Pediatric status epilepticus: How common is cerebrospinal fluid pleocytosis in the absence of infection?

PurposeTo determine the rate of cerebrospinal fluid (CSF) pleocytosis among children presenting with status epilepticus (SE) without proven central nervous system infection.MethodWe performed a retrospective cross-sectional study of all patients aged one month to 21 years of age who were evaluated in a single pediatric emergency department (ED) for SE between 1995 and 2012. We limited our study to those children who had a CSF culture obtained and excluded those children with proven viral or bacterial infection. We defined SE in a patient who had a single seizure or a cluster of seizures without regaining consciousness which lasted 30 min or longer. We defined CSF pleocytosis as a CSF white blood cells (WBC) > 10 cells/mm³ and a peripheral leukocytosis as WBC ≥ 15,000 cells/mm³. We compared the rate of CSF pleocytosis between children with and without peripheral leukocytosis using the Fisher's exact test.ResultsWe identified 289 ED visits for SE, of which 178 (62%) met study inclusion criteria. Seven children (4%, 95% confidence interval 1.7–8.2%) had CSF pleocytosis. More children with peripheral leukocytosis had CSF pleocytosis: (8.6% with peripheral leukocytosis vs. 0.9% without leukocytosis, p = 0.01).ConclusionCSF pleocytosis is relatively uncommon among children with prolonged seizures, even in the presence of peripheral leukocytosis. Therefore, all children with CSF pleocytosis after status epilepticus need comprehensive evaluation for central nervous system infection.     

Interpretation of lumbar cerebrospinal fluid leukocytosis after cranial surgery: The relevance of aseptic meningitis

Raised white cell count (WCC) in lumbar CSF is a commonly used marker of meningitis. The effect of cranial neurosurgery per se on lumbar WCC is not established. At this single centre, many patients undergo ICPM followed by lumboperitoneal shunt (LPS), with lumbar CSF WCC samples taken during insertion. We aimed to determine the effect of ICP bolt insertion on lumbar CSF WCC. We undertook a retrospective analysis of lumbar CSF samples in patients who had recently undergone 24-h ICPM. Thirty-three patients (16F:7M) aged 43.31 ± 12.1 years (mean ± SD) had lumbar CSF samples after ICPM. Fourteen had CSF sampled within 6 weeks and 19 after 6 weeks of ICPM. Twenty-five samples were taken during LPS insertion, 5 during lumbar drainage/puncture and 3 during LPS revision. All 33 patients were afebrile at the point of CSF sampling. The mean lumbar WCC within 6 weeks of ICPM was significantly higher than the mean lumbar WCC after 6 weeks, being 15.4 ± 18.0 and 2.32 ± 1.79 cells/microlitre respectively respectively. There was no significant increase in RBC. In patients with raised CSF WCC, 60% of raised WCC were predominantly lymphoctyes and 40% predominantly neutrophils. Only one patient grew an organism (S. aureus). We conclude that lumbar CSF WCC can be raised following minor intracranial surgery, despite no clinical sign of infection. We caution against using lumbar CSF WCC values independently as the only marker of infection following neurosurgery.     

Role of the urokinase plasminogen activator system in patients with bacterial meningitis

BACKGROUND: The urokinase plasminogen activator system has the potency to promote leukocyte recruitment and blood-CSF barrier breakdown, and thus may play an important pathophysiologic role in bacterial meningitis. METHODS: CSF and serum concentrations of urokinase-plasminogen activator (urokinase [uPA]), uPA receptor (uPAR), and PA inhibitor-1 (PAI-1) were quantified by ELISA in 12 patients with bacterial meningitis, control patients (n = 10) with noninflammatory neurologic diseases, and 10 patients with Guillain-Barré syndrome (GBS), a disease in which blood-CSF barrier disruption occurs without CSF pleocytosis. Casein zymography was used to determine PA-dependent plasminogen activation in the CSF. RESULTS: A marked increase in uPA-dependent plasminogen activation was detected in the CSF of patients with bacterial meningitis vs CSF of patients with GBS and controls. Accordingly, ELISA analysis of CSF revealed intrathecal upregulation of uPA protein in patients with bacterial meningitis. CSF concentrations of uPAR and PAI-1 were also elevated in these patients. The serum of patients with bacterial meningitis showed elevated protein levels of uPA, but not uPAR or PAI-1. Positive correlations were found between blood-CSF barrier breakdown and CSF uPA concentrations, and between CSF pleocytosis and CSF/serum ratios of the potent chemokine uPAR in patients with bacterial meningitis. Furthermore, an adverse clinical outcome in these patients correlated with serum uPA concentrations. CONCLUSION: In bacterial meningitis, the urokinase plasminogen activator system is involved in leukocyte recruitment and breaching of the blood-CSF barrier, and this may contribute to an unfavorable clinical outcome.     

Brain stem and cerebellar dysfunction after lumbar spinal fluid drainage: case report

Lumbar spinal fluid drainage is a common procedure to reduce the risks of cerebrospinal fluid (CSF) fistula after skull base fractures or various transdural neurosurgical procedures. Nevertheless, this simple and effective technique can lead to overdrainage and CSF hypovolaemia. This report describes the case of a young patient who had a lumbar drain inserted, to avoid CSF fistula after a pterional craniotomy with opening of the frontal sinus for the clipping of a ruptured aneurysm. The drain was removed after 48 hours because of underdrainage (<1 ml/h). Three days after drain removal, she developed rapid deterioration of her level of consciousness and signs of cranial nerves involvement, brain stem and cerebellar dysfunction. Intracranial pressure was low (<5 cm H(2)O) and MRI showed brain sagging and cerebellar foramen magnum herniation. The patient was successfully treated with epidural blood patch, ventricular drainage, and Trendelenburg position. The authors report this case because CSF hypovolaemia attributable to lumbar overdrainage is an insidious and threatening condition not easy to diagnose in the absence of detectable CSF leak. MRI and intracranial pressure monitoring confirm the diagnosis and permit better understanding of the physiopathology of brain sagging.     

Neuro-infections to be borne in mind]

We presented atypical manifestations in tuberculous meningitis (TbM) and herpes simplex encephalitis (HSE), lymphocytic dominant cerebrospinal fluid pleocytosis in bacterial meningitis, and a hitherto easily overlooked critical illness polyneuropathy (CIP) associated with sepsis. 1) We presented 2 TbM patients with atypical manifestations. One patient was a 25-year-old man who exhibited polymorphonuclear (PMN) dominant pleocytosis in CSF throughout his clinical course. He died the next day after a CSF culture yielded the growth of tuberculous bacilli, before receiving appropriate anti-TBM therapy. This was a rare TbM example of persistent PMN dominant CSF pleocytosis. The other patient was a 39-year-old woman whose CSF pleocytosis changed from lymphocytic dominant to PMN dominant about 1 month after the initiation of antituberculous chemotherapy. This CSF change was followed by multiple cerebral infarcts due to vauculitis caused by TbM. Administration of prednisolone caused marked improvement of the patient's symptomatology. Tuberculomas appeared transiently during anti-TbM therapy, consistent with paradoxical progression of tuberculoma. 2) A few patients with HSE may show atypical CSF findings such as PMN dominant pleocytosis, absence of pleocytosis, and low sugar value. Our national survey of HSE patients showed following percentages of these atypical findings: PMN dominant pleocytosis observed in 10% of the patients in the early stage and at the time of exacerbation, no pleocytosis in 0.9% (1 patient), and low sugar value in 4%. 3) Bacterial meningitis typically causes PMN dominant CSF pleocytosis. However, Listeria meningitis (LM) may cause lymphocytic dominant pleocytosis in 30% of the patients, particularly in elderly ones. We showed one such 69-year-old patient with persistent lymphocytic dominant CSF pleocytosis throughout the clinical course. 4) CIP, septic encephalopathy and critical illness myopathy are 3 major complications associated with sepsis. CIP is a frequent cause of neuromuscular weakness due to axonal dysfunction, which occurs to critically ill patients with sepsis, particularly when multiple organ dysfunctions are present. We showed our CIP patient associated with acute bacterial endocarditis and multiple organ failure. We should bear in mind these atypical manifestations, and frequent and important complications associated with sepsis such as CIP, to provide appropriate management to patients with neuro-infection and sepsis.     

Cerebrospinal fluid white cell count: discriminatory or otherwise for enteroviral meningitis in infants and young children?

Non-polio enteroviruses (EV) are the most common viruses causing aseptic meningitis in children. We aim to evaluate the cerebrospinal fluid (CSF) characteristics of neonates and children with EV meningitis with a view to determine whether it could be discriminatory or otherwise in making a positive diagnosis. We performed a 3-year (July 2008–July 2011) retrospective study of children ≤16 years, treated at a tertiary children’s hospital, with positive CSF EV polymerase chain reaction (PCR) and negative blood and CSF bacterial cultures. A total of 206 children were studied. The median CSF white cell count was 79 cells/mm³ (range 0–4608 cells/mm³). CSF pleocytosis was observed in 99/150 (66 %) aged ≤90 days, 3/4 (75 %) aged 90 days–1 year, and 49/52 (94 %) children ≥3 years. There was a huge variability in CSF pleocytosis in infants ≤90 days, where 34 % of them had no pleocytosis, while in 66 %, a wide range of pleocytosis that might even suggest bacterial meningitis was noted. CSF red cells were low, and protein or sugar values were not discriminatory. CSF pleocytosis in relation to increasing age was found to be statistically significant (p?<?0.001). Early lumbar puncture within 48 h of symptoms and absence of CSF pleocytosis was also statistically significant (p?=?0.039). CSF pleocytosis in EV meningitis is commoner in older children. As there was a huge variability in CSF pleocytosis in infants ≤90 days particularly, CSF analysis including EV PCR could avoid unnecessary antibiotic therapy.     

Matrix metalloproteinases contribute to the blood—brain barrier disruption during bacterial meningitis

In this study, we investigated the involvement of matrix metalloproteinases (MMPs) in the pathophysiology of bacterial meningitis. By using an enzyme immunoassay, high concentrations of MMP-9 were detected in the cerebrospinal fluid (CSF) of adult patients with bacterial meningitis but not in controls, and in patients with Guilain-Barré syndrome. Moreover, we observed significantly elevated concentrations of the tissue inhibitor of metalloproteinase-1 (TIMP-1) in the CSF of patients with bacterial meningitis, compared with controls. In a rat model of meningococcal meningitis, intracisternal injection of heat-killed meningococci caused a disruption of the blood–;brain barrier (BBB), and increase in intracranial pressure, and CSF pleocytosis paralleled by the occurrence of MMP-9 activity in the CSF 6 hours after meningococcal challenge. The MMP inhibitor batimastat (BB-94) significantly reduced the BBB disruption and the increase in intracranial pressure irrespective of the time of batmastat administration (15 minutes before and 3 hours after meningococcal challenge) but failed to significantly reduce CSF white blood cell counts. In conclusion, our results suggest that MMPs are involved in the alterations of BBB permeability during experimental meningococcal meningitis.     

Does lumbar cerebrospinal fluid reflect ventricular cerebrospinal fluid? A prospective study in patients with external ventricular drainage

Ventriculitis may sometimes occur after an external ventricular drain has been removed, and diagnosis has to be made by lumbar puncture. But are the lumbar findings comparable to previously obtained ventricular results? In a prospective study, sample pairs of ventricular and lumbar cerebrospinal fluid (CSF) were obtained at an interval of <30 min in 25 patients with increased intracranial pressure suffering from cerebral hemorrhage (n = 15), meningitis/encephalitis (n = 6), cerebral infarction (n = 3), and meningeosis carcinomatosa (n = 1). CSF was analyzed for protein, albumin, IgG, IgA, IgM, glucose, lactate, and leukocytes including cytological differentiation. A significant ventriculo-lumbar increase was observed for protein, albumin, and the immunoglobulins. Lactate was distributed equally in ventricular and lumbar CSF, as well as glucose in the cerebral hemorrhage subgroup (n = 15). Cell count failed to show a clear ventriculo-lumbar ratio. Cytological distribution was comparable in lumbar and ventricular CSF, except for macrophages showing a significant rostrocaudal decrease. In conclusion, in cases of clinically suspected bacterial central nervous system infection after removal of an external ventricular drain, lumbar CSF lactate, glucose, and cytology are comparable to previously determined ventricular values, and thus may help physicians to choose the best treatment.     

Mycoplasma meningitis resulting in increased production of cerebrospinal fluid: case report and review of the literature

PURPOSE: We report a case of increased cerebrospinal fluid (CSF) production in a child with concomitant mycoplasma meningitis. MATERIALS AND METHODS: This 4-year-old boy presented with a 2-week history of body aches, malaise, and headaches. He developed sudden onset of obtundation, apnea, left eye deviation, and bilateral dilated and unreactive pupils. A ventriculostomy was placed initially for a poor neurologic examination in the setting of likely meningitis. Initial intracranial pressure was high, and CSF production was supraphysiologic for the first few days of empiric, broad-spectrum treatment. Mycoplasma meningitis was diagnosed. The ventriculostomy was weaned after adequate treatment for mycoplasma meningitis. RESULTS AND CONCLUSIONS: At 4 months follow-up, the child remains shunt-free with only mild cognitive-linguistic impairment. Untreated mycoplasma meningitis may cause raised intracranial pressure (possibly as a result of increased CSF production) and result in a poor neurological examination. In this setting, CSF diversion in the form of an external ventricular drain may be beneficial to preserve neurologic function during treatment with antibiotics.     

Polyethylene glycol (PEG) hydrogel dural sealant and collagen dural graft matrix in transsphenoidal pituitary surgery for prevention of postoperative cerebrospinal fluid leaks

Cerebrospinal fluid (CSF) rhinorrhea is the most common complication after transsphenoidal pituitary surgery. The authors compare their previous experience using an autologous fat graft and lumbar drain placement in 107 patients with their current technique of using a dural sealant and collagen matrix in 97 patients to prevent postoperative CSF leak after pituitary tumor resection. The failure rate for CSF leak repairs between the two groups was similar. The use of a dural sealant and collagen matrix, however, has the advantages of decreased length of hospital stay, decreased length of Intensive Care Unit stay, avoidance of the morbidity of an extra abdominal incision, and avoidance of the risks of lumbar CSF drainage.     

Endoscopic third ventriculostomy in the treatment of hydrocephalus in posterior fossa tumors in children

OBJECT: The purpose of the present study is to assess the effectiveness of endoscopic third ventriculostomy (ETV) in children with hydrocephalus related to posterior fossa tumors. METHODS: Between September 1999 and December 2002, 63 children with posterior fossa tumors were treated at Santobono Hospital in Naples, Italy. Twenty-six patients had severe hydrocephalus. In order to relieve intracranial hypertension before tumor removal, 20 were treated with ETV, and 6 with ventriculo-peritoneal (VP) shunts. Twenty patients with mild hydrocephalus were treated with diuretics, corticosteroid agents, and early posterior fossa surgery, and 17 patients who did not have hydrocephalus were treated by elective posterior fossa surgery. Another 4 ETV were performed in the management of postoperative hydrocephalus. RESULTS: Preoperative ETV procedures were technically successful. One was complicated by intraventricular bleeding. The successful 19 preoperative ETV resolved intracranial hypertension before posterior fossa surgery in all cases. Three of these 19 patients developed postoperative hydrocephalus and were treated by VP shunt insertion after posterior fossa surgery. Out of the 4 ETV performed after posterior fossa surgery, only 2 were successful, both when the shunt malfunctioned. CONCLUSIONS: Endoscopic third ventriculostomy should be considered as an alternative procedure to ventriculo-peritoneal shunting and external ventricular draining for the emergency control of severe hydrocephalus caused by posterior fossa tumors, since it can quickly eliminate symptoms, and hence, can delay surgery scheduling if required. Even though ETV does not prevent postoperative hydrocephalus in all cases, it does protect against acute postoperative hydrocephalus due to cerebellar swelling. In addition, it eliminates the risks of cerebrospinal fluid (CSF) infection related to external drainage and minimizes the risk of overdrainage because it provides more physiological CSF drainage than the other procedures. Since postoperative hydrocephalus is very often physically obstructive, ETV should always be considered a possible treatment procedure.     

Gelatinase B [matrix metalloproteinase (MMP)-9] and collagenases (MMP-8/-13) are upregulated in cerebrospinal fluid during aseptic and bacterial meningitis in children

We investigated the protein expression of gelatinases [matrix metalloproteinase (MMP)-2 and -9] and collagenases (MMP-8 and -13) in cerebrospinal fluid (CSF) from patients with bacterial (BM, n = 17) and aseptic (AM, n = 14) meningitis. In both, MMP-8 and -9 were increased in 100% of patients, whereas MMP-13 was detectable in 53% and 82% respectively. Three patients with clinical signs of meningitis, without CSF pleocytosis, scored positive for all three MMPs. MMP-8 appeared in two isoforms, granulocyte-type [polymorphonuclear cell (PMN)] and fibroblast/macrophage (F/M) MMP-8. Analysis of kinetic changes from serial lumbar punctures showed that these MMPs are independently regulated, and correlate only partly with CSF cytosis or levels of the endogenous inhibitor, tissue inhibitor of matrix metalloproteinase-1. In vitro, T cells, peripheral blood mononuclear cells (PBMCs) and granulocytes (PMN) release MMP-8 and -9, whereas MMP-13 could be found only in the former two cell types. Using models of exogenous (n-formyl-Met-Leu-Phe, T cell receptor cross-linking) and host-derived stimuli (interleukin-2), the kinetics and the release of the MMP-8, -9 and -13 showed strong variation between these immune cells and suggest release from preformed stocks. In addition, MMP-9 is also synthesized de novo in PBMCs and T cells. In conclusion, invading immune cells contribute only partially to MMPs in CSF during meningitis, and parenchymal cells are an equally relevant source. In this context, in patients with clinical signs of meningitis, but without CSF pleocytosis, MMPs seem to be a highly sensitive marker for intrathecal inflammation. The present data support the concept that broad-spectrum enzyme inhibition targeting gelatinases and collagenases is a potential strategy for adjunctive therapy in infectious meningitis.     

Normal ventricular-CSF may comfound the diagnosis of tuberculous meningitis hydrocephalus

BACKGROUND: The standard procedure for the diagnosis of central nervous system (CNS) infections consists of cerebrospinal fluid (CSF) sampling, which is usually accomplished by a lumbar puncture. However, in some patients presenting with acute hydrocephalus submitted to immediate CSF drainage, the fluid is customarily obtained from the placed draining system. In addition, the CSF obtained from the ventricular and lumbar spaces in some cases may show unusual differences, both in physiological and pathological conditions. ILLUSTRATIVE CASES: We report two children who presented with confounding results in the initial studies of their ventricular and lumbar CSF who were subsequently diagnosed with tuberculous meningitis, causing delay in diagnosis and treatment. AIM. By reporting these cases, we wanted to alert the treating physician about the possibility of this discrepancy to avoid the delayed diagnosis and management of the affected patients. DISCUSSION: We comment on the possible pathophysiological mechanisms that may result in this dissociation in ventricular and lumbar CSF composition. CONCLUSIONS; Normal results in CSF studies, especially those of the ventricular fluid, do not always rule out the presence of tuberculous meningitis. We suggest obtaining a CSF sample from the lumbar subarachnoid space in doubtful, or suspicious, cases of CNS infection even in the presence of a normal ventricular CSF.     

Aseptic meningitis after transsphenoidal management of Rathke’s cleft cyst: case report and review of the literature

Aseptic meningitis after transsphenoidal surgery (TSS) for treatment of Rathke’s cleft cyst (RCC) is a rare complication caused by the leakage of the cyst contents within the subarachnoid space. We present a case of aseptic meningitis occurring after TSS for a RCC. During surgery, the cyst wall was subtotally removed, and intraoperative cerebrospinal fluid (CSF) leakage was observed. The patient developed meningeal signs and symptoms on the first postoperative day. CSF examinations were highly suggestive of aseptic meningitis. Histological examination confirmed a granulomatous inflammatory reaction of the RCC wall. Preexisting inflammation, subtotal cyst wall resection, intraoperative erosion of the diaphragma sellae and placement of a lumbar drain may be risk factors for the development of aseptic meningitis.     

Malplacement of Ventricular Catheters by Neurosurgeons: A Single Institution Experience

Introduction  The placement of cerebrospinal fluid (CSF) diversion devices requires an appropriate technical expertise associated with proper surgical training in order to minimize undue complications. This study sought to review a single institution’s experience with placement of external ventricular drains (EVD) and ventriculoperitoneal (VP) shunts as performed by neurosurgeons with procedure-specific training. Methods  A retrospective database review was conducted for all patients who underwent intraventricular CSF diversion over a 5-year period from March 2003 to February 2008. Included in the analysis were ventriculostomy procedures that included EVDs, VP shunts, and ventriculoatrial shunts. Results  A total of 138 patients underwent 212 ventriculostomy procedures. Seventy-one (51%) patients were male and sixty-seven (49%) were female. The median age was 50.1 years. A ventriculostomy-related hemorrhage was identified in 15 (7.1%) patients—4 of whom developed new symptoms. Twenty-six (12.3%) ventriculostomy catheters were malplaced as determined from post-procedural imaging. Ventriculostomy-related infections were identified in 7 (3.3%) patients, 4 of whom had EVDs and 3 of whom had VP shunts. Conclusion  The placement of intraventricular catheters by neurosurgeons remains a relatively safe and effective procedure that is associated with infrequent rates of symptomatic hemorrhage and infection.     

Substances which modulate leukocyte migration are present in CSF during meningitis.

We studied the effects on in vitro leukocyte migration of cerebrospinal fluid from 14 patients with and 7 patients without meningitis. Meningitic CSF, but not control CSF, contained activity that was chemotactic for peripheral blood leukocytes. In an unusual case of staphylococcal meningitis associated with a blunted CSF pleocytosis and a poor clinical response to antibiotics, an inhibitor of leukocyte chemotaxis was identified in the CSF. This inhibitor may have diminished local leukocyte accumulation in vivo and thereby adversely affected host defense mechanisms and clinical outcome. No inhibitors were found in other CSF samples tested. Soluble mediators present in CSF may modulate the local accumulation of leukocytes and therefore affect host defenses in meningitis.     

Third ventriculostomy through the lamina terminalis for intracranial pressure monitoring after aneurysm surgery: technical note

OBJECTIVE: A new ventriculostomy technique through the lamina terminalis is described. This technique is applied mainly during aneurysm surgery at the acute stage. METHOD: Thirteen patients were operated on intracranial aneurysms and, during the procedure, had the lamina terminalis fenestrated. A ventricular catheter was inserted into the third ventricule, left in place and connected to an external drainage system for further intracranial pressure (ICP) monitoring and/or cerebrospinal fluid (CSF) drainage. RESULTS: ICP readings and CSF drainage were obtained in all cases. No complication was recorded. CONCLUSION: Third ventriculostomy through the lamina terminalis is a simple and easy technique that can be used as an alternative to conventional ventriculostomy. This procedure can be indicated in cases where the ventricule is not reached by means of another technique, and when the decision to perform ventriculostomy is made at the end of aneurysm surgery.     

Infection rates in standard vs. hydrogel coated ventricular catheters

BACKGROUND: Infection related to external ventricular drain (EVD) use is a common neurosurgical complication. Modified catheters with a hydrophilic surface may impede bacterial adherence and thereby reduce catheter related cerebrospinal fluid (CSF) infection. METHODS: A prospective randomized clinical trial compared the occurrence of CSF infection related to use of either standard silastic or hydrogel coated EVD catheters (Bioglide, Medtronic). Enrolment was available to all adult neurosurgery patients undergoing placement of a first EVD, at three university centers. The catheters were presoaked in a low concentration of bacitracin solution for 5-10 minutes prior to insertion. Bacterial infection was defined by heavy growth in a single CSF sample or light/medium growth in two consecutive samples. A secondary analysis was also conducted for "probable" CSF infection, including patients started on antibiotics after light/medium growth in a single CSF sample. Statistical analyses included Kaplan-Meier survival curve estimates accompanied by Log Rank and Breslow tests. RESULTS: There were 158 randomized patients available to assess for EVD related infection of CSF. The two study groups had similar clinical characteristics including average duration of EVD use (8 +/- 4 days). Definite CSF infection occurred in seven and probable infection in another six (8% total). Infection incidence rose steadily from day 2 (1%) to day 11 (11%). There was no difference of daily occurrence of EVD infection between the two catheter types. CONCLUSIONS: Infection remains a common hazard in the use of EVD, and we found no reduction of infection using the hydrogel-coated catheters when presoaked in low concentration bacitracin solution.     

Comparison of ventricular and lumbar cerebrospinal fluid T cells in non-inflammatory neurological disorder (NIND) patients

The aim of the present study was to define the cellular composition of ventricular, as compared with lumbar, cerebrospinal fluid (CSF) in patients with non-inflammatory neurological disorders (NIND). We addressed this issue by determining the cellular composition of lumbar CSF from patients with normal pressure hydrocephalus (NPH) who were undergoing lumbar CSF drainage during evaluation for shunting procedures, and evaluating ventricular CSF from a subset of these who underwent subsequent placement of ventriculoperitoneal shunts. We determined the cellular composition of lumbar CSF from 18 patients with NPH, and found that the leukocyte differentials, and relative proportions of CD4+ and CD8+ central memory (TCM), effector memory (TEM) and naive cell (TNaive) populations, were equivalent to those found previously in studies of CSF from patients with NIND. We further evaluated cells in the ventricular CSF of five patients who had previously undergone lumbar drainage. Leukocyte differential counts, as well as CD4+ and CD8+ TCM, TEM, and TNaive proportions, were equivalent in matched ventricular and lumbar CSF samples. These observations support the hypothesis that leukocytes enter the CSF in a selective fashion, at its site of formation in the choroid plexus. The results implicate CSF T cells in the immune surveillance of the central nervous system.