Revision gems Flashcards by alice Sawka

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.

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Hypervirulent c diff has what clinical implications?

increased complications, mortality, and relapse

associated with fluroquinolone resistance.

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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

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C diff outbreak control- what works?

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

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C diff looks like what type of bug…

gram positive spore forming rod

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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

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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

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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)

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Where does HIV rank as an independent risk factor?

Not as high as smoking

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Which HAART is the worst for cardiovascular risk?

Abacavir and the protease inhibitors

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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

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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

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Pneumonia in an alcoholic… think?

Klebsiella

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Lymphogranuloma venerum is secondary to what?

Chlamydia trachomatis

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Stages of lymphogranuloma venerum ?
(3)

And how do you treat?

small PAINLESS pustule which later forms an ulcer
Painful bilateral inguinal lymphadenopathy
Proctocolitis

Tx is doxycycline

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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)

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Causes of a painless genital ulcer?

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

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What are the alpha haemolytic streps?

alpha = PARTIAL haemolysis
Looks green on the plate

S viridans
S pneumoniae

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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

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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"

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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

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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)

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Who gets PEP for varicella?

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

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Legionella is found in what sources?

L longbechiae- potting mix

L pneumophilia- humidifiers, cooling towers

Legionella clinical picture

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

Legionella treatment

Macrolide | Cipro

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

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.

Melioidosis is caused by what?

Burkholderia pseudomallei Gram negative rod, soil saprophyte

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

How do you manage melioid?

Ceftazidime, carbapenem | GCSF in septicaemia

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

HHV8 is associated with what cancers?

Kaposi's sarcoma Primary effusion lymphoma Multicentric castlemans disease

HTLV-1 is associated with which pneumonia?

Adult T cell leukaemia

Opisthochis viverrini and Chonorchis sinensis are associated with what cancer?

CholangioCa

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

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)

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

Overwhelming post splenectomy infection- what is the empirical treatment?

Ceftriaxone and vancomycin

Empirical treatment for suspected IE?

Gent Benpen Fluclox

Does entamoeba cause eosinophilia?

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

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

Gram stain CSF: | Gram positive cocci

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

Gram stain CSF: | Gram neg cocci

N meningitidis Ceftriaxone

Gram stain CSF: | Gram positive bacilli

Listeria Penicillin G or ampicillin

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

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

What defines MRSA?

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

MRSA - what are your options? (4)

Vancomycin Linezolid Daptomycin Ceftaroline (only if MIC low)

VISA- what are your options?

Linezolid Daptomycin Ceftaroline

VRE- what are your options?

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

Pseudomonas- what are your options?

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

Most common cause of PCR proven viral myocarditis?

Adenovirus!

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

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.

Most common cause of OM?

S aureus | If sickle cell- salmonella

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.

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

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

Penicillin allergy in cellulitis?

Clindamycin or clarithromycin