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Flashcards in Revision gems Deck (59)
1

What is the cause of the hypervirulent C difficile strain?
ribotype 027

Mutation in tcdc gene--> binary toxin that usually downregulates other toxins is mutated-->increased production of toxins A and B

Diagnosed through standard tests.

2

Hypervirulent c diff has what clinical implications?

increased complications, mortality, and relapse
associated with fluroquinolone resistance.

3

What does severe C diff look like?

No diarrhoea, shocked, high WCC, ileus, low albumin
Megacolon and perforation at end stage
May have paucity of signs

4

C diff outbreak control- what works?

Infection control does not work
Antibiotic control does work- restrick FQ, cephalosporins
early and rapid diagnosis

5

C diff looks like what type of bug...

gram positive spore forming rod

6

C diff treatment?

Stop inciting abx if possible/lower spectrum abx
metronidazole orally
vanc orally
In relapsed cases, use the drug you have just failed with!!!
Second relapse, tapering and pulsed oral vanc
Third relapse: vanc and rifamixin
If so sick can't have PO- can give IV due to biliary excretion, NGT if surgeons allow, or retention enema
IVIG has been used
Surgery if near perforation
probiotics for treatment not that effective but some people use as an adjunct to therapy
NOTE THE TOXIN CAN BE DETECTED FOR WEEKS DESPITE SUCCESSFUL TREATMENT
Faecal microbiota therapy- deliver via NGT or colonoscopy

7

2/3 deaths in late HAART era are from...

non AIDS related illnesses
cancer
HCV
CV disease- theory of immune activation secondary to first few weeks of gut peyers patches breakdown after infection

8

Which HIV drugs can get into the CNS?

Abacavir (NRTI)
Nevirapine, delaviridine (NNRTI)
Kaletra, indinavir-rit, fosamprenavir-rit (PI)
(But no study currently re:prevention of neurocognitive impairment if commence therapy early- observational data only)

9

Where does HIV rank as an independent risk factor?

Not as high as smoking

10

Which HAART is the worst for cardiovascular risk?

Abacavir and the protease inhibitors

11

When do you start HAART?

Any CD4 count.
Other concept is community viral load and reduction of transmission ?ongoing high risk behaviour ?couple not seromatched
Though evidence less strong (3B) for CD4 count over 500

12

What are the implications of a lower CD4 count when starting HART

Marked benefit if start over 350- mortality implications, will not make it up to a higher CD4 count
SMART study is a prospective study enrolling those over 500
Especially important if pregnant, HBV, HCV, nephropathy

13

Pneumonia in an alcoholic... think?

Klebsiella

14

Lymphogranuloma venerum is secondary to what?

Chlamydia trachomatis

15

Stages of lymphogranuloma venerum ?
(3)

And how do you treat?

1. small PAINLESS pustule which later forms an ulcer
2. Painful bilateral inguinal lymphadenopathy
3. Proctocolitis

Tx is doxycycline

16

Causes of a painful genital ulcer?

Becet's
Herpes
Chancroid (unilateral painful inguinal LN, sharply defined and ragged edges, tropical disease caused by haemophilus ducreyi)

17

Causes of a painless genital ulcer?

Syphilis
Lymphogranuloma venerum
Carcinoma
Granuloma inguinale (secondary to klebsiella granulomatis)

18

What are the alpha haemolytic streps?

alpha = PARTIAL haemolysis
Looks green on the plate

S viridans
S pneumoniae

19

What are the beta haemolytic streps?

complete haemolysis meaning looks clear on plate

Groups A-H but ABD are the only ones clinically relevant

A= S pyogenes (erythrogenic, toxins cause scarlett fever. Impetigo, erysepilas, cellulitis, phar, tonsilitis, post S GN, rheumatic fever)
B= S agalactiae
D= enterococcus

20

What things do you do to prevent CVC infection?

Educate and trainig staff
Sterile insertion
Chlorhex skin prep
Daily review if needed
antibiotic impregnated catheters if still high rates (not part of the "bundle" they talk about from NEJM)
NOT antibiotic "locks"

21

What do the toxins A and B from C diff actually do?

Toxin A is an enterotoxin specific for CHO intestinal receptors

Toxin B is an cytotoxin that disrupts cellular tight junctions

22

What would be your treatment for carbapenem resistant enterobacteriacae?

eg E coli, Klebsiella, Salmonella, Shigella, Enterobacter

Infection prevention precautions

Treatment:
-combination regimens
-colistin
-Infusion carbapenem if low MIC (4-8_
-Tigecycline
-Fosfomycin (oral agent if need outpatient care)

23

Who gets PEP for varicella?

Immunocompromised - VZIG if less than 96 hours, also give aciclovir but limited evidence

24

Legionella is found in what sources?

L longbechiae- potting mix
L pneumophilia- humidifiers, cooling towers

25

Legionella clinical picture

Fever called "pontiac fever" - flu like
pneumonia
Renal impairment
Abnormal LFTs
Hyponatraemia
Raised CK

26

Legionella treatment

Macrolide
Cipro

27

leptospirosis happens in what group of people? (It is a spirochette!)

Farmers, abbotoir workers
Get it from cattle, pigs, rodents especially after rain via skin cuts or abrasions
Also participation in recreational water sports

28

What does leptospirosis look like clinically?

Mild self limiting usually
Sometimes hyperbilirubinaemia/jaundice , AKI, pulm haemorrhage, conjunctival haemorrhages

Bipahsic illness- early then late an immune mediated illness

Treat with penicillin and doxy- improve symptoms and complications but not mortality.

29

Melioidosis is caused by what?

Burkholderia pseudomallei

Gram negative rod, soil saprophyte

30

Clinically what does melioid look like?

Pneumonia, abscesses of SPLEEN and PROSTATE
Osteomyelitis, septic arthritis
Skin and soft tissue infection

HIGH MORTALITY WITH SEPSIS
Relapses common so long term eradication therapy needed

31

How do you manage melioid?

Ceftazidime, carbapenem
GCSF in septicaemia

32

EBV is associated with what cancers?

Burkitt's lymphoma (Chromosome 8 translocation and deregulation of c-MYC oncogene)
Nasopharyngeal carcinoma
HL
NHL ONLY IN IMMUNOCOMPROMISED

33

HHV8 is associated with what cancers?

Kaposi's sarcoma
Primary effusion lymphoma
Multicentric castlemans disease

34

HTLV-1 is associated with which pneumonia?

Adult T cell leukaemia

35

Opisthochis viverrini and Chonorchis sinensis are associated with what cancer?

CholangioCa

36

What is the clinical picture in Whipples disease?

Migratory large joint arthralgias
Weight loss and diarrhoea, abdo pain
Dementia, eye signs
Culture negative endocarditis, pleural effusion

Dx via small bowel biopsy or PCR

Tx is ceftriaxone then long term bactrim

37

What does HHV-6 do in immunosupression and how is it transmitted?

Transmitted in saliva
In transplant causes pneumonitis, hepatitis, encephalitis, bone marrow suppression or graft rejection, fever (reactivation around day 17)

38

How does botulism work?

Toxins A B E bind to pre-synaptic nerves and prevent release of ACh

Cranial nerves then symmetrical descent

Check food, EMG

Treat supportive + antitoxin and penicillin

39

Overwhelming post splenectomy infection- what is the empirical treatment?

Ceftriaxone and vancomycin

40

Empirical treatment for suspected IE?

Gent
Benpen
Fluclox

41

Does entamoeba cause eosinophilia?

No

42

H1N1 list of factors in order risk of hospitalisation, and risk of death.

Hospitalisation: Immunocompromise, obesity, pregnancy
Death: Obesity, Immunocompromise, renal failure, death

43

Gram stain CSF:
Gram positive cocci

S pneumoniae-->vanc and ceftriaxone
S aureus (if neurosurg or head trauma within one month)-->vanc

44

Gram stain CSF:
Gram neg cocci

N meningitidis

Ceftriaxone

45

Gram stain CSF:
Gram positive bacilli

Listeria

Penicillin G or ampicillin

46

Gram stain CSF:
Gram neg bacilli

Klebsiella or E coli-->ceftriaxone
Pseudomonas or acinetobacter if neurosurg last month or a neurosurgical device: ceftazidime, cefepime or meropenem

47

What medications can cause a drug related fever?

Carbamazepine
Phenytoin
Antimicrobials
Allopurinol
Heparin

Look for relative BRADYCARDIA- only seen in 10% but can be a clue to drug fever

48

What defines MRSA?

Presence of the mec gene.
MecA encodes for PBP2A- PBP no longer binds the oxacillin

49

MRSA - what are your options? (4)

Vancomycin
Linezolid
Daptomycin
Ceftaroline (only if MIC low)

50

VISA- what are your options?

Linezolid
Daptomycin
Ceftaroline

51

VRE- what are your options?

Linezolid
Daptomycin
Tigecycline
If UTI- nitrofurantoin
If penicillin susceptible- penicillin G

52

Pseudomonas- what are your options?

Tazocin
Gent/Tobra
Cefepime, Ceftazidime
Aztreonam
Ciprofloxacin
Meropenem NOT ertapenem
Colistin

53

Most common cause of PCR proven viral myocarditis?

Adenovirus!

54

Clinically, difference between meningitis and encephalitis?

In encephalitis there is clouded sensorium
In meningitis, they feel unwell but usually cognition is unchanged, unless they are postictal

55

When do the new guidelines say IE is indicated? (4)

1. PMH IE
2. Prosthetic heart valve
3. Heart Tx with an abnormally functioning valve
4. Unrepaired cyanotic CHD, Repaired in last 6 months, or persistent leak adjacent to synthetic material used for repair.

Additionally, taking antibiotics just to prevent endocarditis is not recommended for patients who have procedures involving the reproductive, urinary or gastrointestinal tracts.

56

Most common cause of OM?

S aureus
If sickle cell- salmonella

57

Tetanus caused by what bug and what is the treatment?

Clostridium tetani
Spores prevent GABA release

Treatment is IV metronidazole (better than penicillin)
IM human tetanus immunoglobulin for high risk wounds.

58

All the gram positive bacilli *there are 5*...?
ABCDL

Actinomyces
Bacillus anthracis (anthrax)
Clostridium
Diphtheria: Corynebacterium diphtheriae
Listeria monocytogenes

59

Penicillin allergy in cellulitis?

Clindamycin or clarithromycin