Gastrointestinal Infections Flashcards
(163 cards)
1
Q
Define acute diarrhea? Likely etiology?
A
0-14 days
Viral or bacterial
2
Q
Define persistent diarrhea? Likely etiology?
A
14-29 days
Viral or bacterial in immunocompromised.
3
Q
Define chronic diarrhea? Likely etiology?
A
30 days or more
Parasites, noninfectious etiology should be excluded
4
Q
History to get in diarrhea patient [6]
A
- Travel
- Trips to pools, lakes, brackish or salt water
- Occupational history
- Abx use or healthcare exposure
- Animal contacts
- Prison or child care
5
Q
Red flag symptoms of gastroenteritis [10]
A
- Persistent stook >1 week
- Fever
- Bloody diarrhea
- Severe abdominal pain
- Weight loss
- Dehydration
- Recent abx use or hospital stay
- Pregnancy
- Age over 65
- DM or HIV patient.
6
Q
Who with diarrhea should get abx? [2]
A
- Immunosuppressed who are systemically unwell with fever or bloody diarrhea or abdominal pain
- Returning travelers with temp >38.5 and/or sepsis
7
Q
Who absolutely should NOT get abx? [2]
A
E. coli 0157
Shiga toxin producing organisms
8
Q
Duration of viral gastroenteritis based on etiology?
A
Noro: 2 days
Rota: 3-8 days
9
Q
Diagnosis of viral gastroenteritis
A
Mostly clinical with N/V/diarrhea
EIA for noro, adeno, rota virus available
PCR for viruses is also available
PCR is more sensitive and specific than EIA
10
Q
Treatment of viral gastroenteritis?
A
<65 a 1-2 day course of loperamide can be used
AVOID if bloody diarrhea or age >65 [risk of paralytic ileus]
11
Q
What type of virus is norovirus?
A
RNA
Calicivaradea
12
Q
Most common cause of gastroenteritis world wide?
A
Norovirus
13
Q
Incubation period of norovirus?
A
24-48 hours
14
Q
Lab abnormalities in norovirus?
A
WBC may be normal or elevated
Lymphopenia
15
Q
Infection control and prevention principles for norovirus
A
- Private room
- Wash hands with soap and water
- Exclude people from work for 48-72 hours after resolution of symptoms
16
Q
Most common causes of bacterial diarrhea in US? [7]
A
- Salmonella
- Camphy
- Shigella
- Shiga toxin producing E. coli
- Vibrio
- Yersinia
- Listeria
17
Q
Name the pathogenic forms of E. coli [5]
A
- Enterotoxigenic [ETEC]
- Enteropathogenic [EPEC this is mostly in kids <6 mos]
- Enterohemorrhagic [EHEC AKA Shig toxin producing E. coli AKA STEC]
- Enteroinvasive [EIEC]
- Enteroaggregative [EAEC]
18
Q
How does ETEC typically look?
A
Diarrhea in returning travelers with nausea but no vomiting.
Symptoms last ~5 days
19
Q
What toxins does ETEC make? [2]
A
Heat-stable
Heat-labile
20
Q
Presentation of EIEC?
A
Watery diarrhea that may progress to bloody
–> RARE.
21
Q
Presentation of EAEC?
A
Persistent diarrhea in immune compromised
22
Q
Two types of EHEC?
A
E. coli 0157:H7
E. coli O104:H4 [Shiga toxin producing]
23
Q
Presentation of EHEC?
A
- Bloody diarrhea
- Abdominal tenderness
- No fever
24
Q
EHEC complication
A
Pseudomembranous colitis
HUS 5-10 days after diarrhea
Intussusception
25
What type of culture should be done to diagnos EHEC?
MacConkey Sorbitol agar for O157:H7
26
Who gets HUS
Mostly those <10 years old
| Abx use increases risk of HUS 25%
27
Gram stain of camphy?
Gram negative S or spiral shaped
28
Animal exposure related to camphy?
Poultry and birds
29
Who do you get camphy?
```
Eating undercooked meat
Cross contamination of food from infected raw meat.
Swimming or drinking contaminated water
Person to person spread is rare.
Sexual transmission in MSM rarely
```
30
Risk factors for camphy infection?
Decreased stomach acid [achkirhydria]
| PPI use.
31
Camphy presenation
Incubation 3 days [mean 1-7]
Prodrome of fevers, rigors, dizziness prior to GI symptoms in 1/3
Watery or bloody diarrhea which is self limiting lasting 1 wk
N/V in 15-25%
Abrupt abd pain often periumbicical
Abd pain may mimic appendicitis and persist after diarrhea
32
Risk of campy bactermia
<1%
33
How long are patients after symptoms of camphy have resolved infectious?
Shed without symptoms for 38 days
| Relapse in 5-10% with recurrent infections and bacteremia
34
Camphy complications [3]
Guillain-Barre
Reactive arthritis
Colitis
35
Tx or reactive artheitis? [2]
1. Supportive
| 2. NSAIDs
36
GBS following camphy...
Occurs how often?
When does it occur?
Why does it occur?
Occurs in 3-40% of those infected
Occurs 1-2 weeks after infection
Due to formation of GM1 ganglioside antibody present in peripheral nerve myelin
37
How does miller fisher GBS look?
Ataxia, eye muscle weakness, areflexia but usually no limb weakness
38
How does post camphy colitis look
Effects ileum and jejunum
May go on to effect cecum and colon
May be part of pathogenesis of IBD
39
Diagnosis of GBS or reactive arthritis due to camphy?
- Stool cultures will be negative
| - Use serology, ELISA, or compliment fixation
40
Who with camphy diarrhea should get abx? [5]
1. Immunosuppressed
2. Elderly
3. Pregnant
4. Sever disease [fever + bloody diarrhea, symptoms >1 wk]
5. Relapsing symptoms
41
Treatment if abx is infected for camphy diarrhea? [2]
Azitho
Cipro Alt
3 days in normal host
1-2 weeks in severe disease or immunocompromised
42
Treatment for camphy bacteremia
Carbapenem + aminoglycoside
43
What are the two non-typhoidal salmonella?
1. Enteritidis
| 2. Typhimurium
44
What type of disease does non-typhoidal salmonella cause?
Inflammatory diarrhea
45
When does non-typhoidal salmonella peak?
Summer and fall
46
What types of exposure places one at risk for non-typhoidal salmonella?
1. Poultry
2. Eggs [Transovarial transmission from infected hens to intact egg shells].
3. Fresh Produce
4. Contaminated infant milk formula
47
Presentation of non-typhoidal salmonella
Incubation of 8-72 hours
Fever, diarrhea, abdominal pain, nausea, vomiting
Fever for 48-72 hours
Diarrhea for 4-7 days
48
How often does non-typhoidal salmonella develop bactermia?
<5%
49
Complications of non-typhoidal salmonella bactermia? [4]
1. Mycotic aneurysms
2. Abscesses
3. Osteomyelitis
4. Endocarditis
50
Diagnosis of non-typhoidal salmonella
1. Stool culture
| 2. Blood culture if persistent fever.
51
Treatment of non-typhoidal salmonella
Avoid abx in most due to risk of prolonged carriage
| Supportive
52
Who with non-typhoidal salmonella should get abx? [7]
1. Immunocompromised
2. HIV patients
3. Age >50 due to increased risk of endovascular infection
4. Stools >9-10 days
5. Persistent fever
6. Hospital admission
7. Cardiac or other valvular disease
53
Abx selection for non-typhoidal salmonella [4]
1. Azithro [preferred]
2. Cipro/Levo [only 0.4% resistance in USA]
3. 3rd gen cephalosporins [2.4% resistance for ceftriaxone]
4. Bactrim [alt]
54
Length of treatment for non-typhoidal salmonella [3]
3-7 for severe non-bactermic disease
3-14 if at risk for endovascular or joint complications
2-6 weeks if HIV
55
Which type of non-typhoidal salmonella is cleared quickly and has lower risk of carriage?
Typhimurium
56
Define chronic carriage with non-typhoidal salmonella
Continued shedding for over 1 year with repeated positive cultures.
57
Who tends to become chronic non-typhoidal salmonella carriers?
1. Women
2. Older adults
3. Young children
4. Biliary tract abnormalities such as gallstones
58
Treatment of non-typhoidal salmonella chronic carriage
Quinolones for 4-6 weeks
Amoxicillin for 6 weeks
Bactrim for 12 weeks
May need cholecystectomy
Follow up cultures 6 months after completed therapy
59
Etiology of enteric fever aka typhoid fever
1. Salmonella enterica serotype Typhi
| 2. Salmonella enterica serotype Paratyphi A, B, and C
60
Where does enteric/typhoid fever occur?
Asia and Africa most commonly.
61
Who gets enteric/typhoid fever [2]
1. Children
2. Adults
--> Elderly is less common.
62
Who becomes a chronic carrier in enteric/typhoid fever [2]
1. Women
| 2. Those with gallstones
63
What is chronic carriage in enteric/typhoid fever?
Sheds in stool and urine for >12 months following infection in 1-6% of patients.
64
Risk factors for shedding salmonella in the urine? [3]
1. BPH
2. Renal Stones
3. Concurrent schistosoma infection
65
Presentation of enteric/typhoid fever
Week 1: Fever >40 C with chills and rigors. Faget's sign. Diarrhea OR constipation.
Week 2: Abd pain with rose spots transiently
Week 3: Abd perforation secondary to necrosis and lymphatic hyperplasia of Peyer's patches. Hepatosplenomegaly, GI bleeding, septic shock, AMS.
Alternatively infection may resolve in a few weeks to months without abx.
66
Extraintestinal manifestations of enteric/typhoid fever?
1. HA
2. Typhoid encephalopathy
3. Bacterial seeding to hepatobiliary, respiratory, GU, MSK with cough and arthralgia
67
Lab findings in enteric/typhoid fever
1. Leukopenia
| 2. Anemia
68
What is Typhoid encephalopathy [5]
1. Altered sleep pattern
2. Psychosis
3. Upper motor neuron type disease
4. Ataxia
5. Parkinsonism
69
Diagnosis of enteric/typhoid fever [3]
1. Blood cultures [+40-80%]
2. Stool culture [+30-40%]
3. Bone marrow biopsy
70
Role of bone marrow biopsy in diagnosis of enteric/typhoid fever?
Yield >90% in complicated or unresponsive cases.
| Can remain positive even after abx therapy
71
Treatment of enteric/typhoid fever
1. Cipro in non-severe disease if no resistance suspected
2. Ceftriaxone for severe disease for 10-14 days
3. Azithro as alternative for 5 days
72
Treatment to eliminate carriage of enteric/typhoid fever
4 weeks of cipro
73
Microbiology of shigella
Nonmotile gram negative
Facultative anaerobe
3rd MMC of infectious diarrhea in USA
74
Pathophysiology of shigella infection? [3]
1. Invade mucosal cells causing abscess formation and mucosal ulceration
2. Spread from cell to cell
3. Produces enterotoxins
75
Describe the toxins of shigella
1. shET2 [plasmid, all species produce]
2. shET1 [chromosomal, produced by S. flexneri 2a]
3. Shiga toxin [chromosomal, produced by S. dysenteriae]
76
Which toxin is a/w HUS?
Shiga toxin
77
Presentation of shigella diarrhea?
Incubation for 3 days
Abd pain, watery diarrhea that proceeds to bloody in 35-55%
Self limited disease after 7 days
78
Complications of shigella? [4]
1. Bacteremia
2. HUS
3. Reactive arthritis
4. Leukemoid reaction
79
Who gets abx in shigella patients? [4]
1. HIV
2. Immunosuppressed
3. Bacteremia
4. Extraintestinal disease
80
Choice of abx in shigella?
1. Ceftriaxone if risk factors
| 2. Fluoquinolones if no risk factors
81
Length of treatment with shigella
Normal Host: 3 days
HIV: 5-7 days
S. dysenteriae infection: 5-7 days
82
What type of food puts you at risk for Yersinia enterocolitica infection? [3]
1. Unpasteurized milk
2. Undercooked pork
3. Pig fece contaminated water
83
Presentation of Yersinia enterocolitica?
1-14 day incubation
Pharyngitis seen in 20% of patients which is a distinguishing feature
RLQ pain
--> More prolonged illness, up to 22 days
84
Yersinia enterocolitica complications [7]
1. Abscess formation in the liver and spleen
2. Mesenteric adenitis [appendicitis mimic]
3. Terminal ileitis
4. Pseudoappendicitis
5. Reactive arthritis
6. Erythema nodosum
7. Cross reacts with antibodies in graves
85
Diagnosis of Yersinia enterocolitica?
1. Stool culture
| 2. Throat culture if pharyngitis
86
Treatment of Yersinia enterocolitica
1. Most just supportive care
2. Ceftriaxone or cipro if severe
3. Bactrim and cefotaxime also options
87
Food that leads to cholera?
Seafood
88
Presentation of cholera?
Incubation is only hours to days
Profuse watery diarrhea "rice water stool"
Abd discomfort, borborygmi, vomiting may occur early in disease course.
89
What is Plesiomonas Shigelloides?
Gram negative bacteria
| Due to ingestion of raw seafood
90
Treatment of Plesiomonas Shigelloides? [4]
1. Quinolones
2. Azithro
3. Augmentin
4. Ceftriaxone
3-5 days for GI illness
1-2 weeks for extraintestinal illness
Tx is NOT recommended in mild to moderate illness.
91
Food associated with listeria?
1. Unpasteurized milk
2. Soft cheeses or pate
3. Prepared salads containing tuna, chicken, or ham
4. Smoked seafood
92
Presentation of listeria
Mostly a self limited gastroenteritis
93
Describe the toxins of C. diff
Toxin A: Enterotoxin that causes inflammation with intestinal fluid secretion and damage to the mucosa.
Toxin B: Cytotoxin which is more potent than A.
94
What is the hypervirulent strain of C. diff?
NAP1/B1/027
95
Define non-severe C. diff
WBC <15 AND Cr <1.5
96
Define severe C. diff
WBC >15 OR Cr >1.5
97
What measurements on imaging is needed to diagnose toxic megacolon
Colonic diameter >7 cm
| Cecum >12 cm
98
What medication should be d/c in those with C. diff?
PPI
99
Food associated with C. perfringens gastroenteritis
Poorly stored meat and gravy.
100
What type of disease doe Type C C. perfringens produce?
Hemorrhagic necrosis of the jejunum through a Beta-toxin. This is called enteritis necroticans or pigbel disease
101
What increases risk of Enteritis necroticans/pigbel disease?
Trypsin inhibitors that are found in sweet potatoes
102
What food is classically a/w pigbel disease?
Pork products.
103
Presentation of C. perfringens
Incubation for 6-24 hours
| Water diarrhea and crampy abd pain. Fever and vomiting is rare.
104
What does C. perfringens Type A cause
Gas gangrene
105
What does C. perfringens B and D cause?
Nothing in humans.
106
Diagnosis of C. perfringens?
Culture of both stool and food
| Toxin testing of both food and stool.
107
Treatment of C. perfringens?
Self limited
| Supportive
108
Presentation of staph gastritis?
| Pathophys?
Vomiting 1-6 hours after eating
Resolves in 1-2 days
Due to a heat stable toxin that may be present after cooking and pasteurization.
109
What causes scombroid?
Incorrect storage of fish above 4 C resulting in bacterial overgrowth and a build up of toxic levels of histamine and other biogenic amines by the bacterial enzyme histidine decarboxylase
110
Responsible bacteria for scombroid? [7]
1. E. coli
2. Klebsiella
3. Vibrio
4. Proteus
5. Clostridium
6. Salmonella
7. Shigella
111
Other than fish what else can cause scombroid?
Raw milk contaminated before production of Swiss Cheese
112
Fish known to cause scombroid [11]
1. Tuna
2. Mackerel
3. Skip jack
4. Bonito
5. Dolphin Fish
6. TIlapia
7. Salmon
8. Swordfish
9. Trout
10. Sardines
11. Anchovies
113
What does the fish that cause scombroid taste like?
Peppery, bubbly, spicy.
114
Presentation of scombroid
```
Flushing, uncomfortable warmth
HA
Diarrhea
Urticarial rash on face and upper extremities
Hypotension
Dizziness
Bronchospasm with respiratory distress
Presents in minutes to hours
```
115
What medications make scombroid worse? [2]
1. MAOIs
| 2. Isoniazid
116
Mgmt of mild scombroid
Antihistamines for 24-48 hours
117
Mgmt of Moderate to severe scombroid
H1 AND H2 blockers in combo
| If resp or cardiac compromise treat as anaphylaxsis
118
What is ciguatera poisoning?
Foodborne illness caused by consumption of reef fish contaminated with multiple toxins which arise from dinoflagellates.
119
Common fish affected by ciguatera
1. Barracuda
2. Amberjack
3. Moray eel
4. Parrotfish
120
Do fish with ciguatera look, smell, or taste different?
No
121
Ciguatera poisoning presentation?
Variable with GI, neurologic, and cardiovascular complications. Presents in 3-30 hours after eating fish
122
GI manifestations of ciguatera
1. Diarrhea
2. Abd pain
3. Vomiting
Self limited
123
Neurologic manifestations of ciguatera
```
Weakness
Paresthesia
HA
Vertigo
Pruritis
Hallucinations.
May persist for weeks to months [20%]
--> Reversed temp perception
--> Feeling of loose teet
```
124
Cardio manifestations of ciguatera
Hypertension, bradycardia
| Self limited
125
ciguatera diagnosis
Clinical
126
Ciguatera mgmt
Notify health department and poison control
| Supportive
127
Bloody diarrhea with fever vs without and mgmt
With: Camphy, salmonella, shigella
--> Azitho
Without: E. coli O157:H7 or shig toxin E. coli
--> No abx.
128
What will cause worse infection with Yersenia [4]
Hemochromatosis
Iron Overload
Thalassemia
Cirrhosis
129
How does Klebsiella oxytoca present?
Young, healthy patient with fever, bloody diarrhea and leukocytosis. History of taking a penicillin derivative abx.
130
Treatment of Klebsiella oxytoca
Discontinue offending abx.
131
What does C-scope show with Klebsiella oxytoca?
Right sided hemorrhagic colitis
132
How does proctitis present and what organisms cause this? [4]
Pain with BM in MSM
1. Gonorrhea
2. Syphilis
3. Chlamydia
4. HSV
133
How does proctocolitis present? What organisms cause this?
Painful BM with low volume diarrhea
1. Camphy
2. Shigella
3. E. Histolytica
4. LGV chlamydia
134
Organisms that cause lead to hemolytic anemia? [2]
Camphy
| Yersinia
135
Organisms that can lead to glomerulonephritis? [3]
1. Shigella.
2. Campy
3. Yersinia
136
Organisms that can lead to IgA nephropathy? [1]
Camphy
137
What is Ekiri syndrome? What organism lead to this?
Lethal toxic encephalopathy with seizure
| Shigella
138
Ddx for chronic diarrhea?
1. IBD
2. Malabsorption
3. IBS
4. Celiac/Lactose intolerance
5. Parasites, infection
139
Organisms a/w poultry? [4]
1. Camphy
2. Salmonella
3. C. perfringens
4. Staph aureus
140
Organisms a/w beef? [2]
1. STEC
| 2. C. perfringens
141
Organisms a/w unpasteurized milk or dairy? [7]
1. Salmonella
2. Camphy
3. Listeria
4. Coxiella
5. M. bovis
6. C. perfringens
7. Staph
142
Organisms a/w pork chitterlings? [1]
Yersinia
143
Organisms a/w undercooked eggs [2]
1. Camphy
| 2. Salmonella
144
Organisms a/w raw shellfish [4]
1. Vibrio
2. Plesiomonas
3. Norovirus
4. Hep A
145
Organisms a/w drinking chlorinated water? [1]
Aeromonas
146
Organisms a/w swimming in treated pool water?
Cryptosporidium
147
What foods are a/w C. Botulinum? [6]
1. Home canned foods
2. Prison brew
3. Honey
4. Fermented tofu or beans
5. Aged fish
6. Whales, seals, beavers
148
How does food borne botulism present?
1. GI symptoms: N/V/D, dry mouth/sore throat, abd pain
Followed by..
2. Neuro symptoms: Descending paralysis
149
Diagnosis of food borne botulism?
1. Toxin detection
150
Treatment of food borne botulism?
Antitoxin
| NO ABX
151
How does puffer fish toxin present?
Numbness of face and extremities + sensation of doom
Ascending paralysis
Resp and circulatory failure
--> 30 min to hours after ingestion
152
How does paralytic shellfish poisoning present?
Motor weakness, paralysis, facial and perioral paresthesias, ataxia, nausea,
vomiting, difficulty swallowing, respiratory compromise
Onset in 30 min to 4 hours
153
How does Ingestion neurotoxic shellfish poisoning present?
GI symptoms with paresthesias of face, mouth and extremities, ataxia, muscle aches, diarrhea, abdominal cramps, reversed temperature perception, headaches, respiratory difficulty.
154
How does inhalation neurotoxic shellfish poisoning present?
Nasal and respiratory irritation, rhinorrhea, bronchoconstriction.
155
How does Diarrheic shellfish poisoning present
Diarrhea, nausea and vomiting, abdominal cramps, chills
156
How does Amnesic shellfish poisoning present?
GI symptoms < 24hr followed by neurological < 48Hr
Mental status changes, CN palsies, amnesia, autonomic
Dysfunction, seizures, coma
157
Ddx of acute [<7 days] watery diarrhea?
1. Enteric viruses
2. Toxins [B cerus, C perfringens]
3. Travelers diarrhea [ETEC, EPEC, EAEC,]
4. Aeromonas if water exposure
5. Raw seafood: Plesiomonas
6. Vibrio
158
Diagnosis of acute watery diarrhea
Clinical, usually no studies.
159
Why are abx avoided in travelers diarrhea?
Increased carriage of ESBLs
160
Mgmt of mild traveler's diarrhea? [2]
1. Loperamide
| 2. Pepto
161
Presenting feature of listeriosis?
FEBRILE acute watery diarrhea 1 day after ingestion lasting <2 days.
162
Treatment of listeriosis?
Supportive
| Amox if immunosuppression or pregnant
163
How do you differentiate vomiting from toxin producing bacteria from a virus?
Toxin producing bacteria onset is HOURS
| Virus is ~1 day
