Guidelines for CSF Findings in Patients with Ventriculitis and Meningitis for VP Shunt Placement
The most effective approach for patients with ventriculitis and meningitis requiring VP shunt placement is to first remove all components of any infected shunt, establish external ventricular drainage, administer appropriate antimicrobial therapy, and only place a new VP shunt after achieving CSF sterility. 1
CSF Parameters to Monitor Before VP Shunt Placement
- CSF should be evaluated for cell counts with differential, glucose and protein concentrations, Gram stain, and bacterial cultures 2, 1
- Patients with bacterial meningitis typically have CSF glucose ≤35 mg/dL, CSF-blood glucose ratio of 0.23, CSF protein ≥220 mg/dL, ≥2,000 total white blood cells/μL, or ≥1,180 neutrophils/μL 2
- A minimum of 1-2 mL of CSF is required for cell count with differential, though 5 mL is optimal for comprehensive diagnostic testing 1
- CSF samples should be processed within 30-60 minutes of collection for optimal results 1
Treatment Algorithm Before VP Shunt Placement
Step 1: Remove Infected Hardware
- Complete removal of all components of an infected shunt is essential, as success rates are significantly lower when attempting to treat infection with the shunt in place 1, 3
- Place an external ventricular drain (EVD) to manage hydrocephalus while treating the infection 1
Step 2: Antimicrobial Therapy
- Begin empiric antibiotics based on Gram stain results and local resistance patterns 1
- For gram-negative bacilli infections, treatment duration should be 21 days 1
- For Streptococcus pneumoniae, treatment duration should be 10-14 days 1
- For staphylococcal infections, appropriate coverage is essential 1
Step 3: Monitor CSF Parameters
- Follow CSF cultures and inflammatory parameters to assess response to therapy 1
- Continue antibiotics until CSF is sterile and inflammatory parameters normalize 1, 3
Step 4: VP Shunt Placement Criteria
- Reimplant new shunt only after CSF sterility is achieved 1, 3
- Consider preoperative antibiotics for the new shunt placement to prevent reinfection 1
Special Considerations
Intraventricular/Intrathecal Antibiotics
- Intraventricular antibiotics may be considered for resistant organisms or when complete shunt removal is not possible 1, 4
- Recommended dosages for intraventricular administration include Vancomycin: 5-20 mg daily, Gentamicin: 1-8 mg daily, and Amikacin: 5-50 mg daily 1
- Intraventricular/lumbar intrathecal antibiotics can lead to rapid CSF sterilization (mean time 2.9 days) with 50% of patients achieving sterile CSF within 24 hours 4
EVD Management
- Implementation of strict EVD handling protocols can significantly reduce secondary infection rates 5
- The incidence of infection can be reduced from 33/1000 drain-days to 9/1000 drain-days with proper protocols 5
Hydrocephalus Management
- For patients with increased intracranial pressure (ICP), medical therapy and repeated lumbar punctures are recommended as initial management 2
- Most patients who develop increased ICP will require placement of a permanent shunt 2
- Early MRI of the brain and neurosurgical consultation are recommended for patients with hydrocephalus 2
Common Pitfalls and Caveats
- Ventricular fluid pressure may be normal in some cases of meningitis; this finding alone should not be used to exclude the diagnosis 2
- In patients with ventriculostomies who develop stupor or signs of meningitis, the catheter should be removed and the tip cultured 2
- In febrile patients with an intracranial device, CSF should be obtained for analysis from the CSF reservoir 2
- If CSF flow to the subarachnoid space is obstructed, it may be necessary to obtain CSF from both the ventricular system and the lumbar space, as one space may be infected while the other is sterile 2
- The timing of shunt reimplantation depends on the isolated microorganism and the extent of infection 1