Theme 11 L5, L9: GI Infections Flashcards
Which sites of the GI tract are sterile?
- peritoneal space
- pancreas
- gall bladder
- liver
Which sites of the GI tract are non- sterile?
- mouth
- oesophagus
- stomach
- small bowel
- large bowel
What are 3 types of dentoalveolar infections?
- Caries (decay/ cavities) - breakdown of teeth due to acids made by bacteria
- Pulpitis - inflammation of the dental pulp (tissue at centre of tooth)
- Periapical abscess
What are the signs of peridontal infection?
- plaque beneath the gingival margin
- gingivitis (inflammation of gums)
- periodontitis
- periodontal abscess
- acute necrotising ulcerative gingivitis (Vincent’s angina)
Name 2 deep neck space infections?
- Peri tonsillar/ quinsy abscess
2. Acute suppurative parotitis
What is Lemierre’s syndrome?
suppurative jugular thrombophlebitis –> bacteria seen in jugular vein
What is an iatrogenic cause of mucositis? (inflammation of mucous membranes of the GI tract)
-chemotherapy induced
What is a risk factor of chemotherapy induced mucositis?
caries, peridontal diseases
What is Boerhaave syndrome?
rupture of the oesophagus –> a sponteanous perforation of the oesophagus that results from an increase in intra oesophageal pressure
How can oesophageal rupture lead to infection?
-results in contamination of the mediastinal cavity with gastric contents
How do you manage oesophageal rupture?
- avoidance of all oral intake
- nutritional support
- antibiotics, PPI
- drainage of fluid collections
- debridement of infected and necrotic tissue
How is H.pylori transmitted?
person-to-person through faecal-oral / oral-oral
Explain the pathogenesis of H.pylori infection?
bacterial urease hydrolyses gastric luminal urea to form ammonia that helps neutralise gastric acid and form a protective cloud against the organism
What is the classical presentation of cholangitis?
Charcot’s triad:
fever, abdominal pain, jaundice
In a biliary tract infection, what will be elevated in an LFT?
- ALP
- GGT
- billirubin (predominately conjucated)
Explain the symptoms and clinical findings in cholecysitis?
- abdo pain, fever, history of fatty food ingestion one hour or more before initial onset of pain
- elevation in the serum total bilirubin and ALP
- normally associated with gall stones
- +ve murphy’s sign
What can an overgrowth of bacteria result from?
achlorhydia (e.g after gastric surgery) impaired motility blind loops of bowel surgery radiation damage
What is the causative agent of Whipple’s disease?
tropheryma whipplei - ubiquitous in environment
What is Whipple’s diseased characterised by?
rare, multi-system process characterised by four manifestations: joint symptoms (arthralgia), chronic diarrhoea, malabsorption/abdo pain and weight loss
Which parasite can cause liver abscesses?
entamoeba histolytica
What are liver abscesses associated with?
an increased risk of colonic malignancy
What will be elevated in liver abscesses?
serum alkaline phosphatase
How is mycobacterium tuberculosis associated with the GI tract?
-can affect any of the GI tract (ileo-caecal) is most common site
What is pancreatitis mostly associated with?
alcohol use
What is a ‘complicated intra-abdominal infection’?
defined as infection that extends beyond the hollow viscus of origin into the peritoneal space and is associated with either abscess formation or peritonitis
e.g appendicitis is uncomplicated but perforated appendicitis is
What is the difference between complicated and uncomplicated diverticulitis?
-antibiotics have no proven efficacy for uncomplicated diverticulitis
What is the difference between diverticulosis and diverticulitis?
Diverticulosis = mere presence of diverticula
Diverticulitis = inflammation and complications of diverticula
What is an intra-peritoneal abscess?
localised area of peritonitis with a build up of pus
What are the pre-disposing factors to intra-peritoneal abscess?
perforation, peptic ulcer, perforated appendix or diverticulum, bowel infarction, pancreatitis, penetrating trauma, post-operative anastomotic leak
How do we treat an intra-abdominal abscess?
drainage combined with therapy
How does an intra-peritoneal abscess present?
- Non-specific
- Sweating, anorexia, wasting
- Swinging pyrexia
- Localising features
- Subphrenic abscess: pain in shoulder on affected side, persistent hiccup, intercostal tenderness, apparent hepatomegaly (liver displaced downwards, ipsilateral lung collapse with pleural effusion)
- Pelvic abscess: urinary frequency, tenesmus
What is SBP and how is it defined?
spontaneous bacterial peritonitis:
ascitic fluid infection without an evident intra-abdominal surgically treatable source
What is the aetiology behind SBP?
bacteria within the lumen cross the intestinal wall into mesenteric lymph nodes. Lymphatics carrying the contaminated lymph ruptures because of the high flow and high pressure associated with portal hypertension. Seeing of ascitic fluid via the blood also occurs
Which bacteraemia can patients with bowel cancer present with?
streptococcus bovis (now called S.gallolyticus)
What is S.bovis/S.gallolyticus bacteraemia also associated with?
endocarditis
What is angular cheilitis?
a mild infection at the side of the mouth caused by S.aureus or candida
What is the name of white lesions on the tougue that can suggest AIDS?
oral hairy leukoplakia
Where is a peridontal infection found and what are the types?
Infection of the soft tissue around the mouth
- Mild (gingivitis)
- Moderate (periodontitis)
- Severe (necrotising gingitivitis)
If parotitis is caused by bacteria i.e not mumps, what is the causative agent?
S.aureus
What are the two types of food borne GI diseases?
intoxication and infection
What are the differences between intoxication and infection in terms of:
- Transmission
- Incubation period
Intoxication:
- ingestion of pre-formed toxin
- rapid incubation period
- not communicable
Infection:
- ingestion of bacteria, virus or parasite
- slower incubation period
- person to person (faecal-oral)
What are the symptoms of an intoxication with a food bourne GI disease?
vomiting nausea diarrhoea weakness respiratory failure numbness sensory/motor dysfunction
Which factors contribute to intoxication with a food bourne GI disease?
inadequate cooking, improper handling temperatures
What are the symptoms of an infection with a food bourne GI disease?
diarrhoea nauseau vomiting abdo cramps fever
Which factors contribute to infection with a food bourne GI disease?
inadequate cooking, cross contamination, poor hygiene and handwashing procedures
What does intoxication food poisoning with S.aureus result in?
- it is a heat stable enterotoxin
- projectile vomiting and nausea
- no diarrhoea
How fast is the onset of S.aureus food poisoning?
4hrs after eating - fast
S.aureus food poisoning can result from eating what?
mayonnaise, meat, dairy products
Explain the features of food poisoning with B cereus?
Bacillus cereus I:
- vomiting
- no diarrhoea
- quick onset
Baccilus cereus II:
- little vomiting
- profuse diarrhoea
- 12-14 hours after eating
Eating what can result in B cereus food poisoning?
B cereus I:
-cooked rice and other starchy foods
B cereus II:
-wide variety of foods
What are the features of clostridium perfringes food poisoning and what foods is it associated with?
- abdominal cramps
- watery diarrhoea
- 1-4 hours after eating
- meat, meat products
What are the features of intoxication with clostridium botulinum?
- neurotoxin / botulism
- blurred vision, respiratory failure
- flaccid paralysis
- slow (1/2 days after eating)
Consuming what is associated with clostridium botulinum?
improperly canned food
What is infant botulism?
C.botulinum spores in honey can colonise infant (<1 yr) GI tract and produce toxin
-causes constipation, neurological symptoms but is a milder disease than in adults
Is salmonella toxin mediated?
no it is an infection
What are the effects of infection with salmonella food poisoning?
- cramps, diarrhoea, fever, myalgia
- nausea and vomiting
- onset 6-8 hours after eating
What is salmonella ssp found in?
poultry, birds and some reptiles
What is the most common type of salmonella?
S.enteritidis
How do you treat gastroenteritis caused by salmonella?
- antibiotic treatment is not recommended for health people with gastroenteritis due to salmonella infection
- consider antibiotic treatment if older than 50, immunocompromised or have vascular/valve disease
- if so, prescribe ciprofloxacin
What does dysentery mean?
an infection of the GI tract that causes diarrhoea containing blood or mucus
What are the effects of being infected with Shigella spp (dysentery)?
- watery, bloody, mucoid stool, abdo pain
- fluid, electrolyte loss
- 36-72hr incubation period
How can infection with Shigella spp occur?
guts of humans, primates, faecal oral route
What are the 3 types of shigellae on DCA?
S. dysenteriae - most severe
S.flexneri
S. sonei - most mild, common in UK
How do you treat gastroenteritis caused by Shigella?
Antibiotic treatment is not recommended for health people with mild shigellosis
Consider antibiotic treatment for people:
- With severe disease
- Who are immunocompromised
- With bloody diarrhoea
if so, ciprofloxacin
Explain the features of infection with campylobacter spp?
- watery diarrhoea
- nausea, vomiting, malaise, headache
- 2-5 day onset - slow
- toxin and infection
How do you become infected with campylobacter?
poultry, birds, faecal-oral route
How do you treat gastroenteritis caused by campylobacter?
- antibiotic not needed for mild symptoms
- fluid and electrolyte replacement may be needed
- antibiotics for: severe symptoms, immunocompromised, long course
- if so, erythromycin
What are the features of infection with E.coli 0157?
- watery diarrhoea, then bloody diarrhoea
- haemorrhagic colitis/ haemolytic uraemic syndrome in 10%
- 2-5 days onset - slow
- can acquire shigella toxin and produce haemorrhagic diarhoea
Infection with E.coli 0157 is associated with eating what?
cattle and meat
What are some complications of infection with E.coli 0157?
Acute renal failure, thrombocytopenia, microangiopathic haemolytic anaemia
How do you treat gastroenteritis caused by E.Coli 0157?
- all E.colis are self-limiting - don’t prescribe antibiotics
- treatment is supportive
What are some other less common causes of bacterial gastoenteritis?
- Yersinia enterocolitica
- Listeria monocytogenes – dangerous in pregnant women
- Vibrio parahaemolyticus – associated with shellfish
- Plesiomonas shigelloides
Name the 5 viruses that can cause gastroenteritis?
- Rotavirus
- Adenovirus
- Norwark/ norovirus
- Astrovirus
- Calicivirus
all effect children, norovirus, astrovirus and calicivirus can effects adults too
Amoebic dysentery: What are the effects of infection with entamoeba histolytica?
- watery then bloody diarrhoea
- N&V, tenesmus, malaise
- extra intestinal symptoms e.g liver abscesses
- very slow onset: 15 days
How is infection with entamoeba histolytica acquired?
contaminated food and water
How do you treat amoebic dysentry?
-antibiotics
What are the effects of infection with cryptosporidium parvus?
Cryptosporidiosis:
- watery diarrhoea, weight loss, fever
- severe chronic diarrhoea in immunocompromised
- v slow: 2-10 days
How is cryptosporidium parvum acquired?
found in fish, reptiles, animals and common water contaminant
How do you treat cryptosporidiosis?
no antibiotics unless immunocompromised
What are the features of giardia intestinalis?
Giardiasis:
- foul smelling, watery diarrhoea, cramps
- steatorrhoea, flatulence
- chronic relapsing diarrhoea in some
- 1-4 weeks but sudden onset
How do you become infected with giardia intestinalis?
common water contaminant
How do you treat gastroenteritis caused by Giardia intestinalis?
-antibiotics - metronidazole
What are the effects of infection with vibrio cholerae?
- abrupt, “rice water” stool
- significant fluid loss, hypervolemic shock
- 12hrs-5 days - slow
How is infection with vibrio cholerae acquired?
water or food borne (esp shellfish)
What are the different serotypes of cholera?
01 - classic cholera
Non-01 (0139) - milder disease
How do you treat cholera?
replacement of fluid loss
What are two organisms that cause enteric fevers?
- Salmonella typhi
2. Salmonella paratyphi
What are the features of enteric fever from salmonella?
-fever, headache, malaise, anorexia
-diarrhoea, splenomegaly, high fever, rose spots
slow onset
-high fatality if not treated
-can become a chronic carrier - “typhoid mary”
How do you treat enteric fever?
immediate antibiotic treatment - azithromycin
What are the effects of Clostridioides difficile, an antibiotic associated diarrhoea?
- foul smelling, watery diarrhoea, cramps, low grade fever
- can lead to PMC (pseumembranous collitis), toxic megacolon and death
What type of inflammation is C.diff?
toxin mediated - spores aid transmission
What are the risk factors for C.diff?
antibiotics, age> 65 yrs, hospital stay
How should you treat antibiotic associated diarrhoea?
stop predisposing antibiotic and start treatment with vancomycin
what complications can arise from streptococcus gallolyticus ?
infective endocarditis and septicaemia in elderly
strongly associated with colorectal cancer
