Revision gems Flashcards
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.
Hypervirulent c diff has what clinical implications?
increased complications, mortality, and relapse
associated with fluroquinolone resistance.
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
C diff outbreak control- what works?
Infection control does not work
Antibiotic control does work- restrick FQ, cephalosporins
early and rapid diagnosis
C diff looks like what type of bug…
gram positive spore forming rod
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
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
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)
Where does HIV rank as an independent risk factor?
Not as high as smoking
Which HAART is the worst for cardiovascular risk?
Abacavir and the protease inhibitors
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
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
Pneumonia in an alcoholic… think?
Klebsiella
Lymphogranuloma venerum is secondary to what?
Chlamydia trachomatis
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
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)
Causes of a painless genital ulcer?
Syphilis
Lymphogranuloma venerum
Carcinoma
Granuloma inguinale (secondary to klebsiella granulomatis)
What are the alpha haemolytic streps?
alpha = PARTIAL haemolysis
Looks green on the plate
S viridans
S pneumoniae
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
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"
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
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)
Who gets PEP for varicella?
Immunocompromised - VZIG if less than 96 hours, also give aciclovir but limited evidence
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?
No
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)
- PMH IE
- Prosthetic heart valve
- Heart Tx with an abnormally functioning valve
- 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
