FRACP questions Flashcards
Recent cardiac surgery - presenting with fatigue, pain, fever, pain, heat/pus at surgical site, night swears. Suspect which bug?
Mycobacterium chimaera
IRIS
Immune system begings to recover but then responds to a previously acquired opportunistic infection with an overwhelming immune response that makes the symptoms worse.
Two main scenarios can occur:
1/ ‘unmasking’ of an occult opportunistic infection
2/ ‘paradoxical’ symptomatic relapse of a prior infection despiet microbiologic treament success.
Best treatment option is not known, but mosty common is to administer Abx or antiviral drug against pathogenic bug.
Common pathognes include: CMV, MAC, HZV, pneumocystis pneumonia andf TB.
If HIV pt has LOW CD4 and opportunistic infecruiin , generally advised to treate/control infection first before HAART is initiated.
Empirical Abx treatment for brain abscess from haematogenous spread?
Metronidazole and ceftriaxone
Ertapenems any pseudomonal cover?
NO
Carbapenems broadest spectrum of the beta-lactam Abx,aerobic and anaerobic gram negatibe bacilli also cover pseudomonas aeruginosa.HOWEVER among the three known carbapenems ERTAPENEM has NO activity against pseudomonal aeruginosa.
Carbapenems generally inactive against MRSA, VRE and enteroccocus faecium.
Fidaxomicin used in what?
narrow spectrum macrocylcic antibiotic drug with selective eradication of pathogenic Clostridum diffcilie in mild to moderate.(but not against gram negative bacteria)
HIV patient with active TB, when to start AART?
ALL HIV patient should go on AART
TB treatment started immediately. And the AART based on CD4 counts:
- IF CD 4 count <50, start 2 weeks after treatment
- IF CD4 count >50 with severe HIV disease/manifestations, start 2-4 weeks after treatment
- IF CD4 count >50 and nonsevere HIV disease, treatment should start within 8-12 weeks of treatment
What is Avibactam?
NEW CLASS DBOs (diazabicyclooctanes) is a non-b-lactam-b-lactamase inhibitor which has a broader spectrum of activity than other inhibitors.
Avi DOES NOT induce beta lactamase production (unlike clauvanic acid etc) but actually inactivates b-lactam and its inhibition is mostly reversible
Best screening test for syphillis?
T.pallidum Enzyme Immunoassay (EIA)
detects both IgM and IgG
HIV and TB, what is NOT recommended as part of treatment?
Rifapentin is NOT recommended for treatment of latent or active TB in HIV infected patients recieving ART
TB and Interferon Gamma Release Assay (IGRA)
- IGRA detects T-cell responses to MTB
- IGRA has very high specificty for TB when tested in low TB population with no risk factors
- IGRA is not recommended for diagnosing active TB
- Level of positivity of IGRA dos not predict active vs latent TB
- A negative IGRA DOES NOT exclude active TB as IGRA cannot differentiate between active and latent TB
When is a mantoux test considered postive?
- > 5mm in HIV infected person, immunosupressed, close contact of infectious TB and presence of old TB on CXR
- >10mm if medical risk factors, foreign born endemic TB area, healthcare worker, nursing home, prisoners
- >15mm for all other persons, BCG vaccinated
Name a drug not used in treatment of MDR TB
Clarithromycin
When is Bedaquilline used?
for MDR TB
- Oral diarylquinolone; targets ATP synthase
- 1st drug with novel mechanism approved by FDA for TB since 1971
When is Delamanid used?
In MDR TB
- Nitroimidazole class; inhibits mycolic acid synthesis
Sensitivity of Xpert MTB/RIF at picking up smear positive TB and identifying rifampicin resistance from a sputum sample?
98%
for smear negative sensitivity is 72.5%
Pneumococcal meningitis, Abx choice in pt with severe penicillin allergy?
Vancomycin + ciprofloxacin
Otehr option is moxifloxacin as single agent
Class of Caspofungin?
Echinocandins
inhibits enzyme 1-> 3 beta D glucan synthase and DISRUPT the integretiy of the fungal cell wall
Procedures requiring prophylactic Abx in patient with valvular disease?
Cephazolin
High risk GI procedures:
- dilatation of oesophageal stricture
- treatment of oesophageal varices
- ERCP with obstruction
- Endoscopic US with FNA
- PEG
High risk resp procedures:
- proc that involves incision or biopsy of the resp mucosa
- tonsillectomy
- adenoidectomy
- bronchoscopy WITH biopsy
Other high risk procedures:
- proc in patients with ongoing GI or GU tract infection
- proc on infected skin, skin structure or MSK tissue
- surgery to replace heart valves/intracardiac device
- ALL dental procedures that invovle manipulation of eitehr gingival tissue or the periapical region of teeth or perforation of the oral mucosa
NOT recommended in:
- colonoscopy
- gastroscopy
- C-section
Mechanism of gram negative resistance with linezolid
Efflux pump!
Male post TRUS biopsy given prophylactic norfloxacin, metro and gent - represents with sepsis. What treatment?
Meropenem!
suspected pathogen = ESBL bacteremia.
Which groups have the highest risk for developing invasive fungal infection?
AML
Allogenic HSCT
Heart, lung, liver transplant
Aspiration pneumonia treatment
Role of anaerobic organisms in aspiration pneumonia is frequently overestimated. In mild disease, penicillin effectively treats anaerobic organissm aspirated from the oropharnyx and the addition of metronidazole is not usually required.
The addition of metro is recommended in the following groups:
- putrid sputum
- severe peridontal disease
- hx of chornic hazardous alcohol consumptom
- development of lung abscess, empyema or necrotising pneumonia
- do not respond to empirical therapy
Daptomycin aint useful in what?
Pneumonia!
Is inhibited by surfactangt and therefore not useful in pneumonia!
Ambler classification of beta-lactamases
Class A = plasmid mediated and chromosomally-encoded: TEM and SHV enzymes
Class B = metalloenzymes: like New Delhi metallo-beta-lactamase (NDM-1)
Class C = chromosomally encoded cephalosporinases that may be inducible: AmpC enzymes
Class D = oxacillin hydrolising enzymes: OXA-1
Smallpox vs chicken pox rash
chicken pox = more truncal!
Meningitis treatment
