Diarrhoea an Enteric Infection Flashcards

1
Q

What bacteria can cause diarrhoeal illness?

A
  • Salmonella
  • Campylobacter
  • E. coli 0157
  • Shigella
  • Clostridium Difficile
  • Cholera
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2
Q

How long after onset do symptoms of Salmonella associated Diarrhoea present?

A

<48hrs

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3
Q

How long does Salmonella associated diarrhoea normally last for?

A

<10 days

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4
Q

What are the different types of diarrhoea?

A
  • Osmotic Diarrhoea
  • Secretory Diarrhoea
  • Inflammatory Diarrhoea
  • Abnormal motility
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5
Q

What can prolonged carriage of Salmonella be associated with?

A

Gallstone formation

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6
Q

What can be a common problem post-infection for someone who has had Salmonella?

A

Irritable Bowel Syndrome

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7
Q

What species of campylobacter is the main pathogen in diarrhoeal infection?

A

Campylobacter jejuni

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8
Q

What are the most common sources of campylobacter infection?

A
  • Contaminated Milk
  • Chickens
  • Puppies
  • Water
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9
Q

What is the incubation time for Campylobacter?

A

2-5 days

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10
Q

What are the main symptoms of Campylobacter infection?

A
  • Severe Abdominal Pain - often becomes continuous and radiates to right iliac fossa
  • Watery Diarrhoea
    • Can become bloody
  • Fever
  • Nausea and Vomiting
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11
Q

How long does it normally take for Campylobacter infection to clear?

A

3 weeks

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12
Q

How long does it take stools to become negative in Campylobacter infections?

A

6 weeks

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13
Q

What are some of the long term post-infective sequelae of Campylobacter infection?

A
  • Guillain Barre Syndrome
  • Reactive Arthritis
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14
Q

What is secretory diarrhoea?

A

Both active intestinal secretion of fluid and electrolytes as well as decreased absorption

Cholera toxin is regarded as the classic model of this

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15
Q

What are common causes of secretory diarrhoea?

A
  • Enterotoxins
  • Hormones
  • Bile salts (in the colon) - following ileal resection
  • Fatty acids (in the colon) - following ileal resection
  • Some laxatives
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16
Q

What is the pathophysiology of diarrhoea caused by cholera?

A
  • Increases cAMP levels
  • Increases protein kinases
  • Inhibit Na+ and Cl- absorption
  • Cl- secretion
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17
Q

What bacteria cause secretory diarrhoea?

A
  • Cholera
  • E. Coli
  • C. Difficile
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18
Q

How do you distinguish between secretory and inflammatory diarrhoea?

A

Inflammatory diarrhoea is accompanied by PAIN AND FEVER

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19
Q

What is osmotic diarrhoea?

A

Gut mucosa acts as a semipermeable membrane and fluid enters the bowel if there are large quantities of non-absorbed hypertonic substances in the lumen

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20
Q

What can cause osmotic diarrhoea?

A
  • Non-absorbable substance
  • Malabsorption so that high concentrations of solute remain in the lumen
  • Specific absorptive defect - coeliac disease
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21
Q

How can you distinguish between osmotic diarrhoea and other types of diarrhoea?

A
  • Remove the malabsorptive substance
  • Bloating?
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22
Q

What is inflammatory diarrhoea?

A

Damage to the intestinal mucosal cell so that there is a loss of fluid and blood

In addition, there is defective absorption of fluid and electrolytes

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23
Q

What are the causes of inflammatory diarrhoea?

A
  • Infection (Shigella)
  • Inflammatory conditions (UC, Crohn’s)
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24
Q

What can cause diarrhoea due to abnormal motility?

A
  • Diabetic (arse)
  • Post-vagotomy
  • Thyrotoxicosis
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25
Q

What are the clinical features of Salmonella infection?

A
  • Diarrhoea
  • Vomiting
  • Fever
  • Septicaemia
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26
Q

What type of E. Coli causes Enterohaemorrhagic E. Coli infection?

A

E. Coli O157:H7

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27
Q

What is the reservoirs of E. Coli O157?

A

Cattle

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28
Q

What are the clinical features of E. Coli O157?

A

Frequent Bloody Stools

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29
Q

What can E. Coli O157 cause?

A

Haemolytic Uraemic Syndrome

30
Q

What is Haemolytic Uraemic Syndrome (HUS)?

A

Shiga-Like Toxin (SLT) binds to globotriaosylceramide -> platelet activation stimulated -> microangiopathy

Platelets bind to endothelial, glomerular, tubular and mesangial cells

31
Q

Who does HUS most commonly occur in, if it does occur?

A

Children and the Elderly

32
Q

How long after the onset of diarrhoea can it take for HUS to develop in E. Coli O157 infection?

A

5-9 days

33
Q

What is the definition of Food Poisoning?

A

Illness caused by eating contaminated foodstuffs

34
Q

What bacteria can cause food poisoning?

A
  • Staphylococcus Aureus
  • Bacillus cereus (re-fried rice)
  • Clostridium Perfringens
35
Q

What is Dysentery?

A

Infection of the intestine causing severe diarrhoea with blood and mucus

36
Q

What causes bacillary dysentery?

A

Shigella

37
Q

What are the symptoms of bacillary dystentery?

A
  • Abdominal pain
  • Small volume Bloody diarrhoea + mucus
  • Sudden fever
  • Nausea
38
Q

What is the incubation period for bacillary dysentery?

A

1-6 days

39
Q

How is bacillary dysentery spread?

A

Faecal-Oral

40
Q

How is cholera spread?

A

Faecal-Oral route

41
Q

Can you name the organism which causes cholera?

A

Vibrio Cholerae (Gram -ve rod)

42
Q

How long does it take cholera to incubate?

A

A few hour to 5 days

43
Q

What are the clinical features of Cholera?

A
  • Profuse watery stools (1L/h)
  • Fever
  • Vomiting
  • Rapid dehydration
    • Associated Metabolic Acidosis
44
Q

What can be a complication of Shigella Infection?

A
  • HUS
  • Seizures
45
Q

What is the definition of Colitis?

A

Inflammation of the colon

46
Q

What are colitic symptoms?

A
  • Recurring bloody diarrhoea +/- pus
  • Lower Abdominal Pain
  • Faecal Incontinence
  • Fatigue
  • Unexplained Weight loos
47
Q

What is Gastroenteritis?

A

Inflammation of the stomach and intestine

48
Q

What can cause Gastroenteritis?

A

Usually due to viral, bacterial infection or food-poisoning toxins

49
Q

How do you objectively determine if someone has developed Gastro-enteritis?

A

3+ stools in 24 hrs, plus one of

  • Fever
  • Vomiting
  • Pain
  • Blood/mucus in stools
50
Q

How long does gastroenteritis normally last?

A

3-5 days

51
Q

What are the main features of gastroenteritis?

A

Dirrhoea +/- vomiting

52
Q

What are the 4 main pathogenic mechanisms of bacterial gastroenteritis?

A
  • Mucosal adherence - effacement of intestinal mucosa
  • Mucosal invasion - Penetration and destruction of mucosa
  • Toxin production enterotoxin - Fluid secretion without mucosal damage
  • Cytotoxin - Damage to mucosa
53
Q

For each of the 4 pathogenic mechanisms of bacterial gastroenteritis, describe their clinical presentations

A
  • Mucosal adherence - Moderate watery diarrhoea
  • Mucosal invasion - Dysentery
  • Toxin Production - Profuse Watery diarrhoea
  • Cytotoxin - Dysentery
54
Q

What bacteria can cause gastroenteritis?

A
  • Salmonella
  • Campylobacter
  • Shigella
  • EHEC
  • ETEC
  • Cholera
55
Q

What organism causes pseudomembranous colitis?

A

C. Difficile

56
Q

How does C. diff cause diarrhoea?

A
  • Toxin A - enterotoxin
  • Toxin B - cytotoxic
57
Q

How does C. diff infection present?

A
  • Severe Bloody Diarrhoea
  • Abdominal Pain
  • Gut perforation
  • Toxic Megacolon
58
Q

What are the 4 C’s which put a patient at risk of C. diff colonisation?

A
  • Cephalosporins
  • Clindomycin
  • Clarythromycin
  • Co-Amoxiclav
59
Q

How would you manage someone with C. diff infection?

A

Stop causative ABx

10 days of treatment

  • Non severe - Metranidazole - 400 mg 8hrly
  • Severe - Oral Vancomycin - 125 mg 6 hrly
60
Q

What is the most common cause of traveller’s diarrhoea?

A

Enterotoxigenic E. Coli

61
Q

What parasites can cause diarrhoea?

A
  • Cryptosporidium parvum
  • Giardia lamblia
  • Entamoeba histolytica
62
Q

What can be a complication of Entamoeba Histolytica?

A

Amoebic Liver Abscess

63
Q

How does Entamoeba Histolytica Present

A

Similar to ulcerative colitis

64
Q

How does giardia infection present?

A
  • Explosive Diarrhoea
  • Malabsorption
  • Bloating
  • Flatulence
  • Weight loss
65
Q

Where does giardia colonise in the gut?

A

Duodenum and jejunum

66
Q

How would you treat giardia infection?

A
  • Metranidazole
  • Tinidazole
67
Q

How does Rotavirus cause diarrhoea?

A

Infects mature enterocytes of villous body and tip (not crypts) with cell death and lactose intolerance

68
Q

How would you assess someone with suspected gastro-enteritis?

A
  • Symptoms and their duration - >2/52 unlikely to be infective gastro-enteritis
    • Frequency
    • Quality
    • Blood/Mucus
  • Risk of food poisoning - Dietary, contact, travel history
  • Assess hydration - postural BP, skin turgor, pulse
  • Features of sepsis - fever, raised WCC
69
Q

How would you investigate someone with suspected gastro-enteritis?

A
  • Stool culture
  • Blood culture
  • Renal function
  • Blood count - neutrophilia, haemolysis
  • Abdominal X-Ray - if abdomen distended, tender
70
Q

What would make you suspect a non-infectious cause for diarrhoea?

A

>2 weeks duration