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Flashcards in Infectious Disease Deck (53):
1

What causes scarlet fever?

Streptococcus pyogenes

2

You are a surgical house officer and have been bleeped to see a 34 year old man who is post op day 1 following abdominal surgery. He complains of intense pain around his leg. On examination it is erythematous. His temperature is 38.3, HR 160, BP 135/96. He is a known diabetic and heavy drinker. What is the most appropriate management?

IV morphine and urgent referral for surgical debridement
This patient has necrotising fasciitis

3

What are risk factors for necrotising fasciitis?

Abdominal surgery
Diabetes
Alcoholism
Malignancy

4

What 4 drugs are used to treat TB?

Rifampicin
Isoniazid
Pyrazinamide
Ethambutol

5

What is a main side effect of ethambutol? What should be done before commencing treatment?

Toxic optic neuropathy
Test visual acuity and colour vision before treatment

6

What test should be performed prior to commencing rifampicin, isoniazid and pyrazinamide treatment?

LFTs as they can cause hepatitis

7

What type of bacteria is E.coli?

Gram negative bacilli

8

What is infectious mononucleosis?

Glandular fever
Self limiting infection due to Epstein Barr virus
Low grade fever, sore throat, lethargy

9

How do you diagnose glandular fever?

Monospot test

10

What happens if you prescribe amoxicillin to patients with glandular fever?

Severe rash

11

What is leptospirosis?

Weils disease
Infection caused by spirochaetes
Due to contact with infected urine, usually from rats
Mild flu like symptoms, jaundice, meningitis and renal failure in severe cases

12

How long after HIV exposure is post exposure prophylaxis effective for?

Most effective within an hour of infection
After 72 hours, effectiveness is very limited

13

What are the 3 most common chase of lung infection in people with cystic fibrosis?

Staph aureus
Haemophillus influenza
Pseudomonas aeruginosa: rusty coloured sputum

14

What sort of infections are people with a splenectomy susceptible to? And why

Encapsulated organisms for example h. Influenza and strep pneumoniae
Because spleen provides environment where encapsulated organisms are opsonised

15

What is antimicrobial stewardship?

Organisational approach to promoting and monitoring judicious use of antimicrobials to preserve their future effectiveness

16

What are the principles of antimicrobial stewardship?

How: Prescribe only when needed, Review need for abx in accordance with local formularies and guidelines
Why: Optimise therapy for individual patients, Prevent overuse, misuse, abuse, Minimise development of resistance at patient and
community levels

17

Who has responsibility for antimicrobial stewardship?

Clinicians
Society: Demand and supply
Politicians
Corporations

18

Why is antimicrobial stewardship important?

Optimise therapy for individual patients
Minimise side effects
Microbiome: all antibiotics, limit with narrower spectrum
Allergy and intolerance, specific contraindications and interactions
Prevent overuse, misuse, abuse
Minimise development of resistance at patient and community levels

19

How can we limit the need for antimicrobials?

Prevention and control of infection: No infection means no antibiotic needed, No multi-resistant organism means narrower spectrum antibiotic can be used

20

List resources available to aid optimal antimicrobial prescribing

TARGET antibiotics toolkit: treat antibiotics responsibly guidance, education and tools
NICE guidelines
Department of health antimicrobial stewardship guide
Local primary and secondary care guidance

21

What is contained in the TARGET toolkit?

Commissioner resources
Information for patients
Audit tools
Training resources
Self assessment
National antibiotic management guidance

22

List the principal considerations required before commencing antibiotic therapy

Absorption (How can I get it into my patient?)
Distribution (does it get where I want it to?)
Predictably sensitive? (is resistance likely to be a problem before or after treatment?)
Adverse effects (common, particular patient group?)
Interaction with other drugs (prescribed or otherwise)
Metabolism and excretion (how does the drug get out? Is that a problem in my patient?)

23

What are beta lactam antibiotics?

Penicillins and their derivatives
Cephalosporins (ceph/ cef….)
Carbapenems (-penems)
Monobactams (aztreonam)

24

Describe the absorption profiles of the beta lactam antibiotics

Penicillins: Penicillin V/ phenoxymethylpenicillin low absorption from GI tract, Amoxicillin better, Penicillin G/ benzylpenicillin no absorption so given IV
Cephalosporins: Limited number available orally, generally good absorption for those that are (cefalexin), Most IV only e.g. ceftriaxone
Carbapenems: No oral formulation
Aztreonam: Also IV only

25

Describe the distribution profile of beta lactam antibiotics

Generally good penetration to body tissues
Penicillins don’t cross the blood-brain barrier well unless the meninges are inflamed
Do not get inside individual host cells
Poor activity against bacteria that live intracellularly, Legionella is classic example

26

Describe the mechanism of action of beta lactam antibiotics. What implication does this have?

Interruption of cell wall synthesis
So NO activity against bacteria without a cell wall (Mycoplasma, Chlamydia)

27

What is the difference between a bacteriostatic and bacteriocidal antibiotics?

Bacteriostatic: inhibiting the growth of a bacterium
Bactericidal: killing the bacterium

28

What is the minimum inhibitory concentration?

Lowest concentration of an antibiotic which inhibits visible growth of bacteria

29

What is minimum Bactericidal concentration?

Lowest Concentration of an antibiotic that kills 99.9% of a population of bacteria

30

What is the breakpoint in terms of antibiotic sensitivity?

Minimum inhibitory concentration cut-off which separates strains where there is a high likelihood of treatment succeeding from those where treatment is more likely to fail

31

How does resistance to beta lactams occur?

Intrinsic: No cell wall, Strictly intracellular bacteria, No target for the specific drug
Acquired: Stop the drug getting in, Break it down, Change the target, Pump it out

32

Describe the forms of acquired antibiotic resistance that occurs with beta lactams and what can be done about this

Enzyme which breaks the antibiotic down (e.g. Staphylococcal penicillinase), use an enzyme inhibitor to restore susceptibility (co-amoxiclav)
Alteration in target site (e.g. MRSA), need to find a new target for a different antimicrobial

33

What are some adverse effects of beta lactam antibiotics?

Generally safe and well-tolerated: low rates renal of hepatotoxicity, neurotoxicity, Jaundice with flucloxacillin and co-amoxiclav
Diarrhoea with any, especially broad spectrum (C difficile particular association with cephalosporins)
IgE-mediated allergy in 5-10% patients

34

Are beta lactam antibiotics teratogenic?

No

35

Which drugs might interact with beta lactams?

Anticoagulants
Oral contraceptive (not contraindicated)
Anti-epileptics

36

How are beta lactams excreted?

In urine
Excretion rates very rapid for older penicillins, so need to be given frequently
4-hourly for benzylpenicillin in severe infection
Pencillin V given qds

37

At what level of renal function do you need to adjust the dose of beta lactams?

Only in very poor renal function
GFR less than 10

38

What are potential complications of meningococcal disease?

Septic shock
Hypotension
Acidosis
DIC
Hearing loss
Motor and cognitive disability
Blindness
Ischaemic injury to skin/extremities

39

What is Waterhouse friderichsens syndrome?

Bilateral adrenal haemorrhage typically caused by fulminant meningococcal infection

40

What are risk factors for the development of meningococcal disease?

Young age
Complement deficiency
Asplenia or hyposplenia
Residence in dormitory
Globulin deficiency
Close contact with invasive meningococcal infection
Household crowding
Travel to endemic area
Lab worker

41

What are risk factors for toxic shock syndrome?

Diabetes mellitus
Alcoholism
Trauma
Surgical procedures, particularly vaginal delivery, c section, hysterectomy
Single tampon use for consecutive days
Highly absorbent tampons

42

What are potential complications of toxic shock syndrome?

Bacteraemia
Acute respiratory distress syndrome
DIC
Renal failure
Waterhouse friderichsen syndrome
Wound sequelae requiring major surgery

43

How many days pen V should be prescribed for streptococcal sore throat?

10 days

44

A 23 year old with fever sore throat and swollen neck and groin nodes, what is the most likely diagnosis?

Glandular fever

45

What is the test for glandular fever?

Monospot
Paul Bunnell

46

A mum brings a 4 year old boy to GP with right earache and fever for 24 hours. This morning it has started to discharge pus, what is the most likely diagnosis?

Otitis media with perforation

47

What tests can be done for streptococcal infection?

ASOT - antistreptolysin O titre
Anti DNAase B titre

48

What can cause laryngitis?

Complication of URTI
Parainfluenza
Measles

49

What should be done to treat acute laryngotracheobronchitis?

Nebulised adrenaline
Oral/IM corticosteroids
Oxygen
Fluids

50

What should be done to treat acute epiglottitis?

Endotracheal intubation
IV ceftazidime

51

In which patients is an inflenza vaccine recommended?

Over 65s
CHD
Lung disease
CKD
Diabetes
Immunosuppressed

52

How do you treat sinusitis?

Nasal decongestant
Co amoxiclav
Fluticasone proprionate (corticosteroid) nasal spray
Steam inhalation

53

What do you do to manage recurrent sinusitis or if there is an orbital cellulitis complication?

Refer to ENT for CT of paranasal sinuses