Gastroenteritis - nathwani Flashcards
what is gastroenteritis?
Inflammation of stomach or intestines
Inhibits nutrient absorption and excessive H2O and electrolyte loss
what are the causes of gastroenteritis?
- mainly infection (bacteria, parasites, viruses - majority, and microbial toxins)
what are the core clinical problems of gastroenteritis (3)
- fever
- abdo pain
- diarrhoea ± blood
microbial toxins may be ____-____ or __ ___-
pre-formed or in vivo
which organisms pre-form toxins?
staph aureus, clostridium perfringens or bacillus cereus
which organisms form toxins in vivo
Vibrio, enterotoxigenic E.coli
what is the onset time for microbial toxin causing gastroenteritis?
1-6 hours
diarrhoea > few hours , abdo pain and afebrile
with microbial toxin causing gastroenteritis there is no ___ or ___ in the faeces
no blood or pus
how long does it take for microbial toxin causing gastroenteritis to resolve?
1-6 hours
treatment with ____ ____ has a role in the emergence of gastroenteritis
acid suppression
what are some causes of non-infectious diarrhoea? 7
GI bleed Ischemic gut Diverticulitis Endocrine disorders Numerous drugs Fish Toxins Withdrawal
the approach to any clinical infection syndrome!!!
- What are the key clinical symptoms and signs that suggest the infection?
- Differential diagnosis
- Severity of Infection
- Site and microbiological diagnosis: investigations
- Antibiotic and supportive management
- Infection Control
- Public Health
what organism causes the most gastroenteritis
norovirus
norovirus occurs in ___ ___ or ____ and is a cause of community wide ____
older children, adults, outbreaks
what makes norovirus so infectious?
the virus is ejected in vomit and it has aerosol transmission
viruses have a ____ incubation period than bacteria
shorter
what is the incubation period for norovirus?
24- 48 hours
what are the three presenting clinical syndromes of food poisening
- Acute enteritis : fever. D&V, abdominal pain
- Acute colitis: fever, pain, bloody diarrhoea
- Enteric fever like illness : fever, rigors, pain but little diarrhoea - around 10 % of patients will have this
differential diagnosis of bloody diarrhoea
infection - usually indicates colonic inflammation
IBD
Malignancy
Ischaemia
which organisms cause bloody diarrhoea?
- campylobacter
- shigella
E.coli 0157 - amoebiases
campylobacter infection is closely related to meals with ___
chicken
incubation period for campylobacter: __-___ days
2-5 days
what is a common misdiagnosis of campylobacter?
appendicitis
____ ___ is a rare but IMPORTANT COMPLICATION of camplyobacter
guillian barr
how long does campylobacter last
5-14 days
treatment for campylobacter is ____ however in severe cases may be treated with _____ or ____
supportive, clarithromycin or azithromycin
what is guilllian barr syndrome symptoms?
Tingling of the feet leads to progressive paralysis of the legs, arms and rest of the body
the stool exam for leukocytes -erythrocytes is ____ for campylobacter
positive
what may you see on X-ray with gastritis?
thumbprinting - usually caused by oedema, related to an infective or inflammatory process (colitis)
what happens in thumbprinting?
the normal haustra become thickened at regular intervals appearing like thumbprints projecting into the aerated lumen
someone presents with fever, they are systemically unwell and have rigors and abdo pain.
They had short history of diarrhoea 1 month ago, what is this?
enteric fever like illness
____ ___ is an enteric fever
typhoid fever
_____ is Almost always imported (Indian subcontinent, SE Asia, Far East, Middle East, Africa, Central/
South America)
typhoid
what are the carriers of typhoid?
primarily food but can be water
what are the symptoms of typhoid? 4
Asymptomatic, mild, bacteraemia, enterocolitis
what is the key to diagnosis with typhoid?
blood cultures,
then stool and urine cultures
what antibiotics are given for typhoid?
chloramphenicol and ciprofloxacin, ceftriaxone or azithromycin
there is a vaccine for ___ but it is only __% effective and is not effective against ______ strains
typhoid, 70%, paratyphoid
what are the key features in the history
diarrhoea
associated symptoms: abdo pain, vomiting, fever, urgency, incontinence
anyone in family or work with similar symptoms
occupation
pets and ANIMAL CONTACT
Travel
Drug history - particularly PPI or antibiotics
what do you want to know about the diarrhoea?
- frequency
- nocturnal - generally pathological
- colour and consistency
- presence of blood
what are the key features of examination?
- fever
- skin rashes
- dehydration: BP, postural drop, pulse
- abdominal tenderness, distension
- rectal examination: stool, blood, tenderness
what rashes may appear?
rose spots, erythema nodosum
what are signs of dehydration
pulse, mental state, dry tongue, skin turgor
what are the options for tests? 6
STOOL:
- microscopy
- culture
- toxin
BLOOD CULTURES
PCR
FBC
Us and Es
AXR
when do you do microscopy?
if parasite
e.g history of travel for giardia, amoeba etc
when would you do a culture?
Salmonella, Campylobacter, Shigella suspected
when would you do a toxin?
c.diff
_____ test for E.coli 0157
cytotoxin
why do renal tests?
need to know if they are dehydrated
factors in assessment of severity?
there are lots but:
Colonic dilatation- from AXR
laboratory : WCC, renal function
these are important, were bold in the lecture
Severity of C.diff : one or more of the following severity markers for treatment to be classed as severe not mild (note treatment options differ for mild and severe)
- Suspicion of ________ _____ (PMC) or ___ -___ or ____or ___ ____ in CT/AXR >6cm
- WCC >__ cells/mm3
- Creatinine >___ x baseline
- Persisting symptomatic CDI despite __ treatments
- Suspicion of Pseudomembranous colitis (PMC) or toxic megacolon or ileus or colonic dilatation in CT/AXR >6cm
- WCC >15 cells/mm3
- Creatinine >1.5 x baseline
- Persisting symptomatic CDI despite 2 treatments
what are the complications of Bacterial Enteritis? Intestinal - 4
- severe dehydration and renal failure
- acute colitis, toxic dilatation
- post infective irritable bowel (very common)
- transient secondary lactase intolerance
what are the complications of Bacterial Enteritis? extra-intestinal - 6
- Bacteriaemia leading to sepsis
- Reactive arthritis
- Meningism
- Neurological [Guillian Barre syndrome]
- Haemolytic uraemic syndrome
what metastatic infections can you get if you are bacteraemic? and what else can occur in sepsis?
metastatic infection: meningitis, aortitis.
Ostyeomyelitis, endocarditis
______ from ____ causes the haemolytic uraemic syndrome
toxin from e.coli 0157
why do we give antibiotics therapy ? 3 reasons
To prevent and treat invasive disease especially in immunocompromised patients
To reduce the severity and duration of symptoms
To eradicate faecal excretion in order to reduce environmental contamination and to limit the spread of infection in the community
how is gastritis generally treated?
supportive therapy :
Oral rehydration
Intravenous fluids (saline important) if very unwell
may need antibiotics - only in specific situations though
what are the indications for antibiotics? which bugs? 8
- Enteric fever [TYPHOID]
- Shigellosis [non sonnei species]
- Enterotoxigenic E coli [SOMETIMES]
- Cholera
- Clostridium difficile diarrhoea
- Giardiasis
- Amoediasis
- Invasive salmonellosis
Does the patient need admitted to ID unit? (eg ____, ____)
Does the patient need admitted to ID unit? (eg Salmonella, E coli O157)
which bugs have a low infectious dose?
viruses, E.coi
what are some other infections spread by faecal-oral route?
hep A and E
Resistant bacteria that are carried in the GI tract, e.g vancomycin-resistant enterococci, highly resistant Gram negative organisms (CPEs)
