antigen test | - microscopic examination of stool (stool for O&P)
104
Cryptosporidium | - Tx
- abx - usually self-limited in immunocompetent people - can be severe in AIDS
105
Blastocystis hominis | - organism
- unclear classification historically - genus: Stramenopiles (protists) - common, found throughout world
106
Blastocystis hominis - transmission - sx
- contaminated water - diarrhea - gas - abd cramps - anal itching ** - weight loss - poss constipation - many people asx
107
Blastocystis hominis | - tx
abx
108
Clinical skills
see presentation for all the details
109
Diarrhea | - how to differentiate small colon from large
- Small: watery, high volume stool, signs of malabsorption, dehydration - Large: frequent, small volume stool, blood, urgency, tenesmus
110
Signs infection due to S. aureus or B. cereus
"food poisoning" - vomiting - 6 hrs after food - no/low fever
111
Signs infection viral
- incubation >14 hours | - HA
112
Signs invasive or toxin producing
- severe abd pain - high fever - peritoneal signs
113
Mild dehydration - alterness - vitals - s/sx - weight loss
- normal - no change - thirst - <5%
114
moderate dehydration - alterness - vitals - s/sx - weight loss
- restless, irritable, weak - tachycardia, postural hypotension - thirsty, dry membranes, poor skin turgor, dark urine - 5-10%
115
Severe dehydration - alterness - vitals - s/sx - weight loss
- unconscious, lethargy, floppy, unable to drink - weak/absent pulse, low blood pressure - sunken eyes, depressed fontanels, wrinkled skin, minima/no urine - >10%
116
S/sx indicate need to start a w/u
- high fever >101 or toxic appearing - severe sx, >6 diarrheas a day - severe dehydration - Evidence of colitis: bloody stool, severe abd pain - empiric tx failed - duration >2 weeks
117
Lab w/u for diarrhea
- fecal leukocytes: positive is inflammatory - Stool for ova and parasites: multiple samples best dt intermittent shedding - Stool culture: good for acute sx, helps narrow differential - CBC: anemia, leukocytosis, thrombocytopenia (HUS) - BMP: electrolytes, hyponatremia, metabolic acidosis (secretory diarrhea)
118
What orgs are on stool culture
- Salmonella - Shigella - Campylobacter - C. diff - E. coli (STEC) - +/- vibrio - +/- Yersinia
119
Diarrhea supportive care
- oral rehydration: pedialyte, sports drinks, make your own - IV fluids if can't quit vomiting or VERY volume depleted - anti-diarrheal: imodium, pepto-bismol - anti-emetics - BRAT diet, avoid dairy
120
When to use Abx
only when needed!! - severe - hospitalized - infants - elderly
121
Late complications of diarrhea
- Reiter's syndrome: reactive arthritis, urethritis, conjunctivitis - HUS (shigella, EHEC) - Autoimmune type sequelae: pericarditis, thyroiditis, glomerulonephritis - Post-infectious IBS
122
Exposure/condition vs. pathogen
great chart at end of lecture

Infectious Disease 2 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions