Management of common infections Flashcards
1
Q
What is antimicrobial stewardship
A
- Sensible antibiotic prescribing
2
Q
Why is antimicrobial stewardship important
A
- Antibiotic resistance
- Antibiotic adverse effects
- Antibiotic costs and the costs of side effects
3
Q
Why has antimicrobial resistance arisen
A
- Injudicious use of antibiotics in the hospitals, community and agriculture
- Inherent property of micro-organisms – promiscuous and inherent
- Understandable lack of investment for pharmacology
4
Q
how many people suffer side effects due to antibiotic adverse reactions
A
- 20% of patients will suffer harm due to antibiotics
- Includes allergy, side effects C.diff etc
5
Q
why do antibiotic side effects cost money
A
- Increased referral to secondary care
- Increased length of in secondary care
- Increased treatment and investigation cost
Delayed return to work
1 episode of C diff costs
- UK £3000
- France 7000 euros
- USA $34,000
6
Q
How can you make change in prescribing antibiotics
A
1, be convinced to the importance of antibiotic resistance
2, be convinced that your responsible antibiotic use can contribute to controlling resistance
3, have the confidence, motivation and tools to use antibiotics responsibly
7
Q
What are the principles of infection management
A
- Pus
- Agent, dose, route, duration
- Allergy
- Guidelines
8
Q
What are the other things that can be like an infection
A
- Fever and elevated CRP infection – does not always mean infection, it can mean inflammation
- Pancreatitis
- Drug fever
- Malignancy
- Blood in the wrong place: thrombus or haemorrhage
9
Q
when prescribing antibiotics what is it important to
A
- Decent samples – pus as opposed to swabs
- Colonisation and normal flora compared to infection and dangerous microorganisms
- Proper labelling of samples – is it from a sterile site, same bug may mean very different things
10
Q
What does Ubi pus Ibi evacua
A
- Where there is pus let it out – if there is a big bag of pus antibiotics will find it difficult to penetrate into that absesce therefore you should let it out
- Also applies to a foreign body – remove it
- Or if there is non-viable tissue – debridge it
11
Q
What are the downside of antibiotics
A
- have limited capacity to penetrate an abscess cavity
- Altered biochemistry within an abscess can inhibit antibiotic activity – pH and anaerobiasis
- Sheer number of bacteria
12
Q
when deciding to prescribing an antibiotic the prescription should include…
A
- The right agent based on the suspected/prove indication and microorganisms
- At the right dose
- Right route
- And for the right length of time
13
Q
What does the antibiotic prescription depend on
A
- Does the antibiotic get where it needs – for example does it cross the blood brain barrier
- Is there positive microbiology – no empirical, yes = directed
- How sick is the patient?
- Does the patient have any allergies or intolerances?
14
Q
What does the right dose depend on
A
Infection factors
- Organisms
- Anatomical location
- Severity
Patient factors
- Age
- Pregnancy
- Renal function
- Liver function
- Other medicies and interactions
15
Q
What is the right route
A
IV
- Ensure large doses that cannot be taken orally
- Ideal anti-infective only comes in IV form
- Patient GI route is compromised
16
Q
What are the IV risks
A
- Usually related to the IV cannula
- Usually more expensive
17
Q
What are antibiotics with reliable absorption
A
Clarithromycin Clindamycin Ciprofloxacin & other quinolones Doxycycline Metronidazole Rifampicin (if given pre-food) Fucidic acid (if give pre-food) Cotrimoxazole (Septrin) - Penicillin’s are more variable absorption
18
Q
What is the right length of time
A
- Evidence free zone – not sure
19
Q
How do you detect bacteria
A
Clinical – fever and appetite
Biochemical – CRP, WBC, platelets
Radiological – useful but changes can lag
20
Q
What to do if the bacteria is not responding to the antibiotic
A
- Right antibiotic – is it active against what you want to treat
- Think about resistance – re culture and get more samples
- Is it the right dose and via the right route
- Has source control been achieved – removed the bulk of infection for example drain pus and remove prosthesis
- Is the problem caused by an infection?
21
Q
Does combination work in antibiotics
A
- Two antibiotics is not always better than one, some may be antagonistic, and can cause compound toxicity
22
Q
What are instances where antibiotic combination therapy is useful
A
- Empirical antibiotics – to cover more bases
- For synergy – e.g. low dose agent in streptocoocal IE
- To prevent resistance – TB, HIV, S,auresus
- Mixed infection – where 1 agent doesn’t cover all bases
23
Q
why should you know the difference between allergy and intolerance of antibiotics
A
- > 10% of population think they are allergic to penicillin and only a fraction have arue allergy
- For some infection giving another agent that is not penicillin is less effective and results in worse outcomes
24
Q
what does a type 1 reaction - immediate hypersensitivity look like
A
- Skin
- Resp
- GI
- CVS
Itch, rash (urticarial), swelling wheeze -> stridor
pain, vomiting, diarrhoea hypotension
AVOID RE-CHALLENGE - typically within minutes - can be up to two hours
25
what does an intolerance to antibiotics look like
- Gastrointestinal upset
- Headache
- Odd taste
- onset usually after several doses/days
26
How can you manage the side effects of antibiotics
```
- Can try and manage side effects for example nausea with antiemetics
Not always cross class effect – e.g. diarrhoea from erythromycin > clarithromycin
```
27
why do people have a penicillin allergy
- Penicillin allergy is very common – beta lactams
- Penicillin and its derivatives have a common structure – the beta lactam ring
- IgE may be directed to the beta lactam ring or side chains – determines range of agents patients may be allergic to
28
What is diagnostic stewardship
- Processes involved in the lab – should we work up that isolate, how much work should we do, what is the significance of the result commensal v pathogen
29
How can diagnostic stewardship lead to harm
- Need to ask is this test necessary, can it answer the question im asking
- Need to consider all stages – samples and clinical info coming into the lab, process within the lab, results and accompanying information
30
What is pyrexia of unknown origin
Fever, the cause of which remains unknown despite
- History and examination
- Blood cultures – 3 sets, 3 sites, several hours between and urinalysis
- Routine: FBC, U&E, LFT
- CXR
- Further tests if any localising symptoms/signs
31
What are the causes of pyrexia of unknown origin
- Infections
- Malignancies
- Connective tissue disease such as vasculitis, rheumatoid arthritis
32
what does the frequency of causes of pyrexia of unknown origin vary with
- Age
- Geography/travel
- Presence/absence of immunosuppression
33
list examples of pyrexia of unknown origin
Infection
- TB
- endocarditis
- Abscess
- Teeth, sinuses and back
- Infected prosthesis
- typhoid
- EBV, CMV, HIV
rheumatological
- Adult onset Still's
- giant cell arteritis
- Vasculitis
- cryoglobulinaemia
- periodic fever syndromes
Malignancy
- lymphoma
- revel cell carcinoma
- hepatocellular carcinoma
mEDICATION
- Antibitoics
- Anticonvulsants
- NSAIDS
- antihypertensives
- antihistamines
- ETOH - alcoholic hepatitis
- recreational
34
whats important in a history of unknown pyrexia origin
- Travel
- Immunosuppression
- Contacts
- Drug history
- Localising symptoms
35
what tests should you do in a history of unknown pyrexia
ESR, CRP, LDH, ferritin, CK, TFT, blood film (including malaria)
RhF, ANA, dsDNA, C3 & C4, cryoglobulins
Serum protein electrophoresis & serum free light chains
Serology: HIV, HBV, HCV, syphilis, EBV, CMV, serum-save etc
Imaging: CT / PET-CT / echocardiography
Biopsy, bone marrow
36
What can be the cause of a UTI
- Infection of the urinary tract by organsism that normally reside in the GI tract
37
Who does a UTI need treating in
- Immunosuppressed
- Abnormal anatomy of urinary tract
- Children
- Pregnancy – 30% chance of developing pyelonephritis
38
what is proteus associated with
- Strongly associated with renal calculi
- - Breaks down urea> ammonia>alkaline urine>stones
- If you see an MSU growing proteus consider imaging
39
What happens if S aureus in the urine
- Not a typical uropathogen – look for endocartitis
| - Renal absecess -> urine
40
what happens with nitrofuranotonin
- Check renal function before advising – it wont get into the urine if eGFR < 60ml/min
41
what does pyelonephritis cause
- Causes prolnged fever
- Median time to fever settling in pyelo is 3-4 days
- Persistence of fever does not = renal failure or need for stronger antibitoics
- If patient improving then carry on
42
what do you need further investigations for in a UTI
- UTI in a child
- UTI in a man
- Recurrent
- Persistant symptoms despite antibiotics
