Diarrhoea

Question 1

define Gastro-enteritis

Answer 1

3+ stools in 24hrs plus at least one of fever, vomiting, pain, blood/mucus stools

Question 2

epidemiology of GI infections

Answer 2

Campylobacter and Salmonella contamination in intensively farmed livestock. Storage and distribution of eggs allows multiplication of organisms to infecting doses. International distribution. Personm to person (norovirus)

Question 3

what are the defenses against enteric infections?

Answer 3

hygiene, gastric acid, gut motility, normal flora, gut immunity

Question 4

clinical features of Non-inflammatory diarrhoeal illness

Answer 4

Secretory toxin-mediated = cholera - increases cAMP levels and Cl, Na and K secretion leading to water loss from the gut/ enterotoxigenic E. coli = travellers’ diarrhoea.
frequent watery stools with little abdo pain
rehydration mainstay of therapy

Question 5

clinical features of Inflammatory diarrhoeal illness

Answer 5

Bacterial infection usually
Abdo pain, bloody stools, sytemic upset (fever)
Rehydration and (sometimes) antimicrobials required

Question 6

How would you assess the patient?

Answer 6

• Symptoms - duration diarrhoea, frequency and “quality” of stool, other symptoms
• Risk - food, occupation, travel, antimicrobials, contacts, institution
• Examination of hydration, SIRS: Postural BP, Pulse, fever, skin turgor, urine flow, patient appearance, muscle cramps, raised WCC

Question 7

Ix

Answer 7

Stool and blood culture, renal function, blood count (haemolysis), sigmoidoscopy, X-Ray, serology

Question 8

DDX

Answer 8

Inflammatory bowel disease
Spurious diarrhoea -secondary to constipation
Carcinoma
Diarrhoea and fever can occur with sepsis outside the gut

Question 9

Tx

Answer 9

Rehydration, Fasting, Antimicrobials, Treatment of complications

Question 10

outline Campylobacter gastroenteritis…

Answer 10

C jejuni principle pathogen, Incubation up to 7 days, Infection clears within 3 weeks, Severe abdo pain +/- colitic picture, Rarely invasive (immunocompromised) - <1%, Post-infective sequelae

Question 11

outline Salmonella gastroenteritis…

Answer 11

Symptom onset usually <48h after exposure and diarrhoea usually lasts <10 days, <5% have positive blood cultures, Extra-intestinal manifestations uncommon but potentially fatal consensus view on antibiotic treatment, 20% have persistently positive stools at 20/52, 20/75 (27%) have IBS symptoms at 6 months

Question 12

what are the most common isolates of Smalmoella in the UK?

Answer 12

enteritidis and typhimurium

Question 13

outline E.coli 0157:H7 gastroenteritis…

Answer 13

Enterohaemorrhagic E. coli, Recognised as a pathogen in 1982, Cattle reservoir,Excretion over three weeks after symptoms, Increasing incidence (four fold between 1992 and 1996), Produce a shiga-like toxin (SLT), 5-9 days between onset of diarrhoea and HUS, HUS largely (not exclusively) a complication in children and elderly

Question 14

how is HUS (hemolytic-uraemic syndorme) characterised (3 factors)?

Answer 14

renal failure, haemolytic anaemia and thrombocytopenia

Question 15

outline Shigella gastroenteritis…

Answer 15

Largely a disease of childhood/travel, HUS and seizures may complicate, Widespread quinolone use against shigellosis in developing world leading to resistance, Different serotypes hamper development of a universal vaccine

Question 16

what are the most common causes of food poisoning in the UK?

Answer 16

staph.a, bacillus cerus (refried rice), clostridium perfringens (undercooked meat)