Elderly Medicine Flashcards
Why might a stool sample be useful in investigating GI infection?
- microscopy, culture & sensitivity
- clostridium difficile screening
- virology
- to look for ova, cysts and parasites
When might abdominal USS and CT abdomen be performed when investigating GI infection?
Abdominal USS:
- this is the primary imaging technique when biliary infection is suspected
CT abdomen:
- this is the imaging technique of choice when other causes of intra-abdominal infection are suspected
- e.g. abscess, diverticulitis
What are sterile site samples?
Why might these be performed?
- collection of fluid or tissue from deeper sources of infection
- MC&S of intra-abdominal fluid should be completed when possible to guide antimicrobial therapy
- samples are taken directly from the site of infection at the time of the intervention
- samples are more likely to represent the “true” pathogen
What are drain samples?
What is the problem when interpreting these samples?
- involves taking fluid from drains that have been placed previously, typically from collecting bags
- results must be interpreted with caution as they may represent colonisation of the drain and not the “true” pathogen
- this is a non-sterile sample
What would the diagnosis be in this scenario?
What antibiotics would be started?
- acute bacterial gastroenteritis - campylobacteriosis
- you would NOT want to start antibiotics as the patient is not in a high risk group
After identifying a case of acute bacterial gastroenteritis in the patient who should be notified?
Does the patient need to be put into source isolation?
- PHE should be notified when any new case of food poisoning is found
- This could be a sporadic case or it could be part of an outbreak that you are unaware of
- the patient is from a long-term care facility and there may be potential implications in food handling at that premises
- it depends on local policy, but this patient will probably not be put into source isolation as direct person-to-person spread is rare, especially if the patient is continent
What is the definition of acute gastroenteritis (food poisoning)?
What typically causes it and what accompanying symptoms may be present?
- an illness of < 14 days duration characterised by the presence of diarrhoea
- this means there are 3 or more loose stools per day or bloody stools
- accompanying symptoms may be abdominal pain / cramps, nausea, vomiting and fever
- typically a self-limiting illness
- it is usually caused by ingestion of food or water contaminated by GI flora
What pathogens are associated with causing acute gastroenteritis?
- Campylobacter spp.
- Salmonella spp.
- Shigella spp.
- certain strands of E. coli, viral and protozoans
What are the risk factors for acute gastroenteritis?
- increasing age > 60 or age < 5 years old
- eating raw or undercooked foods
- farmers or workers in the meat industry
- foreign travel
- eating out
When is antibiotic treatment recommended for acute gastroenteritis?
- only for patients who can develop complications from acute gastroenteritis
- this includes pregnant women, those on immunosuppression therapy and those with symptoms lasting over a week
- most other patients have no adverse consequences and derive no benefit from antibiotic therapy, so treatment is NOT recommended
How should acute gastroenteritis be reported?
What advice is given to patients?
- cases of infective gastroenteritis should be reported to PHE, particularly those involving food handlers
- highlight the importance of hand hygiene, food hygiene and disinfection of bedding
What is the diagnosis?
How is this diagnosis made?
Clostridium difficile infection
- diagnosis is made by the presence of loose stools (type 5 - 7) and positive Clostridium difficile test or clinical suspicion while awaiting confirmatory tests
- things that raise clinical suspicion in this case:
- long course of ciprofloxacin
- description of the stools - green, slimy and offensive smelling
- accompanied with fever
How would you confirm the presence of Clostridium difficile?
- take a stool sample for “Clostridium difficile testing”, which involves:
-
GDH (glutamate dehydrogenase) screen to determine if clostridia are present
- this does not tell you whether the clostridia present are producing toxins
- clostridia are present in many asymptomatic people
- cytotoxin assay to determine if toxin is actively being produced
- if both GDH screen and cytotoxin assay are positive, then clostridium difficile infection can be diagnosed
-
PCR for toxin genes may be performed to determine if toxin genes are present
- this shows the ability to produce toxin in the future, even if it is not currently being produced
- this patient might be at risk of future C diff diarrhoea so might want to consider rationing antibiotics
What other investigations might be performed in someone with suspected C diff infection?
- FBC, U&Es, LFTs and lactate
-
abdominal X-ray and/or CT abdomen to look for colitis in more severe disease
- e.g. distension of the bowel or toxic megacolon
- these are only performed if there are abdominal clinical signs e.g. stomach cramps
What factors predispose to developing C diff infection?
- old age (> 65 years)
- being in hospital
-
previous antimicrobial therapy
- especially 2nd (e.g. cefuroxime) and 3rd (e.g. cefotaxime) generation cephalosporins
- co-amoxiclav
- clindamycin
- quinolones (e.g. ciprofloxacin)
- long duration of antibiotic use (> 7 days)
- multiple antibiotic courses
- severe underlying disease
- presence of nasogastric tube
- non-surgical gastrointestinal procedures
- proton pump inhibitors
What is involved in the non-antimicrobial management of someone with C diff infection?
- fluid resuscitation and electrolyte replacement as appropriate
- immediate instigation of isolation policy and clostridium difficile Infection Control Policy
- review ALL antimicrobials and any medicines that can produce diarrhoea
- record stool frequency and consistency daily on a Bristol Stool Chart
- daily monitoring for signs of increasing severity of disease
- review and stop PPIs if appropriate
- dietetic input and review in patients with a malnutrition universal screening tool score of 2 or more
When should treatment for C diff infection be started?
What is involved in the antimicrobial management of C diff infection?
- treatment should be started if clinical suspicion is high, while awaiting toxin result
- the choice of antimicrobial depends on severity of disease, the number of co-morbidities and the number of episodes of CDI
- PO Vancomycin or PO Fidaxomicin are used
- PO metronidazole is less commonly used as it has been shown to be less effective
What are the indications for using oral vancomycin?
Why is IV vancomycin usually used?
- it is only indicated in non-severe to life-threatening Clostridium difficile infection
- when given orally, it only works in the intestines and is NOT absorbed
- IV vancomycin is used to treat a variety of infections
What is the mode of action of oral vancomycin?
it inhibits cell wall synthesis in gram positive bacteria
What is the diagnosis here?
How can you tell?
cholecystitis
- this is inflammation of the gallbladder
- diagnosis can be made from clinical signs:
- jaundice / scleral itcerus
- fever
- RUQ guarding / pain
- Murphy’s sign positive
What would the diagnosis be in this situation?
Why would you be concerned about the recent MSU results?
complicated acute diverticulitis
- this is acute diverticulitis accompanied by an abscess, fistula, bowel obstruction or perforation
- there are 2 MDR organisms in the urine, which indicates their presence in the colon of this patient
