Infections in the Neurosurgical Intensive Care Unit

The value of cerebrospinal fluid lactate levels in diagnosing CSF infections in pediatric neurosurgical patients

PURPOSE

Diagnosis of cerebrospinal fluid (CSF) infections in patients following neurosurgical procedures can be challenging. CSF lactate (LCSF) has been shown to assist in differentiating bacterial from non-bacterial meningitis in non-neurosurgical patients. The use of lactate in diagnosing CSF-related infections following neurosurgical procedures has been described in adults. The goal of this study was to describe the role of LCSF levels in diagnosing CSF-related infections among neurosurgical children.

METHODS

We retrospectively collected data for all pediatric patients treated at a large tertiary pediatric neurosurgical department, for whom CSF samples were collected over a 2-year period. Lactate levels were correlated with other CSF parameters, surgical parameters, presence of CSF infection, and source of CSF sample (lumbar, ventricular, or pseudomeningocele).

RESULTS

A total of 215 CSF samples from 162 patients were analyzed. We found a correlation between lactate levels and other CSF parameters. Lactate levels displayed an inconsistent correlation with infection depending on sample origin. Irrespective of the CSF source, lactate levels could not sufficiently discriminate between those with or without infection. Lactate levels were correlated with recent surgery, and, in some of the subgroups, to the extent of blood in CSF.

CONCLUSIONS

LCSF levels are influenced by many factors, including the source of sample, recent surgery, and the presence of subarachnoid or ventricular blood secondary to surgery. The added value of LCSF for diagnosing CSF infections in children with a history of neurosurgical procedures is unclear and may be influenced by the extent of blood in the CSF.

Risk factors for meningitis after craniotomy in patients with subarachnoid hemorrhage due to anterior circulation aneurysms rupture

OBJECTIVES

Postoperative meningitis is a serious complication occurring after neurosurgical interventions. However, few investigations have focused specifically on the risk factors that predispose patients to meningitis after major craniotomy. This study identified the risk factors for postoperative meningitis after neurovascular surgery, and investigated the relationship between postoperative meningitis and clinical outcome.

PATIENTS AND METHODS

A total of 148 consecutive patients with subarachnoid hemorrhage (SAH) who underwent clipping surgery through a pterional approach within 72 h between January 2007 and September 2011 were retrospectively analyzed. The treatment strategy of our hospital for patients with SAH was based on the findings of digital subtraction angiography in the acute phase. Coil embolization was firstly considered, and clipping through craniotomy if indicated was performed as soon as possible. Prophylactic antibiotics were administered before beginning craniotomy and for at least 3 days after. Hydrocortisone was used to prevent hyponatremia if allowed by the medical condition of the patient. Intrathecal administration of nicardipine hydrochloride was given if required for vasospasm treatment. Meningitis was clinically diagnosed from the blood samplings and cerebrospinal fluid (CSF) examinations. Data were collected from the electronic and paper charts. The status of modified Rankin scale (mRS) 0-2 at discharge was defined as favorable outcome.

RESULTS

A total of 14 patients (9.5%) had meningitis during this study period. Symptomatic vasospasm was detected in 33 patients (22.3%), and 12 patients (8.1%) had permanent neurological deficits caused by vasospasm. Overall, 109 patients (73.6%) had favorable outcome. The longer duration of drainage placement, presence of CSF leakage, and intrathecal administration of vasodilatory agent showed significantly higher incidence of postoperative meningitis in univariate analysis (p=0.0093, 0.0017, and 0.0090, respectively). The proportion of favorable outcome patients at discharge (mRS 0-2) was significantly lower in patients with postoperative meningitis (35.7%) than in patients without it (77.6%) (p=0.0004). The duration of in-hospital stay was significantly longer in patients with postoperative meningitis (median 58.5, range 28-115 days) than in patients without it (median 38.5, range 19-149 days) (p<0.001). Multivariate logistic regression analysis showed that only presence of CSF leakage was associated with postoperative meningitis (p=0.0299).

CONCLUSION

Meningitis after surgery is still a serious complication that requires preventative intervention. The clinical outcome of patients with postoperative meningitis after neurovascular surgery is not still satisfactory.

Risk factors associated with postcraniotomy meningitis

OBJECTIVE

The authors conducted a retrospective cohort study to determine the incidence, bacteriological features, and risk factors for postcraniotomy meningitis.

METHODS

Patients older than 18 years who underwent nonstereotactic craniotomies between January 1996 and March 2000 and who survived for more than 7 days were included. Operations for placement of burr holes and shunts were excluded. Records of the first 30 postoperative days were abstracted. Host factors, types of craniotomy, and pre- and postoperative variables were evaluated as risk factors for meningitis

RESULTS

Among 453 patients, there were 25 cases of meningitis. Eight out of 12 culture-positive cases were the result of gram-positive cocci. Four hundred twenty (92%) patients received antibiotic prophylaxis, most commonly a first-generation cephalosporin. In multivariate analysis, the risk of meningitis was increased by surgery that entered a sinus (odds ratio [OR], 4.49; P = 0.018), an increase in the American Society of Anesthesiologists score (OR, 1.72; P = 0.023), and increases in the number of days of external ventricular drainage (OR, 1.21; P = 0.049) and intracranial pressure monitoring (OR, 1.24; P = 0.002).

CONCLUSION

Access of upper airway bacteria to the surgical wound, host factors as expressed by the American Society of Anesthesiologists score, and duration of device-related postoperative communication of the cerebrospinal fluid and the environment are major risk factors for postoperative meningitis after craniotomy.

CSF markers for diagnosis of bacterial meningitis in neurosurgical postoperative patients

OBJECTIVE: To evaluate the diagnostic usefulness of cerebral spinal fluid (CSF) cellularity, protein, neutrophils, glucose and lactate for detection of postoperative bacterial meningitis. METHOD: This prospective study was conducted in 28 postoperative neurosurgical patients from 2002 to 2005 at University of São Paulo. The CSF markers were plotted in a receiver operating characteristic (ROC) curve to evaluate their accuracy. RESULTS: Based on the area under ROC curve CSF glucose, cellularity, and lactate were considered good tests. Polymorphonuclear and protein did not achieve enough accuracy to be used clinically. CONCLUSION: The CSF glucose, lactate, and cellularity can be used for the diagnosis of bacterial meningitis. Moreover, it can be helpful to differentiate bacterial from aseptic meningitis.

The value of routine cultures of the cerebrospinal fluid in patients with external ventricular drains

OBJECTIVE

The purpose of this study was to determine whether routine cerebrospinal fluid (CSF) bacteriological cultures in patients with external ventricular drains (EVDs) can identify infections early and prevent complications related to bacterial ventriculitis.

METHODS

We retrospectively reviewed the microbiological reports and clinical data for all patients in whom an EVD was placed at a tertiary care pediatric neurosurgical center between 1984 and 1997. EVDs were inserted in the operating room or intensive care unit, and, in most patients whose EVD remained in place for more than 2 days, daily cultures of CSF were performed.

RESULTS

One hundred fifty-seven patients in whom 160 EVDs had been placed were included in the study. Forty-eight positive cultures were identified, of which the majority were determined to be contaminants. Seven infections were identified on the basis of microbiological criteria (i.e., a gram-positive stain and positive culture) and a subsequent positive culture. In all patients in whom infections developed, routine daily cultures of CSF were performed, and, in each instance, these cultures failed to identify the infections before clinical changes occurred. All seven patients with infection had fever (>38.5 degrees C) and peripheral leukocytosis (>11 x 10(3)/mm3) on the day the infection was identified, and one had a change in CSF appearance.

CONCLUSION

The results of this study suggest that routine culture of CSF in children with EVDs is not necessary, and that if CSF cultures are performed for new fever (>38.5 degrees C) or peripheral leukocytosis, neurological deterioration, or a change in CSF appearance, infections will be identified in a timely fashion. In situations in which these clinical indicators might be masked, routine cultures may be valuable.

Dysregulation of immune response following neurosurgical operations

BACKGROUND

Postoperative infections are common and potentially fatal complications in neurosurgical intensive care medicine. An impairment of immune function has been described after central nervous system surgery and in patients harboring malignant brain tumors. The aim of our study was to investigate whether differences in cell-mediated immunity can be found in patients undergoing craniotomy for surgery of glioblastoma or clipping of an intracerebral aneurysm.

METHODS

In order to determine the influence of the underlying disease on the immune system, we measured changes in cytokine concentrations (IL-6, IL-10, TGF-beta1) and lymphocyte-subsets (CD3+, CD3+HLA-DR+, CD4+, CD8+, CD19+, and CD16+56+) in 8 patients with glioblastoma and in 8 patients with an intracerebral aneurysm before, during and after the neurosurgical procedure.

RESULTS

In the comparison of glioblastoma and aneurysm patients, we could show that IL-6 plasma levels were pre- and intraoperatively higher in the aneurysm-group (P<0.05), and the plasma concentrations of IL-10 and TGF-beta were significantly elevated in the glioma-group. The lymphocyte-subsets showed a significantly lower percentage of NK-cells and activated T-cells in the glioma-group.

CONCLUSION

Our results document a significant dysregulation of immune response in glioma patients. This may be induced by elevated plasma concentrations of immunoinhibiting cytokines IL-10 and transforming growth factor-beta 1.

Cerebrospinal fluid tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, and interleukin-8 as diagnostic markers of cerebrospinal fluid infection in neurosurgical patients

OBJECTIVE

To evaluate whether cerebrospinal fluid concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, or IL-8 may be used as diagnostic markers for the differential diagnosis of aseptic vs. bacterial meningitis and/or ventriculitis in neurosurgical patients.

DESIGN

Prospective, observational study.

SETTING

University teaching hospital.

SUBJECTS

A total of 112 cerebrospinal fluid samples from 14 asymptomatic patients with normal cerebrospinal fluid after neurosurgery, 27 asymptomatic and 19 symptomatic patients with postneurosurgical aseptic meningitis, 32 patients with postneurosurgical cerebrospinal fluid infection, and 20 with severe subarachnoid and/or cerebral hemorrhage.

MEASUREMENTS AND MAIN RESULTS

Specific ELISA kits were used to analyze TNF-alpha, IL-1beta, IL-6, and IL-8 concentrations on cerebrospinal fluid samples. Elevations in cerebrospinal fluid concentrations of TNF-alpha, IL-1beta, IL-6, and IL-8 were induced by different diseases or neurosurgical procedures, but cerebrospinal fluid bacterial infection induced the highest concentrations. To discriminate between aseptic cerebrospinal fluid pleocytosis and cerebrospinal fluid infection with a specificity of 95%, cerebrospinal fluid leukocyte count >1700/mL, TNF-alpha >150 pg/mL, and IL-1beta >90 pg/mL showed sensitivities of 51%, 74%, and 90%, respectively. Sufficiently sensitive and specific cutoff points could not be found for cerebrospinal fluid IL-6 or IL-8.

CONCLUSION

Cerebrospinal fluid IL-1beta appears to be the best biochemical marker of cerebrospinal fluid infection in neurosurgical patients.

Vancomycin use in pediatric neurosurgery patients

OBJECTIVE

The objective of this article is to describe a pediatric neurosurgery patient population receiving vancomycin and examine the indications for and appropriateness of vancomycin use.

METHODS

A cross-sectional study was performed on the pediatric neurosurgery patients at Egleston Children's Hospital who received vancomycin from January 1 through December 31, 1996. Vancomycin use was compared with the Centers for Disease Control and Prevention Hospital Infection Control Practices Advisory Committee recommendations for vancomycin use.

RESULTS

Thirty patients received 115 doses of vancomycin. The median patient age was 8.0 years, and 17 (56.7%) were male. Vancomycin was used for prophylaxis in 28 (93.3%) patients and empiric therapy in 3 (10.0%) patients; one patient received vancomycin for surgical prophylaxis followed by empiric therapy for suspected meningitis. Vancomycin prophylaxis was initiated after the incision in 6 (21.4%) patients and was continued as prophylaxis for more than one dose in 26 (92.9%) patients.

CONCLUSIONS

Vancomycin was used primarily as surgical prophylaxis in pediatric neurosurgery patients, and use was not consistent with the Hospital Infection Control Practices Advisory Committee recommendations. These data suggest that for certain subpopulations, such as pediatric neurosurgery patients, there is a need for more specialized recommendations. Furthermore, prudent vancomycin use is warranted to successfully decrease the risk of further emergence of vancomycin resistance. Because vancomycin use may be prevalent in this population, assessment of vancomycin use in pediatric neurosurgery patients followed by establishment of vancomycin clinical guidelines may help improve the appropriateness of vancomycin use in this population.

Brain tumor surgery in geriatric patients: a critical analysis in 44 patients over 80 years

BACKGROUND

The decision of whether to operate on brain tumors in elderly patients has not been made easier despite diagnostic and therapeutic advances facilitating their diagnosis. Little is known about the outcome of brain tumor surgery in patients 80 years or older probably because the number of these patients, although increasing, is still small.

METHODS

The results of brain tumor surgery in 44 patients aged 80-86 years (mean age 83 years) were analyzed to determine which factors are relevant in the evaluation of the operative risk. The following parameters were analyzed with regard to the outcome: tumor volume, location, histopathology, preoperative condition, and concomitant diseases.

RESULTS

At discharge 19 patients (43%) had improved while 14 (32%) remained unchanged. Nevertheless, the overall results were unsatisfactory in 10 patients (23%), of whom 5 died in hospital. Tumor location, volume, and histopathology did not correlate with the outcome. The preoperative cerebrovascular condition and the existence of multiple concomitant diseases were clearly the determining factors for the outcome.

CONCLUSIONS

These results indicate that patients with life-threatening tumors or those causing persistent and intolerable brain dysfunction suffering from symptomatic cerebrovascular atherosclerosis as well as from multiple treatment requiring concomitant diseases did definitely not benefit from surgery.