Infectious Diseases Flashcards
Live vaccines
BCG
Japanese encephalitis
MMR
Rotavirus
Oral typhoid
Varicella
Yellow fever
Zoster
Treatment of choice for aspergillus?
Voriconazole
Treatment of choice for nocardia?
Sulfa-based medications
Bactrim - TMP-SMX
Treatment of choice for strongyloides?
Ivermectin
Side effects of linezolid?
BM depression (reversible, with prolonged use)
Neuropathy (irreversible)
Optic neuropathy (rare)
Serotonin syndrome (avoid concurrent tramadol/SSRIs)
Mechanism of resistance to vancomycin?
D-Ala D-Ala > D-Ala D-Lac
VanA vs. VanB vs. VanC gene clusters?
VanA - transferable, resistant to vancomycin & teicoplanin, high vancomycin MIC
VanB - transferable, moderate resistance to vancomycin but teicoplanin sensitive
VanC - non-transferable, resistant to vanc (low-level) but teicoplanin sensitive
VanA vs. VanB vs. VanC gene clusters?
VanA - transferable, resistant to vancomycin & teicoplanin, high vancomycin MIC
VanB - transferable, moderate resistance to vancomycin but teicoplanin sensitive
VanC - non-transferable, resistant to vanc (low-level) but teicoplanin sensitive
Indications for CT prior to LP
Immunocompromised state
History of CNS disease
New onset seizure
Papilloedema
Focal neurological deficit
Abnormal GCS
Common causes of bacterial meningitis in adults
SHIN
Strep. pneumoniae
Haemophilus influenzae
Neisseria
Causes of aseptic meningitis?
4 high-risk criteria requiring TOE if bacteraemic:
Community acquired bacteraemia
IV drug use
High risk cardiac condition
Indeterminate/positive TTE
In patients without above 4, normal TTE ruled out IE with sensitivity of 97% and NPV of 99%
Indications for surgery in infective endocarditis
(1) Heart failure
- Severe valve dysfunction
- Poor cardiac function
- Pulmonary oedema
(2) Uncontrolled infection
- Root abscess
- Persisting fevers/positive BC despite >10 days therapy
- Fungal/MDRO
(3) Prevention of embolism
- Vege >15mm
- Large vege + embolic episodes
If valve culture negative at surgery, antibiotics can be stopped 2/52 post op
Class of drug: raltegravir, dolutegravir?
Integrase inhibitors (HIV)
Class of drug: ritonavir, lopiravir, indinavir?
Protease inhibitors (HIV)
Class of drug: tenofovir, adefovir?
Nucleotide reverse transcriptase inhibitors (HIV)
Class of drug: abacavir, emtricitabine, lamivudine?
Nucleoside reverse transcriptase inhibitors (HIV)
What HIV medication is associated with hypersensitivity reactions ?
Abacavir
Test for HLAB5701 prior to commencing therapy
Examples of gram positive rods?
Non-spore forming:
Listeria monocytogenes
Corynebacterium
Gardnerella vaginalis
Spore forming:
Bacillus cereus
Clostridium
Treatment of uncomplicated malaria?
Symptomatic but without features of severe malaria.
Oral therapy can be used.
1st line: artemether + lumefantrine (can be used after 1st trimester)
If in 1st trimester: atovaquone + proguanil.
If P vivax/P ovale: need primaquine for hypnozoites.
Features of severe malaria?
- Blood parasite count >100 000/mL (>2% cells parasitised)
- Impaired consciousness
- Jaundice
- Oliguria/AKI
- Respiratory distress
- Severe anaemia
- Hypoglycaemia
- Vomiting
- Metabolic acidosis
Treatment of severe malaria?
Immediate IV treatment.
Usually caused by P falciparum.
1st line: IV artesunate
IV ceftriaxone 2g as concurrent bactereraemia common.
Paracetamol - reduces risk of haemolytic AKI
Which species of malaria have dormant stages?
P vivax
P ovale
Dormant = hyponozoite = liver
Definition of drug-resistant TB?
Resistance to one or more TB drugs
Definition of multidrug-resistant TB (MDR-TB)?
Resistance to at least isoniazid AND rifampin
And possibly other TB drugs.
Definition of extensively drug-resistant TB (XDR-TB)?
Resistance to isoniazide, rifampin, a fluoroquinolone and at least one second line injectable agent or linezolid.
Most important predictors of drug-resistant TB?
- Previous episode of TB treatment
- Persistent or progressive clinical and/or radiographic findings whilst on first-line TB therapy
- Residence/travel to a region with high prevalence of drug-resistant TB
- Exposure to an individual with known/suspected infectious drug-resistant TB
Treatment for drug susceptible pulmonary TB?
Traditional regimen of ≥6 months
- 2 months intensive phase
- ≥4 months continuation phase
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
After completion of intensive phase, repeat clinical assessment + repeat sputum AFB
- Routine CXR not required if improving clinically
Indications for shortened regimen for TB?
Non-pregnant patients with drug susceptible TB in absence of extra pulmonary involvement.
Exclusion criteria:
History of cardiac disease
Advanced liver/renal disease
Pregnant/lactating women
Rifapentin, moxifloxacin, isoniazid, pyrazinamide
- 8 weeks intensive phase
- 9 weeks continuation phase
Role of pyridoxine (vit B6) in TB?
Given to patients with isoniazid and at risk of neuropathy (pregnancy, HIV, diabetes, EtOH, renal failure)
Isoniazid prevents conversion of pyridoxine to active form. Needed as cofactor for GABA.
ESCHAPPM organisms?
- Enterobacter spp
- Serratia spp.
- Citrobacter freundii
- Hafnia spp.
- Aeromonas spp.
- Proteus spp. (except P mirabilis)
- Providencia spp.
- Morganella morganii
AmpC beta lactamase genes
Inducible
Clinically important CPE/CREs?
- Klebsiella pneumoniae carbapenemase - KPC
- New Delhi metallo-beta-lactamase proteinase - NDM
- Oxacillin-type beta lactamase 48 - OXA 48
- Verona integron encoded metallo-beta-lactamase - VIM
- Imipenem hydrolysing metallo beta lactamase - IMP
CSF in bacterial meningitis?
High opening pressure
Elevated WCC (primarily PMNs)
Low glucose
High protein
Neisseria, S pneumoniae, Listeria
CSF in viral meningitis?
Normal/high opening pressure
Elevated WCC (primarily lymphocytes)
Normal glucose (may be low in HSV)
Elevated protein
HSV, VZV
CSF in GBS?
Clear
Normal/high opening pressure
Normal WBC
Normal glucose
High protein ++
Albuinocytologic dissociation
NS5B nucleotide inhibitors?
Sofosbuvir
NS5A nucleotide inhibitors?
Velpatasvir
Elbasvir
Ledipasvir
Drug of choice for Hep B treatment during pregnancy?
Tenofovir
Indications for Hep B treatment in chronic HBV infection?
Immune clearance
- HBsAg positive
- HBeAg positive
- Anti-HBeAg negative
- ALT >19 women, >30 men
- Viral load >20,000
Immune escape
- HBsAg positive
- HBeAg negative
- Anti-HBeAg positive
- Elevated ALT
- Viral load >20,000
Detectable viral load + cirrhosis
When to start HCC surveillance in hep B?
Cirrhosis
ATSI >50
Asian male >40
Asian female >50
African >20
1st degree relative with HCC
Indications for Hep B treatment with chemotherapy/immunosuppression?
If HBsAg positive, should have antiviral therapy if undergoing chemotherapy/immunosuppression.
If B-cell depleting (e.g. rituximab), need to continue for 18-24 months post therapy. Also with B-cell depleting therapy, indication includes HBsAg negative/anti-HBc positive.