Gastroenteritis

Question 1

campylobacter

incubation period and symptoms?

Answer 1

incubation period is around 3-10 days

causes inflammation of the colon and rectum - occasionally invading its way into the blood stream

Question 2

source of campylobacter?

Answer 2

undercooked poultry, infected water and unpasteurised milk

person to person outbreaks are uncommon and a mass outbreak is due to a large group being subject to the same conditions

Question 3

management of Campylobacter?

Answer 3

usually self limiting but give erythromycin or ciprofloxacin for 5 days if systemic symptoms develop

Question 4

incubation period of salmonella enertica?

Answer 4

12-48 hours

Question 5

pathophysiology of salmonella enertica?

Answer 5

inflammation of ileum and colon - bacteria then multiply in the gut and cause mucosal damage - decreasing fluid absorption and increasing fluid release
can also find its way into the blood stream rarely

Question 6

symptoms of salmonella enertica?

Answer 6

abdominal pain, diarrhoea (sometimes bloody), vomiting

Question 7

source of salmonella enertica?

Answer 7

undercooked poultry

Question 8

management of salmonella enertica?

Answer 8

is usually self limiting but give ciprofloxacin if systemic symptoms start

Question 9

incubation period of shigella spp.?

Answer 9

1-9 days

Question 10

pathophysiology of shigella spp.?

Answer 10

invades into he mucosa of the small intestine causing inflammation but doesn’t go any further - so will never be seen in blood cultures

Question 11

symptoms of shigella spp?

Answer 11

abdominal pain, diarrhoea (sometimes bloody and contain pus)

Question 12

source of shigella?

Answer 12

human infection only - person to person contact

Question 13

management of shigella spp.?

Answer 13

usually self limiting - other forms of shigella that are picked up abroad may be more severe and may need treatment with ciprofloxacin

Question 14

E coli 0157 pathophysiology?

Answer 14

this strain of E coli produces a toxin that damages red blood cells and the kidney, causing haemolytic-uraemic syndrome - therefore increasing blood urea, red cell haemolysis and low levels of platelets within the blood

Question 15

what is the toxin called in E coli and what is its mode of action?

Answer 15

verotoxin binds to the receptors found in renal cells, RBC and others - the toxin inhibits protein synthesis and cause cell death

Question 16

source of E coli 0157?

Answer 16

carried as part of normal gut flora in cattle, but becomes contaminated when outside during slaughter - so caused by burgers/mince rather than steak

can also be caused by visits to farms and private untreated water sources which have been infected

Question 17

management of E coli?

Answer 17

symptomatic and supportive treatment only - antibiotics should not be used as they can increase the levels of toxins within the blood - the bloods of a patient with E coli must be checked 1 week after to look for signs of HUS

Question 18

incubation period for typhoid?

Answer 18

14-21 days - the infection are febrile to begin with and they circulate within the bloodstream - causing headaches, flu like symptoms and then diarrhoea 3 weeks later

Question 19

symptoms of typhoid?

Answer 19

fever, rash on abdomen (rose spots) and diarrhoea

Question 20

source of typhoid?

Answer 20

human infection only - spread form person to person from drinking contaminated water, and poor sanitation

Question 21

management of typhoid?

Answer 21

antibiotics are required - resistance to ciprofolxacin is high in developing countries - azithromycin is often used

Question 22

cholera incubation period?

Answer 22

1-9 days

Question 23

pathophysiology of cholera?

Answer 23

organism produces a exotoxin that causes active outpouring of fluid cells from the small intestine - resulting in severe extremely watery diarrhoea (rice water stools) - causing rapid dehydration

Question 24

source of cholera?

Answer 24

person to person spread from contaminated water/poor sanitation

Question 25

management of cholera?

Answer 25

fluid and electrolyte replacement - antibiotics are not indicated

Question 26

pathophysiology of C. Difficle?

Answer 26

The pathogenic c. difficle (anaerobic gram positive spore forming bacillus) dominate the flora when the normal flora of the gut has been disrupted due to antibiotics taken to cure a previous infection

Question 27

what are the host risks for c difficle?

Answer 27

``` age greater than 65 immunosuppressed PPI drugs Hospitalisation/long term care previous C. Diff infection ```

Question 28

prevention of C diff?

Answer 28

prompt isolation and treatment of infected individuals controll antibiotic usage - control the 4 C's - clarthromycin - co-amoxiclav - ciprofloxaccin - clindamycin

Question 29

what GI infections are associated with ingestion of preformed toxins?

Answer 29

- staph aureus - clostridium perfringens - bacillus cereus

Question 30

example of staph aureus infection?

Answer 30

baker touches cream to put on a cake, bacteria multiply in the cream producing a enterotoxin which is ingested by the customer the toxin is absorbed quickly - acting directly on the vagus nerve - vomiting commences within 1-2 hours

Question 31

example of clostridium perfringens infection?

Answer 31

(large gram positive anaerobic bacilli) spores of of the bacteria survive cooking, then for vegetations which produce enterotoxins heavily associated with reheated gravy

Question 32

example of a bacillus cereus infection?

Answer 32

(large gram positive aerobic bacilli) similar to clostridium perfringens infection in that the bacterial spore survive cooking, form vegetations then release enterotoxins heavily associated with inadequately reheated rice

Question 33

examples of short incubation times?

Answer 33

staph aureus and bacillus cereus

Question 34

examples of medium incubation times?

Answer 34

salmonella and clostridium perfringens - the medium incubation time suggest invasion of a toxin within the gut

Question 35

examples of long incubation times?

Answer 35

campylobacter/Ecoli 0157 suggest invasions of toxin within the gut and they are often associated with bloody diarrhoea

Question 36

examples of parasites that cause GI infections?

Answer 36

- cryptosporidium - giardia lamblia - enetrobius vermicularis

Question 37

characteristics of and giadia lamblia cryptosporidium?

Answer 37

‘protozal’ – single organism infection | infection occurs when cysts are ingested and hatch into trophozoites that invade cells within the small intestine

Question 38

source and symptoms symptoms of cryptosporidium?

Answer 38

domestic animals (calves) person to person spread as well as contaminated water and swimming pools diarrhoea that is particularly severe in patients suffering from HIV

Question 39

source, symptoms and treatment of giardia lamblia?

Answer 39

person to person spread - associated with contaminated water supplies diarrhoea, malabsorption syndrome, anorexia, abdominal pain, flatulence oral metronidazole

Question 40

characteristics of a enterbius vermicularia "threadworm" infection?

Answer 40

tiny white worms that look like small pieces of thread when passed in stools – seen in school children and will often infect several members of the family

Question 41

pathophysiology if enetrbius vermicularia?

Answer 41

eggs are ingested, hatch in the intestine and live in the caecum and colon, females then come out to lay eggs in the perianal area at night, child scratches bottom and then puts fingers in mouth symptoms – perianal itch, worms seen in stool

Question 42

source and management of "threadworm" infection?

Answer 42

human to human contact only - poor hygiene oral mebendazole - often has to be used to treat the whole family