Episode 178: Healthcare-Associated Ventriculitis and Meningitis Guidelines

In this episode, I’ll discuss the IDSA Healthcare-Associated Ventriculitis and Meningitis Guidelines.

These guidelines were published in February 2017

Empiric therapy

For empiric therapy in healthcare-associated ventriculitis and meningitis, select an agent that has CNS penetration and bacteriocidal activity against MRSA and pseudomonas. This will ensure coverage against the most likely pathogens which are:

Coagulase-negative staphylococci
Staph aureus
Propionibacterium
Escherichia coli
Enterobacter
Citrobacter
Serratia
Pseudomonas aeruginosa

A vancomycin based regimen that also includes cefepime, ceftazidime, or meropenem is sufficient.

Aim for a vancomycin trough of 15-20 mcg/mL (I aim for the high side of this range in CNS infections).

When using cefepime, ceftazidime, or meropenem for a CNS infection, I maximize CNS penetration by using a high dose extended infusion protocol (such as meropenem 2g over 3 hours every 8 hours).

Be aware that antibiotic treatment is more challenging if there is CNS hardware present during the infection that has not been removed. This is because biofilms tend to form on the prosthetic device, which inhibits the penetration of antibiotics. Rifampin should be added for patients with a CNS device present.

If the patient has anaphylaxis to beta-lactam antibiotics, replace the beta-lactam with aztreonam or ciprofloxacin.

If the patient is colonized or infected elsewhere with a highly resistant pathogen, the empiric regimen should also cover this pathogen.

Pathogen-specific therapy

The guidelines provide several recommendations on what antibiotics to use once the pathogen is identified.

For MSSA, use nafcillin or oxacillin. If the patient has a severe beta-lactam allergy, desensitize them or use vancomycin. Vancomycin is a weak antibiotic so I would strongly consider desensitizing the patient in this case.

For MRSA, use vancomycin but keep an eye on the MIC. As the MIC passes 1mcg/mL, the chance of success with vancomycin diminishes. Linezolid can be used instead and has excellent CNS penetration. However it is bacteriostatic. Daptomycin and sulfamethoxazole-trimethoprim may also be used.

Consider adding rifampin for any staph infection that is sensitive to it.

For propionibacterium, use penicillin G.

For gram-negative infections sensitive to ceftriaxone, step down to ceftriaxone.

For Pseudomonas, use either cefepime, ceftazidime, or meropenem based on sensitivity data. Aztreonam or ciprofloxacin may be used instead if the isolate is sensitive and the patient has a severe beta-lactam allergy.

For ESBL, use meropenem.

For Acinetobacter, use meropenem. If there is carbapenem resistance you are stuck with colistimethate sodium or polymyxin B given by the intravenous and intraventricular routes.

For candida, use liposomal amphotericin B plus 5-flucytosine. After clinical improvement patients with susceptible isolates can be switched to fluconazole. Echinocandins such as micafungin do not have adequate CNS penetration.

For Aspergillus, use voriconazole.

Intraventricular antibiotics

If the patient has not responded to systemic antibiotics, intraventricular antibiotics should be used. Controlled trials have not been done to evaluate the safety and efficacy of intraventricular antibiotics, so that is why they are reserved for the patient who has not responded to systemic antibiotics.

The initial dose of intraventricular vancomycin is based on the estimated ventricular volume. Give 5 mg in patients with slit ventricles, 10 mg in patients with normal-sized ventricles, and 15–20 mg in patients with enlarged ventricles.

The initial dose of other antibiotics such as aminoglycosides can be tailored similarly. Don’t give beta-lactam antibiotics via the intraventricular route due to the risk of seizure.

The frequency of intraventricular antibiotics is determined by the rate of CSF drainage: Once-daily dosing if CSF drainage is >100 mL/day, every other day if drainage is 50–100 mL/day, and every third day if drainage is <50 mL/day.

If you are measuring CSF antibiotic levels, aim for a trough to MIC ratio of 10-20.

Duration

In most cases, the duration of treatment should be 10-14 days. The guidelines do allow for the option of treating gram-negative infections for 21 days. If cultures are repeatedly positive, then the 10-14 day duration should begin after the last positive culture.

Antibiotic prophylaxis

Peri-procedural antibiotics may be used to prevent infection during CNS shunt and drain insertion. Post procedure, the antibiotics may be continued for up to 24 hours.

Regarding prolonged antibiotic prophylaxis the guidelines state:

76. Prolonged antimicrobial prophylaxis for the duration of the external ventricular drain is of uncertain benefit and not recommended (strong, moderate).

Shout out to Pharmacy Gavin for suggesting this topic!

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Starting Thursday, April 6, 2017, members of my Critical Care Pharmacy Academy will have access to my new Masterclass: Interpreting laboratory data in the ICU.  To learn more about the Academy and sign up go to pharmacyjoe.com/academy.

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If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.

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