Summarizing an old article on the CSF Cell Index published in 2004, study has not been validated, but information is “nice to know.”
The CSF cell index is a ratio between the blood cells in the ventricles (in intracranial hemorrhage) and the peripheral blood. At the time of bleeding, blood in the ventricles is diluted within the CSF, and the relationship between WBC:RBC should equal that in the peripheral blood. This ratio, called the CSF cell index, should approximate 1 in the absence of infection.
The CSF cell index is calculated using to the following formula:
This study reported that the cell index rises 3 days before diagnosis of a catheter-related ventriculitis, and proper antimicrobial treatment led to a rapid decrease of the cell index. The study concluded that a significant increase in the cell index is highly indicative of nosocomial EVD-related ventriculitis in patients with IVH, and that the increase of the cell index usually precedes diagnosis by conventional means by 3 days.
Pfausler, B. et al. “Cell Index ? A New Parameter For The Early Diagnosis Of Ventriculostomy (External Ventricular Drainage)-Related Ventriculitis In Patients With Intraventricular Hemorrhage?”. Acta Neurochirurgica 146.5 (2004): 477-481.
Clinical signs of ventriculitis are difficult to recognize in SAH patients who are sedated, who have recently undergone neurosurgery, or have a sterile inflammatory response in the CSF due to the SAH. Clinical symptoms of SAH (headache, nuchal rigidity, AMS) closely resemble bacterial ventriculitis.
- new fever
- Fever occurs in 40 % after SAH +/- infection
- new nuchal rigidity
What to do?
Exclude other causes of infection
- physical examination
- blood / sputum / urinary cultures
Exclude other causes of AMS (HCP and ischemia)
- Neuroimaging with plain CT scan
- Clincally suspected bacterial ventriculitis – empirical antibiotic treatment for bacterial ventriculitis, but negative CSF cultures
- Confirmed Bacterial ventriculitis – (+) CSF culture for bacteria; if staph epidermidis – needs 2 consecutive positive cultures to rule out contamination
- No good discriminative tests, treatment initiated on first suspicion
- Antibiotic regimen for bacterial ventriculitis
- ceftriaxone 2 g BID + vancomycin 2 g BID
- ceftazidime 2 g TID + vancomycin 2 g BID if external CSF catheter in place
- culture negative – discontinue ABx (after 72h)
- culture positive – 2 weeks
- Physical Examination
- clinically suspected bacterial ventriculitis
- confirmed bacterial ventriculitis
- Blood work:
- CBC (WBC)
- BMP (glucose)
- Blood cultures x 2
- sputum cultures
- urinalysis with reflex to urine culture if (+)
- Plain CT scan
- CSF studies
- cell count
- Gram stain and culture
- CSF glucose
- CSF protein
- calculate cell index
- CSF lactate
- *CSF cytokine levels
- *CSF PCR for bacterial pathogens
- Treatment x 2 weeks
- ceftriaxone 2 g BID + vancomycin 2 g BID
- ceftazidime 2 g TID + vancomycin 2 g BID if (+) EVD
- discontinue within 72 hours if cultures are negative
Hoogmoed, J. et al. “Clinical And Laboratory Characteristics For The Diagnosis Of Bacterial Ventriculitis After Aneurysmal Subarachnoid Hemorrhage”. Neurocritical Care (2016): 1-9.
Ventriculitis carries a high mortality and morbidity, even with prompt diagnosis and treatment with antibiotics. A retrospective study from Kyoto Univeristy Graduate School of Medicine concluded that neuroendoscopic irrigation effectively treats ventriculitis, with lower mortality and duration of drainage catheter compared to historical control. The study population was small and the design was retrospective. Larger, prospective studies are needed to confirm these promising initial results.
Since 2011, this institution has adopted neuroendoscopic irrigation as standard treatment for ventriculitis. After diagnosis on MRI (high intensity on DWI and gad enhancement of ventricular lining), antibiotics was started and neuroendoscopic irrigation was performed, followed by drainage catheter insertion. Intraparenchymal abscess </=3cm in diameter was treated by placement of drainage catheter (without irrigation). Abscesses >3cm was surgically evacuated.
Method of Neuroendoscopic Irrigation:
An oval-shaped Burr hole was created in the left frontal bone for insertion of 2 drainage tubes. One tube was advanced into the abscess and the other was placed in the lateral ventricle under neuronavigator guidance. Pus was aspirated from the intraparenchymal abscess. A sheath was introduced to the lateral ventricle along with the ventricular drainage. Artificial CSF was flushed through the drainage tube. Ventricle was inspected with a rigid neuroendoscope, and white material suspended in the CSF was irrigated out. After sufficient irrigation, structures around foramen of Monro (initially covered by white material) were visualized. Under endoscopic guidance, the tip of drainage tube was placed at the posterior part of the lateral ventricle.
(a) Lateral ventricle filled with white, sticky material; (b) ventricular wall and choroid plexus (arrow) covered with grayish infectious material; (c) normal structures, choroid plexus (arrow), visualized after irrigation
Terada, Yukie et al. “Effectiveness Of Neuroendoscopic Ventricular Irrigation For Ventriculitis”.Clinical Neurology and Neurosurgery 146 (2016): 147-151.