GI Infections Flashcards

1
Q

Gastroenteritis

A

inflammation of the stomach/intestine. Nausea, diarrhea, vomiting, cramps, malaise, anorexia, myalgias, HA.

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2
Q

Viral Gastroenteritis treatment

A

oral re hydration with electrolytes and sugar. No role for antibiotics.

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3
Q

Viral Gastroenteritis etiologies

A

Rotavirus, enteric adenovirus, caliciviruses (norovirus).

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4
Q

Infant viral diarrhea

A

less than 2 years old. Transmission occurs even with good sanitation because caregiver can act as the reservoir. Usually rotavirus and enteric adenovirus.

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5
Q

Viral diarrhea outbreaks

A

Usually norovirus. Fecally contaminated food. Effects older children and adults.

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6
Q

Rotavirus

A

Endemic severe diarrhea of infants. Humans act as the reservoir.

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7
Q

“winter vomiting disease”

A

Rotavirus. Starts in the southwest (november) and spreads northeast until may.

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8
Q

Rotavirus Course length

A

5-7 days

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9
Q

Rotavirus symptoms

A

fever and vomiting.

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10
Q

Enteric Adenovirus

A

Endemic diarrhea of infants

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11
Q

Enteric Adenovirus Symptoms

A

Diarrhea, fever and vomiting

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12
Q

Enteric Adenovirus Course

A

Occurs anytime of year. Lasts 5-12 days.

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13
Q

Calicivirus (norovirus)

A

Epidemic of diarrhea/vomiting in older children and adults.

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14
Q

Calicivirus (norovirus) Course

A

Self-limited 24-48 hours.

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15
Q

Calicivirus (norovirus) associaiton

A

Food, especially shellfish. Can spread person-to-person (cruise ships).

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16
Q

Cholera Etiology

A

Vibrio Cholerae. Colonize the small intesine mucosa with no change in physical integrity. High dose pathogen.

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17
Q

Cholera description

A

Gram negative, bent rod, nonspore forming, facultative anaerobe, motile (polar flagellum).

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18
Q

Cholera symptoms

A

Acute. Watery diarrhea (rice water stools), muscle cramps, wrinkled skin (washerwoman’s hands), poor turgor, sunken eyes, missing peripheral pulses. Hypovolemic shock, metabolic acidosis and death.

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19
Q

Cholera toxin

A

Choleragen. Creates the watery diarrhea. Same toxin as enterotoxigenic E. coli.

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20
Q

O-1 Cholera

A

Classic epidemic cholera

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21
Q

O-139 Cholera

A

newly recognized in south asia. Can cause disease in those already immune to O-1.

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22
Q

Cholera treatment

A

Replace fluids and electrolytes. Antibiotics may shorten the course of the disease.

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23
Q

Cholera reservoir

A

Marine coastal areas and estuaries. Can then spread through contaminated drinking water and food (sushi, oysters).

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24
Q

Cholera vaccines

A

Shanchol and Dukoral

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25
Cholera prevention
Proper sewage control and sanitation.
26
V. Parahaemolyticus reservoir
coastal ocean areas and estuaries. Recedes during the winter.
27
V. Parahaemolyticus Symptoms
Gastroenteritis to a mild cholera-like illness
28
V. Parahaemolyticus prevention
Proper refrigeration especially of seafood.
29
V. Vulnificus Reservoir
coastal waters, especially oysters. Recedes during winter.
30
V. Vulnificus presentation
1.) wound infections 2.) acute self-limiting diarrhea (oysters) 3.) sepsis: bullous skin lesions, shock, liver dysfunction. High death rate ~50%
31
Excherichia coli causes
changes in the gut structure by making pedicles. O antigen=serogroup, H antigen=serotype.
32
086 E. coli
Normal flora
33
055 E. coli
Disease causing
34
Enterotoxigenic E. coli (ETEC)
Common cause of food poisoning outbreaks. Resembles V. cholerae (same toxin). Travelers diarrhea.
35
ETEC symptoms
afebrile with watery diarrhea.
36
Enterohemorrhagic E. coli (EHEC) strain
0157:H7
37
EHEC reservoir
Cows. Beef, raw milk. Can have person-to-person transmission. Veggies may become cross contaminated with cow manure.
38
EHEC toxin
Shiga toxin. Named shiga toxin producing E. coli (STEC).
39
EHEC symptoms
Diarrhea that becomes bloody after 1-3 days of cramps and vomiting. Half also have fever.
40
EHEC complications
hemolytic uremic syndrome (HUS): kidney failure due to clots.
41
EHEC Diagnosis
Can't ferment sorbitol so appears white on MacConkey's agar. Have to request this from the lab if EHEC is suspected.
42
EHEC Treatment
Re hydration. Avoid antibiotics (causes huge release of shiga toxin at once). Don't use anti-motility agents in kids.
43
Enteroaggregative E. coli strain
0104:H4
44
Enteroaggregative E. coli Reservoir
Alfalfa sprouts. High fatality due to large amounts of shiga toxin.
45
Campylobacter jejuni description
Gram negative, curved rod, motile, microaerophilic, grows best at 42 degrees C.
46
Campylobacter jejuni reservior
Birds. Transmission usually occurs due to undercooked chicken. Peaks in summer. Low dose pathogen.
47
Campylobacter jejuni Prodrome
fever, HA, malaise, myalgias usually 12-24 hours before onset of diarrhea.
48
Campylobacter jejuni symptoms
Enteritis with diarrhea, fever, abdominal pain (mimics appendicitis). Self-limiting, improves in several days.
49
Campylobacter jejuni Carrier
Convalescent carrier for 2-3 weeks.
50
Campylobacter jejuni epidemiology
Young adults
51
Campylobacter jejuni complications
Reiter's syndrome and guillian-barre syndrome
52
Campylobacter jejuni diagnosis
Prescence of a prodrome and fever.
53
Helicobacter Pylori Reservoir
Humans.
54
Helicobacter Pylori Description
Gram negative, curved rods, highly motile, stain best with a tissue biopsy and giemsa. Copious production of urease.
55
Helicobacter Pylori Symptoms
Active gastritis: cramps, halitosis, nausea, vomiting. Peptic ulceration: invades mucosa and creates urease leading to ulceration. Can lead to stomach adenocarcinoma.
56
Helicobacter Pylori diagnosis
histological detection with biopsy pluse culture. Can detect urease activity with the CLO test.
57
Helicobacter Pylori treatment
Antibiotics (tetracycline) with bismuth containing drugs.
58
Shigella Description
Highly infectious enteric pathogen. Gram negative, nonspore forming, facultative anaerobe, nonmotile, nonlactose fermenting (differentiates between E. coli).
59
Shigella symptoms
fever, cramps, vomiting, watery diarrhea that progresses into dysentery (blood, mucous, PMNs in the stool).
60
Shigella Transmission
person-to-person. Most common in kids 1-4 years old.
61
Shigella Diagnosis
Suspect in any patient with a fever and diarrheal disease. Acute onset with blood/mucous in the feces. Microscopic eval will show PMNs and RBCs.
62
Shigella Treatment
Self-limitng, fluid replacement. Very antibiotic resistant but an effective antibiotic can shorten the duration and eliminate carriers.
63
Shigella complications
Long term carrier state, Reiter's syndrome, HUS.
64
Shigella species
A: S. dysenteriae B: S. Flexneri (US) C: S. boydii D: S. sonnei (US)
65
Salmonellae Reservoir
Normal gut flora in cows, pigs, chickens, cats, dogs, and reptiles. During the summer and fall. Due to improper food handling.
66
Salmonellae symptoms
sudden onset of fever, chills, cramps, diarrhea, vomiting that lasts 2-3 days. Can be convalescent carrier for months.
67
Salmonellae high risks
very young and very old. Cancer, aids, DM, antibiotic use.
68
Salmonellae description
Gram negative, nonspore forming, facultative anaerobe, motile, non lactose fermenting.
69
Salmonellae diagnosis
Microscopic: fecal leukocytes. Culture. Presence of blood if feverish. Flourescent antibody tests. Serological confirmation.
70
Salmonellae Treatment
supportive. Antibiotics only if the disease becomes systemic.
71
Clostridium difficile description
Gram positive, rods, anaerobic, spore forming.
72
C. diff causes
Antibiotic induced pseudomembranous colitis. Antibiotics: clindamycin, cephalosporins, ampicillin and some antineoplastics.
73
C. diff Presentations
1. ) diarrhea with cramping 2. ) sever colitis: profuse diarrhea, pain with systemic infection (fever, nausea, malaise) 3. ) Classic psuedomembranous colitis: elevated yellow plaques over inflamed regions of mucosa. Psueomembranes (fibrin mesh of necrotic cells) present in feces.
74
C. diff diagnosis
toxin detection with latex agglutination test. Gram stain (positive).
75
C. diff treatment
supportive. Discontinue offending antibiotics.
76
Clostridium perfringens type A description
Acute food-bourne diarrhea. Gram positive, non motile, aerotolerant, spore forming.
77
Clostridium perfringens type A Transmission
Consumption of grossly contaminated meat/poultry. Cooked food is then left out too long.
78
Clostridium perfringens type A Diagnosis
Must isolate large numbers form the feces and the food.
79
Clostridium perfringens type A symptoms
Short incubation. Moderate-severe diarrhea and cramping with complete recovery in about a day.
80
Bacillus Cereus Description
Gram positive, aerobic, motile, spore forming.
81
Bacillus Cereus presentations
1. ) Emetic form: Due to preformed toxin, upper GI symptoms 1-5 hours after ingestion. vomiting, diarrhea, cramps. 2. )Diarrheal form: ingestion of a large number of vegetative cells that produce toxin. abdominal pain, profuse diarrhea. 1-17 hours after ingestion.
82
Bacillus Cereus Diagnosis
Afebrile with quick onset (1-5 hours) of eating. Have to isolate more than 10^5 per gram from the stool.
83
Bacillus Cereus reservoir
Spores are commonly found on grains, veggies and especially rice.
84
Bacillus Cereus prevention
Prompt refrigeration of cooked grains
85
Staphlococcal Presentation
Acute emetic/diarrheal disease (1-6 hours). Nausea, vomiting, diarrhea, cramps, acute salivation. Self-limiting
86
Staphlococcal toxin
Enterotoxin A: water soluble, heat stable. Emetic=enters CNS and vomiting center. Diarrheal=decreased water absorption.
87
Staphlococcal transmission
custard baked goods, canned food, processed meat, potato salad.
88
Staphlococcal reservoir
Humans. Disease without colonization. Second most common cause of food poisoning behind salmonella.