What is the diagnosis and treatment for ventriculitis (inflammation of the ventricles)?

From the Guidelines

Ventriculitis should be treated with a combination of parenteral and intrathecal (IT) or intraventricular (IVT) administration of colistin, with a recommended dose of 125,000 IU once daily, as this approach has shown a successful clinical and bacteriological outcome of 89% in patients treated for A. baumannii CNS infections. The management of ventriculitis, particularly when caused by multidrug-resistant organisms like A. baumannii, is challenging due to the limited penetration of antibiotics into the cerebrospinal fluid (CSF) 1.

Key Considerations in Treatment

• The optimal duration of treatment for A. baumannii meningitis/ventriculitis is unknown, but it is suggested to continue antimicrobial therapy for 3 weeks, with monitoring of CSF sterilization to aid in tailoring the duration of therapy 1.
• Meropenem has been a drug of choice for nosocomial meningitis and ventriculitis to cover Gram-negative bacilli, including A. baumannii, but colistin is frequently the only available option for resistant strains 1.
• Sulbactam may constitute a valid alternative for carbapenem-resistant A. baumannii meningitis in isolates with low sulbactam MIC of ≤4 mg/L, considering its variable CNS penetration 1.

Treatment Approach

• The use of aminoglycosides IT or IVT, such as amikacin or tobramycin, can be considered as an alternative to colistin if the strain is susceptible, with daily doses ranging from 10–50 mg of amikacin or 5–20 mg of tobramycin 1.
• The need for a loading dose of 500,000 IU of colistin has been recently advocated, highlighting the importance of achieving therapeutic concentrations in the CNS 1.
• Three negative CNS cultures on separate days are required to decide on the end of IT/IVT treatment, ensuring that the infection is fully cleared 1.

From the Research

Definition and Treatment of Ventriculitis

• Ventriculitis is a severe infection that complicates central nervous system operations or is related to the use of neurosurgical devices or drainage catheters 2.
• The treatment of ventriculitis often involves the use of broad-spectrum antibiotics, such as vancomycin and meropenem, but their penetration into the cerebrospinal fluid (CSF) can be highly variable and may result in subtherapeutic concentrations 3, 4.

Antibiotic Penetration into CSF

• Vancomycin has been shown to have poor penetration into CSF, with a median CSF/serum ratio of 3% and high intersubject pharmacokinetic variability 3.
• Fosfomycin, on the other hand, has been found to have high penetration into CSF, with a median CSF penetration ratio of 46% and 98% of CSF levels above the susceptibility breakpoint of 32 mg/L 4.
• Other antibiotics, such as cefepime and gentamicin, have also been used to treat ventriculitis, with some success 5.

Treatment Strategies

• Therapeutic drug monitoring in both serum and CSF, as well as higher daily doses, may be necessary to ensure adequate trough levels and optimize patient therapy 3, 4.
• Novel dosing strategies, such as continuous infusion, may also be effective in reducing renal toxicity and improving antibiotic penetration into CSF 4.
• In some cases, direct antibiotic instillation into the CSF, in addition to intravenous antibiotic delivery, may be necessary to resolve the infection 2.

Challenges and Complications

• Ventriculitis can be difficult to distinguish from aseptic meningitis, inflammation that follows hemorrhagic strokes and neurosurgical operations 2.
• The associated microorganisms can be either skin flora or nosocomial pathogens, most commonly Gram-negative bacteria, which can demonstrate significant resistant patterns 2.
• Intraventricular antibiotic therapy may result in aseptic meningitis and seizures, particularly with the administration of aminoglycosides, polymyxins, and vancomycin 2.