Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Yr 2 Gastrointestinal > Wk 3 - Symposium 3 (Clinical): GI Infections > Flashcards

Wk 3 - Symposium 3 (Clinical): GI Infections Flashcards

1
Q

What are the two classifications of gastro-intestinal/intra-abdominal infections?

A
  1. Intra-luminal: Usually due to ingestion of a exogenous pathogen (non-commensal) e.g. Infective gastro-enteritis
  2. Extra-luminal: Usually due to introduction / spillage of endogenous normal gut commensal flora into extra-luminal site. e.g. Intestinal perforation – peritonitis, Intra-abdominal abscesses, Blocked biliary tree: cholangiitis, liver abscesses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

List some of the GI tract’s defences against infection.

A
  1. Mouth and oesophagus: flow of liquids, saliva, lysozyme, normal flora
  2. Stomach: acidic pH
  3. Small intestine: Flow of gut contents, peristalsis, mucus, bile, IgA, lymphoid tissue (Peyer’s patches), shedding and replacement of epithelium, normal flora
  4. Large intestine: Normal flora, peristalsis, shedding and replication of epithelium, mucus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the different pathogenetic mechanisms of enteric bacteria.

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

Most GI pathogens clinically manifest in a very similar way…

A
  • Diarrhoea (watery of blood)
  • Vomiting
  • Abdominal pain and tenderness
  • with or w/o fever
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is diarrhoea classified?

A
  1. Community-acquired: Presenting with diarrhoea in community or within first 72hrs of admission
  2. Hospital (nosocomial)-acquired: Presenting with diarrhoea >72hrs after admission to hospital
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Diarrhoea can be ____ or ____.

A

Diarrhoea can be secretory or inflammatory.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does a child with infantile diarrhoea present clinically?

A
  • Listless, irritable child. Poor feeding
  • Watery stool (no blood)
  • Failure to thrive
  • May progress to severe dehydration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What agents usually cause infantile diarrhoea?

A
  • Viruses: Rotavirus, Adenovirus
  • Bacteria: Enteropathogenic Escherichia coli (EPEC) [destroy microvilli]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does a patient with travellers diarrhoea present clinically?

A
  • Watery diarrhoea, malaise
  • 5-15d after arrival in foreign country
  • Self-limits in 1-5d
  • 20-50% have illness >5d
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What pathogens usually cause travellers diarrhoea?

A
  • Minority be due to agents such as cholera, salmonella, shigella, amoebas but most >50% are due to:
  • Enterotoxigenic Escherichia coli (ETEC) strains
  • Heat-labile and heat-stable toxins.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is cholera?

A
  • Vibrio cholerae
  • Curved Gram negative rod. Salt-tolerant.
  • Toxin mediated illness- A/B subunit toxin binds to enterocyte and causes irreversible activation of adenyl cyclase » inhibition of Na+ and Cl- uptake » excretion of H20 » DIARRHOEA+++
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

List the two strains of cholera that cause disease.

A

O1 and O139 strains toxigenic and cause disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does a person with cholera present clinically?

A
  • Abrupt onset of profuse watery diarrhoea (rice water stool). Fever unusual.
  • Dehydration kills: can lose up to 1 litre fluid/hr.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Cryptosporidium?

A
  • Protozoan - a microscopic parasite that causes the diarrheal disease cryptosporidiosis. Both the parasite and the disease are commonly known as “Crypto.”
  • Faecal-oral. Ingestion of 1-5 oocysts enough.
  • Oocysts highly resistant to disinfectants
  • Waterborne > person to person
  • Worldwide (including UK)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the main toxins causing community-acquired secretory diarrhoea?

A
  • Staphylococcus aureus
  • Bacillus cereus
  • Clostridium perfringens
  • Algal food poisoning (dinoflagellates): shellfish
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the most common cause of inflammatory diarrhoea (in the UK)?

A

Campylobacter jejuni

Curved (seagull shaped) Gram-negative rods

Commonest bacterial gastro-enteritis in UK

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

What is one post-infectious complication of campylobacter?

A

Guillian-Barre Syndrome

18
Q

What are the two different types of salmonella infections?

A
  • Non-typhoidal / “food poisoning”
    • Worldwide, incl UK
    • Rare systemic infection
    • Antibiotic treatment sometimes required
  • Typhoidal / enteric fevers
    • Tropical, imported infections
    • Always involve systemic infection
    • Antibiotic treatment always required
19
Q

In typhoid (enteric fever caused by salmonella typhi and paratyphie), patients are more likely to present with ____ than ___ (diarrhoea/constipation).

A

In typhoid (enteric fever caused by salmonella typhi and paratyphie), patients are more likely to present with constipation than diarrhoea.

20
Q

What is the most common strain of VTEC E.coli?

A

E. coli O157 most common VTEC strain.

21
Q

In E.coli infections, antibiotics may…

A

Antibiotics may worsen the situation –> result in increase toxin release

22
Q

The most common cause of hospital-acquired diarrhoea is…

A

Clostridium difficile

23
Q

Describe the pathophysiology of Clostridium difficile infection (CDI).

A

1) Broad-spectrum antibiotic administration
2) Abolition of “colonisation resistance”
3) Ingestion of C.difficile spores from the environment (may be endogenous in some patients)
4) Spore germination in GI tract
5) Growth and proliferation of C.difficile bacilli

6) Toxin production. Trigger for this unknown- ?stress response/ nutrient depletion or cell-cell signalling (quorum sensing)

7) Toxin binding to colonic mucosa- resulting inflammation can range from mild to severe (colitis)
8) Diarrhoea results in massive spore release into environment

24
Q

_____ precipitate Clostridium difficile infections.

A

Antibiotics precipitate Clostridium difficile infections.

25
Q

Clostridium difficile is treated by…

A

Vancomycin (+diarrhoea and other symptoms can take 1-2 weeks to respond)

+ Metronidazole in life-threatening CDI

26
Q

Acute diarrhoea is somewhat arbitrarily defined as diarrhoea for less than ____.

A

Acute diarrhoea is somewhat arbitrarily defined as diarrhoea for less than four weeks.

27
Q

Who should be investigated when they present with diarrhoea?

A
  • Anyone in the hospital or recently been (with antibiotics)
  • Diarrhoea lasting for more than a week
  • Travel history
  • Blood in the stool
  • Fever or Evidence of dehydration or a mass or Weight loss.
  • Sepsis and diarrhoea
  • High inflammatory markers e.g. C reactive protein
  • High-risk groups include immunocompromised e.g. HIV, older people and those with comorbidities
  • Investigating potential outbreaks (looking for a carrier e.g. in Salmonelosis)
28
Q

What history needs to be included to help determine diagnostic methods for faecal samples?

A
  • Clinical features:
    • Systemic illness, fever, bloody stool
    • Symptoms; duration, recurrent, chronic
    • Severe abdominal pain
    • Immunosuppression
  • Epidemiological setting:
    • Food intake e.g. barbecue; restaurant; eggs; chicken; shellfish
    • Recent foreign travel and to which country (OCP)
    • Recent antibiotic, PPI or hospitalization (C difficile)
    • Family or nursing home; (Norovirus)
    • Exposure to untreated water (protozoa) or animals
    • Contact with other affected individuals or outbreak
29
Q

What would you do to reduce infectious diarrhoea in the hospital?

A
  1. Always check local guidelines
  2. All patients presenting with symptoms of gastrointestinal infection should be regarded as infectious to others until a microbiological cause has been excluded.
  3. Isolate these patients for a period of 48 hours symptom free, ideally access to ensuite facilities. Keeping doors closed on infected bays/wards Minimal movement of staff between wards
  4. If an outbreak of infectious intestinal disease is suspected for example more than two patients and/or staff members are affected, the Infection Control Team must be informed immediately.
  5. Ensure that staff and patients observe hand hygiene (soap and water) and Personal protection guidelines
  6. The housekeeping team leader must be informed for extra cleaning
  7. Symptomatic staff must be excluded from work until they have had a period of 48 hours clear after their last symptom (+/ - Stool sample to OCH or GP)
  8. Patient discharge: There is no need to delay if the patient is to be discharged to his/her own home.
  9. Communication: if you are sending to other care fasciitis
30
Q

What is entamoeba histolytica?

A

Entamoeba histolytica is well recognized as a pathogenic amoeba, associated with intestinal and extraintestinal infections.

31
Q

How is entamoeba histolytica transmitted?

A

Faecal-oral transmission

32
Q

In brief, describe the pathogenesis of entamoeba histolytica.

A
  • Trophozoites: invasion –> flask-shaped ulcers (bloody diarrhoea/ amoebic dysentry) –> Complications: Amoebic Peritonitis or Bacterial Peritonitis.
  • Amoeba –> blood –> Liver Abscesses (anchovy paste).
33
Q

How is entamoeba histolytica diagnosed?

A
  • Fresh stool sample x 3
  • Colonoscopy
  • US/CT
  • Serology: Invasive disease/
  • PCR from stool of pus (in liver or lungs)
34
Q

How is entamoeba histolytica treated?

A
  • Metronidazole + Diloxanide
  • Furate or Paramomycin (intralumenal cysts)
  • Aspiration of abscess (usually do not need draining unless very big)
35
Q

What is giardiasis?

A

Giardiasis is an enteric infection caused by the protozoa Giardia duodenalis. A common disease in low-resource settings, it often presents with flatulence and watery diarrhoea.

36
Q

How is giardiasis diagnosed?

A

Stool sample

37
Q

How is giardiasis treated?

A

Metronidazole or Tinidazole

38
Q

What is enterobius vermicularis?

A

Enterobius vermicularis is an organism that primarily lives in the ileum and cecum. Once E. vermicularis eggs are ingested, they take about 1 to 2 months to develop into adult worms which happens in the small intestine. These do not usually cause any symptoms when confined to the ileocecal area.

39
Q

How is enterobius vermicularis diagnosed?

A
  • Visualing adult worms
  • Clear sticky tape slide and microscopy Ova: 55 x 25 um
    • sample:50% detection rate
    • 3 samples :90% detection rate
40
Q

How is enterobius vermicularis treated?

A
  • Piperazine or Mebendazole; Simultaneously treat all family members and/or classmates who are infected.
  • Prescribe drugs at least 3 times at 3-week intervals.
41
Q

Individuals infected with hookworms usually present with…

A

Cutaneous manifestation, pulmonary manifestation, Iron deficiency anaemia and malnutrition

Yr 2 Gastrointestinal (37 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions