ID - Guideline Updates Flashcards
Who should you suspect Listeria Meningitis in?
age >50 years, and in those with compromised cell-mediated immunity e.g. diabetes
Diagnosis of listeria meningitis
- LP essential to diagnosis and should be performed promptly
- CT head prior to LP is not necessary in all patients. Consider only if immunocompromised or features of raised ICP
- Blood and CSF culture prior to antimicrobials is helpful, but do not delay treatment if not able to be obtained expeditiously
Meningitis Risk Factors
- Abnormal communication between nasopharynx and subarachnoid space due to trauma or anatomic abnormality
- Anatomic or functional asplenia or immunoglobulin deficiency are risk factors for infection from encapsulated organisms (Pneumococci, Meningococci)
- Complement deficiency
- Terminal complement inhibitory - Eculizumab (2000 fold risk)
- HIV (not as much these days)
Kernig’s sign
Inability for fully flex knee when hip flexed to knee degrees
Brudzinski sign
spontaneous hip flexion during passive neck flexion
Indications for CT prior to LP: IDSA
Characteristic LP finding for HSV meningitis
CSF often contains many red cells – “bloody tap”
WCC predominance in Viral and TB meningitis
polymorphs may predominate early in the illness and later switch to lymphocytic predominant
Overall more lymphocyte predominant
pathogen most common for Mollaret’s meningitis?
HSV-2
LP findings for TB vs cryptococcal?
More WCC with TB, more protein
Empiric treatment for meningitis in adults
- Dexamethasone 10mg IV q6h (maximum 4 days)
- Ceftriaxone 2g IV BD
+/- Vancomycin 1.5g q12h (if pneumococcal risk)
+/- Benzylpenicillin 2.4g q4h (if listeria suspected)
(Ceftriaxone does NOT cover Listeria)
Typical TB meningitis presentation
Subacute presentation with fever, headache, drowsiness, meningism, and confusion over 2-3 weeks
- 50% have abnormal chest x-ray - an important clue!
- Predominant lymphocytic CSF >50%, with low CSF:blood glucose ratio (<0.5) and a high protein conc. >1.0 g/L
- Low numbers of bacilli in CSF - yield of ZN staining & culture adequate only if large volume of CSF is examined (>5 ml)
Typical Cryptococcus meningitis presentation
- Subacute presentation: headache, fever, altered mental state
- May not have classic meningism
- Advanced HIV (CD4 count <100) is main risk factor
- May be associated with cerebral mass lesion e.g. cryptococcoma
- Typically significantly elevated ICP – may need drainage or shunting to prevent vision/hearing loss
Cryptococcus species -> cryptococcus meningitis?
Cryptococcus neoformans (immunocompromised)
Cryptococcus gattii* (immuno-competent, on gum leaves etc)
Most common predisposing lesion for IE?
Mitral prolapse + regurg
(previous RHD MS)
Which Staph Aureus patients should you push for a TOE in?
Four high risk criteria requiring TOE identified:
- Community-acquired bacteremia
- IV drug use
- High risk cardiac condition
- Indeterminate or positive TTE
Or in a seperate study:
Main risk factors identified were:
- Patients with community-acquired SAB
- Prolonged bacteraemia >72 hours
- Cardiac prosthesis (i.e. ICD, PPM, or valve)
Streptococcus species most likely to cause IE?
Mutans
Gordonii
Sanguinis
S. Gallolyticus
Strep Gallolyticus
Previously known as Strep Bovis
Virulence factors:
- transmigration
- adherence to collagen-rich surfaces of cardiac valves
- biofilm formation
Endocarditis strongly associated with colon pathology
– 60% have concomitant adenoma / carcinoma on colonscopy
Significant of HACEK organisms
Oral Flora
If bacteraemic with highly suggestive of IE
What are HACEK organisms?
Gram negative bacilli that are slow to grow on culture media
Previously thought to cause lots of IE
HACEK organisms
- Haemophilus species
- Aggregatibacter actinomycetemcomitans
- Cardiobacterium
- Eikenella corrodens
- Kingella
Bacteria -> Culture negative IE?
- Bartonella
- Coxiella burnetii (Q fever)
- Brucella
- Legionella
- Tropheryma whipplei
Easier to grow these days.
Investigations in culture negative IE
Ideally three sets of blood cultures taken before antibiotics
Serological investigation helpful (but not available for Tropheryma whipplei)
If valve resected then request “16s ribosomal RNA sequencing” of valve tissue
Organisms in native vs prosthetic valve IE
native valve
* S. aureus
* Streptococci
* Enterococci
* HACEK
Prosthetic Valve
Early: <6 months post surgery
- Coag-neg Staphs
- S. aureus
- Enterococci
Late: >6 months post surgery Same as native valve (haematogenous spread)
Empiric ABx for native vs prosthetic valve IE?
Native valve:
* Benzylpenicillin 1.8g IV q4h (for strep)
* Flucloxacillin 2g IV q4h
* Gentamicin IV daily
Prosthetic Valve
* Flucloxacillin 2g IV q4h
* Vancomycin IV
* Gentamicin IV daily
For both options vans + gent seems to be a legit option also.
IE indications for surgery
IE Prophylaxis Guidelines 2008
High risk cardiac condition
PLUS
High risk procedure
High risk procedures for IE?
IE prophylaxis drug of choice?
Amoxicillin
CURB-65 components and score significance
SMART-COP Criteria
Treatment for CAP
Who to use steroids for pneumonia in
When should you use metronidazole for pneumonia?
aspiration pneumonia IF lung abscess or empyema is suspected
Not routine in aspiration pneumonia
(ATS/IDSA Pneumonia Guidelines 2019)
What percent exposed people become infected with TB, and what % of those -> active TB?
about 10% for each
What is the new terminology for TB?
latent TB -> TB infection
Active TB -> TB disease
What time frame do people with TB develop active TB/ TB disease?
50% with in 2 years, 50% many years later
CXR in TB/ HIV patient
Less typical - may be lower zone, diffuse infiltrate
cavitation uncoommon
less mediastinal adenopathy
TB drugs and HIV
rifampicin will lower levels of protease inhibitors (so use efavirenz instead)
TB testing in HIV patients?
should do a quant gold in all HIV +ve patients
May be falsely negative (esp if CD4 count < 100)
How long is TB therapy
- Initiation Phase: 2 months
- Continuation Phase: 4+ months
- Total course typically 6 months, but extended to 9 months if cavitary disease, pulmonary TB still positive at 2 months, bone or joint, TB meningitis (9 – 12 months)
When do you give steroids in TB?
TB meningitis of TB pericarditis
Drugs to use in MDR TB
Bedaquiline
Pretomanid
Linezolid
+/- Moxifloxacin
Indications for Latent TB treatment?
Therapeutic Guidelines (eTG) recommend treatment if:
- HIV infection
- Recent acquisition of disease / skin test converter
- Close contacts of patient with smear-positive pulmonary TB
- Immunosuppresssed e.g. TNF-alpha inhibitors, steroids
- Patients age <35 years even if no known TB contact*
- Healthcare workers
Risk for progression from latent to active disease
- Age < 5 years at time of exposure
- Body weight <90% of ideal weight
- Diabetes mellitus (30% lifetime risk)
- Gastrectomy or jejunoileal bypass
- History of untreated or inadequately treated active TB
- Immunosuppression
- Lung parenchyma abnormalities in smokers, silicosis* or cancer of head neck or lung
- Fibrotic changes on CXR consistent with past healed TB
- Recent contact with a person who has active TB
- Drug and alcohol use
- Social-economic disadvantaged peoples
- Very high risk especially when combined with HIV = S. African miners
DM and TB
3x risk of active TB
Increased severity/ mortality
Decreased treatment response
Treatment for latent TB?
Isoniazid
- 300g PO OD 6-9 months
