Schreffler and colleagues performed a detailed decision analysis of the treatments options for CSF shunt infection based on available data since the introduction of these devices (135). The cure, failure, and death rates for three different strategies are summarized in the table below (68, 84, 170).
Results of Treatment Options in the Management of CSF Shunt Infections
|Shunt removal with immediate shunt replacement and IV antibiotics, with or without shunt antibiotics||64.4%||24.4%||11.1%|
|Shunt removal, EVD and IV antibiotics, with or without intraventricular antibiotics||87.7%||6.6%||5.7%|
Adapted from Schreffler RT et al.: Treatment of cerebrospinal fluid shunt infections: a decision analysis (135).
Systemic antibiotic therapy
Aside from CSF shunt hardware removal, the mainstay of infection control and treatment relies on antibiotic therapy. However, several pitfalls affect the decision to treat these clinical situations, as false positive cultures for skin contamination during a shunt tap can mislead treatment and partially treated infections can give negative cultures (e.g.., patients who had fever and headache and were treated for suspected upper respiratory tract infections but have evidence of a potential shunt malfunction).
- Initial antibiotic choice to cover common pathogens: The most common microorganisms isolated in cultures from infected shunts are Staphylococcus epidermidis (64%), followed by Staphylococcus aureus (29%) and gram-negative bacteria, mainly Escherichia coli and Klebsiella sp. (20%) (114, 134, 138). The choice of the antibiotic will vary with the organism isolated.
- Treatment tailored to organisms isolated: Antibiotic treatment should follow the local hospital’s epidemiologic patterns of infections, even if the microorganism has not been detected in the initial CSF stain, as cultures will dictate if there should be any therapeutic changes according to patterns of antibiotic resistance.
- Duration of treatment varies with organism: Duration of treatment is commonly 14 days but will vary with the infecting organism and the local experience in treating it.
- Resistant infections usually managed with change of EVD: In those patients with persistent growth of the same strain, antibiotic dosing is adjusted appropriately, and the clinician may prefer to exchange the EVD catheter as this occurrence indicates colonization. Another indication for exchange of the EVD catheter is evidence of nosocomial superinfection by other microorganisms. After EVD replacement, therapy is modified and continued for at least 10 days after the first negative culture is obtained.
Intraventricular antibiotic therapy
The intraventricular use of antibiotics has been reported in the past for the treatment of infections that have not responded well to systemic therapy or in addition to standard systemic IV therapy (66, 85, 124).
- Higher intraventricular concentration for antibiotic: The main purpose of intraventricular administration of antibiotics is to bypass the blood-brain barrier and achieve a bactericidal level in the CSF that is at least 10-fold greater than the minimum inhibitory concentration of the agent. In many cases only bacteriostatic levels are achieved when administering the drug intravenously, even after dose adjustment with optimization of peak and trough CSF antibiotic levels. Implicit in the decision to use this treatment is the consideration of whether or not there are any isolated CSF collections in the ventricles that the drugs will have difficulty reaching, since this occurrence will need to be dealt with to maximize the effectiveness of the intrathecal treatment.
- Suggested technique for daily intrathecal antibiotic: Strict sterile technique should be observed when using this technique to avoid contamination with nosocomial microorganisms. In the author’s institution, a daily dose of intraventricular antibiotic is delivered after a CSF sample has been withdrawn to investigate its characteristics and obtain cultures. The recommended antibiotic of choice is diluted in 5 ml of CSF and is delivered into the ventricle via the EVD catheter. The three-way valve is closed for 1 hour while the child is closely observed, providing that the CSF output and dynamics allow it. The EDV is then reopened to allow drainage into the burette. The author has experienced no major adverse events with the use of this treatment.
- Intraventricular purulent exudates commonly require washout: In general, when the author faces purulent ventriculitis with thick deposits in the ventricles, the patient is taken to the OR for EVD exchange. During this process, a ventricular lavage is performed to wash out as much debris as possible. Patients with intraventricular adhesions, retained hardware, or infected cysts pose formidable challenges, where endoscopic fenestration may play a role. However, sometimes the only option is direct surgical exploration.
- Extraoperative ventricular lavage has been reported: Ventricular lavage performed by introducing an antibiotic solution via an EVD catheter and then extracting the same volume either through the same route or through another catheter for continuous drainage can be used outside of the operative center. The author’s experience is that unless there is a one-to-one nurse-patient environment, this procedure is too labor intensive, as the input and output must match precisely to avoid accidents.