Isolated Intracranial Hypertension as a Presentation of Pediatric Lyme Borreliosis: A Case Report and Literature Review.

BACKGROUND: It is extremely rare for Lyme borreliosis to present solely with features of increased intracranial pressure. The treatment of pediatric Lyme neuroborreliosis with oral versus intravenous antibiotics remains controversial. METHODS: Case report and literature review. RESULTS: A 13-year-old male presented with five days of binocular diplopia, several weeks of headache, and a history of multiple tick bites six weeks prior. His examination showed a left eye abduction deficit and bilateral optic disc edema. Magnetic resonance imaging (MRI) of the brain with contrast showed tortuosity of the optic nerves, prominence of the optic nerve sheaths, and enhancement of the left fifth and bilateral sixth cranial nerves. Lumbar puncture showed an elevated opening pressure and a lymphocytic pleocytosis. Lyme IgM and IgG antibodies were positive in the serum and cerebrospinal fluid. The patient was treated with intravenous ceftriaxone for two days empirically followed by doxycycline by mouth for 19 days. Symptoms began improving after 48 hours. The strabismus resolved after two weeks, and the papilledema improved slowly with complete resolution at six months. CONCLUSIONS: Lyme neuroborreliosis can present as isolated intracranial hypertension in the pediatric population; it can be differentiated from idiopathic intracranial hypertension on MRI, and lumbar puncture and can be confirmed with serum antibody testing. Oral doxycycline can be considered for Lyme neuroborreliosis in children.

Effect of continuous hypertonic saline infusion on clinical outcomes in patients with traumatic brain injury.

Osmotic therapy has been recognized as an important treatment option for patients with traumatic brain injury (TBI). Nevertheless, the effect of hypertonic saline (HTS) remains unknown, as findings are primarily based on a large database. This study aimed to elucidate the effect of HTS on the clinical outcomes of patients with TBI admitted to the intensive care unit (ICU). We retrospectively identified patients with moderate-to-severe TBI from two public databases: Medical Information Mart for Intensive Care (MIMIC)-IV and eICU Collaborative Research Database (eICU-CRD). A marginal structural Cox model (MSCM) was used, with time-dependent variates designed to reflect exposure over time during ICU stay. Trajectory modeling based on the intracranial pressure evolution pattern allowed for the identification of subgroups. Overall, 130 (6.65%) of 1955 eligible patients underwent HTS. MSCM indicated that the HTS significantly associated with higher infection complications (e.g., urinary tract infection (HR 1.88, 95% CI 1.26-2.81, p = 0.002)) and increased ICU LOS (HR 2.02, 95% CI 1.71-2.40, p < 0.001). A protective effect of HTS on GCS was found in subgroups with medium and low intracranial pressure. Our study revealed no significant difference in mortality between patients who underwent HTS and those who did not. Increased occurrence rates of infection and electrolyte imbalance are inevitable outcomes of continuous HTS infusion. Although the study suggests slight beneficial effects, including better neurological outcomes, these results warrant further validation.

Systemic lupus erythematosus with chronic persistent intracranial hypertension: A case report.

OBJECTIVE: The aim is to investigate the clinical characteristics of systemic lupus erythematosus with intracranial hypertension. METHODS: The clinical characteristics of one case of systemic lupus erythematosus with chronic persistent intracranial hypertension were analyzed, and related literature was reviewed by searching Medline and Wanfang databases. RESULTS: Intracranial hypertension in SLE patients may occur at the onset or during the course of the disease. Our patient was diagnosed with IH 3 years after the onset of SLE. Headache and papilledema were the most common symptoms of intracranial hypertension, followed by nausea or vomiting, vision changes, and cerebral palsy. Our patient had a headache and cranial hypertension that lasted for years, but no papilledema was found. Corticosteroid is currently the mainstay of the treatment of IIH in patients with SLE, and immunosuppressive agents, acetazolamide, intravenous mannitol and furosemide are also used. However, our patient did not respond to these treatments and presents the characteristics of chronic persistent intracranial hypertension. CONCLUSION: Systemic lupus erythematosus with intracranial hypertension is a rare manifestation of SLE, which is not completely parallel to SLE activity. Headache and papilledema were the most common presenting symptoms. Different from previous reported cases, our patient had poor response to treatments, showing chronic and persistent characteristics.

Increased intracranial pressure in acute bacterial meningitis.

Acute bacterial meningitis (ABM) is associated with increased intracranial pressure (ICP) caused by bacterial invasion and the host response to infection. Antibiotic therapy is a sine qua non, and adjunct dexamethasone decreases mortality. The ICP increase may have a rapid course and death due to herniation is most often seen within the first week. Evidence regarding treatment of increased ICP in ABM is limited; this review summarises observational studies which point towards reduced mortality by applying a structured approach towards normalization of ICP in ABM.

Cryptococcal meningoencephalitis with Actinomyces odontolyticus sepsis: a case report and literature review.

BACKGROUND: The combined infection of actinomyces odontolyticus sepsis and cryptococcal encephalitis is rare in routine clinical practice. Thus, we presented this case report and literature review to provide clues to improve such patients' diagnoses and treatment processes. CASE PRESENTATION: The main clinical manifestations of the patient were high fever and intracranial hypertension. Then, we completed the routine cerebrospinal fluid examination, biochemical detection, cytological examination, bacterial culture, and India ink staining. Firstly, the blood culture suggested actinomyces odontolyticus infection, considering the possibility of actinomyces odontolyticus sepsis and intracranial actinomyces odontolyticus infection. Accordingly, the patient was administered penicillin for treatment. Although the fever was slightly relieved, the symptoms of intracranial hypertension did not relieve. After 7 days, the characteristics of brain magnetic resonance imaging and the results of pathogenic metagenomics sequencing and cryptococcal capsular polysaccharide antigen suggested that cryptococcal infection. Based on the above results, the patient was diagnosed with a combined infection of cryptococcal meningoencephalitis and actinomyces odontolyticus sepsis. Anti-infection therapy with 'penicillin, amphotericin, and fluconazole' was provided, improving the clinical manifestations and objective indexes. CONCLUSION: The combined infection of Actinomyces odontolyticus sepsis and cryptococcal encephalitis is first reported in this case report, and combined antibiotics with 'penicillin, amphotericin, and fluconazole' are effective.

Controlled Decompression Alleviates Motor Dysfunction by Regulating Microglial Polarization via the HIF-1α Signaling Pathway in Intracranial Hypertension.

Decompressive craniectomy (DC) is a major form of surgery that is used to reduce intracranial hypertension (IH), the most frequent cause of death and disability following severe traumatic brain injury (sTBI) and stroke. Our previous research showed that controlled decompression (CDC) was more effective than rapid decompression (RDC) with regard to reducing the incidence of complications and improving outcomes after sTBI; however, the specific mechanisms involved have yet to be elucidated. In the present study, we investigated the effects of CDC in regulating inflammation after IH and attempted to identify the mechanisms involved. Analysis showed that CDC was more effective than RDC in alleviating motor dysfunction and neuronal death in a rat model of traumatic intracranial hypertension (TIH) created by epidural balloon pressurization. Moreover, RDC induced M1 microglia polarization and the release of pro-inflammatory cytokines. However, CDC treatment resulted in microglia primarily polarizing into the M2 phenotype and induced the significant release of anti-inflammatory cytokines. Mechanistically, the establishment of the TIH model led to the increased expression of hypoxia-inducible factor-1α (HIF-1α); CDC ameliorated cerebral hypoxia and reduced the expression of HIF-1α. In addition, 2-methoxyestradiol (2-ME2), a specific inhibitor of HIF-1α, significantly attenuated RDC-induced inflammation and improved motor function by promoting M1 to M2 phenotype transformation in microglial and enhancing the release of anti-inflammatory cytokines. However, dimethyloxaloylglycine (DMOG), an agonist of HIF-1α, abrogated the protective effects of CDC treatment by suppressing M2 microglia polarization and the release of anti-inflammatory cytokines. Collectively, our results indicated that CDC effectively alleviated IH-induced inflammation, neuronal death, and motor dysfunction by regulating HIF-1α-mediated microglial phenotype polarization. Our findings provide a better understanding of the mechanisms that underlie the protective effects of CDC and promote clinical translational research for HIF-1α in IH.

Symptomatic intracranial hypertension in an adult patient with spinal muscular atrophy and arachnoid cysts receiving nusinersen.

 In patients with spinal muscular atrophy (SMA) headache after intrathecal administration of nusinersen is usually attributed to post-lumbar puncture syndrome. However, lumbar puncture opening pressure (LOP) has also been reported to be increased in children with SMA, both before and after treatment with nusinersen, although symptoms associated with increased LOP were not observed. We report to our knowledge the first case of symptomatic intracranial hypertension in an adult SMA patient. This 21-year-old man suffered from headache and vomiting followed by visual disturbances after the 12th injection of nusinersen. Bilateral papilledema was recognized ophthalmologically. MRI of the head showed signs of intracranial hypertension and additionally arachnoid cysts but not hydrocephalus. Symptoms resolved after 8 weeks of treatment with repeated lumbar punctures and acetazolamide. This case raises the possibility of intracranial hypertension as a complication of nusinersen therapy although arachnoid cysts represent another risk factor for intracranial hypertension. We recommend that patients suffering from headache after nusinersen injections should not only be questioned and examined for symptoms suggestive of post-lumbar puncture syndrome, but also intracranial hypertension.

Hypertonic Saline vs. Mannitol in Management of Elevated Intracranial Pressure in Children: A Meta-Analysis.

OBJECTIVE: To compare the efficacy and safety of two hyperosmolar agents (hypertonic saline vs. mannitol) used for the reduction of elevated intracranial pressure (ICP) in children. METHODS: A meta-analysis of randomized controlled trials (RCTs) was conducted and GRADE system (Grading of Recommendations, Assessment, Development and Evaluation) of evidence was applied. Relevant databases were searched till 31st May 2022. Primary outcome was mortality rate. RESULTS: Of 720 citations retrieved, 4 RCTs were included in the meta-analysis (n = 365, male = 61%). Traumatic and non-traumatic cases of elevated ICP were included. There was no significant difference in the mortality rate between the two groups [relative risk (RR), 1.09; (95% confidence interval (CI), 0.74 to 1.6)]. No significant difference was found for any of the secondary outcomes, except serum osmolality (being significantly higher in mannitol group). Adverse events like shock and dehydration were significantly higher in the mannitol group, and hypernatremia in the hypertonic saline group. The evidence generated for primary outcome was of "low certainty", and for secondary outcomes, it varied from "very-low to moderate certainty". CONCLUSIONS: There is no significant difference between hypertonic saline and mannitol used for the reduction of elevated ICP in children. The evidence generated for primary outcome (mortality rate) was of "low certainty", and for secondary outcomes, it varied from "very-low to moderate certainty". More data from high-quality RCTs are needed to guide any recommendation.

Safety of peripheral 3% hypertonic saline bolus administration for neurologic emergency.

BACKGROUND/OBJECTIVE: Hypertonic sodium chloride (HTS) is used for emergent treatment of acute cerebral edema and other neurologic emergencies. Central access is not commonly available in emergent situations and 3% HTS is utilized peripherally. Many studies have shown the safety of its administration at rates up to 75 mL/h, but there is a lack of data to establish the safety of peripherally administered, rapid bolus dosing in emergent situations. The objective of this study is to describe the safety of rapid, peripherally administered (≥ 250 mL/h) 3% HTS for neurologic emergencies. METHODS: This is a retrospective, cohort study including adult patients receiving 3% HTS via a peripheral IV site for elevated intracranial pressure, cerebral edema, or other neurological emergencies at a rate of at least 250 m/h between May 5, 2018 - September 30, 2021. Patients were excluded if they simultaneously received another hypertonic saline fluid. Baseline characteristics collected included HTS dose, rate and site of administration, indication for use and patient demographics. The primary safety outcome was incidence of extravasation and phlebitis within one hour of HTS administration. RESULTS: There were 206 patients receiving 3% HTS who were screened, and 37 patients met inclusion criteria. The most common reason for exclusion was administration at a rate < 250 m/h. The median age was 60 (IQR 45, 72) with 51.4% being male. The most common indications for HTS were traumatic brain injury (45.9%) and intracranial hemorrhage (37.8%). The most common administration location was the emergency department (78.4%). The median IV-gauge (n = 29) was 18 (IQR 18, 20), with the most common placement site being antecubital (48.6%). The median dose of HTS was 250 mL (IQR 250, 350), with a median administration rate of 760 mL/h (IQR 500, 999). There were no episodes of extravasation or phlebitis noted. CONCLUSIONS: Rapid, peripheral administration of 3% HTS boluses is a safe alternative for treatment of neurologic emergencies. Administration at rates up to 999 mL/h did not result in extravasation or phlebitis.

A Rare Report of the Coexistence of Sickle Cell Disease, Neurofibromatosis Type 1, and Intracranial Hypertension in a Pediatric Patient.

A pediatric female with sickle cell disease (SCD) and neurofibromatosis type 1 was noted to have incidental papilledema, with subsequent workup showing an elevated opening pressure. She was diagnosed with intracranial hypertension and began treatment with acetazolamide. Hydroxyurea was also discontinued. Acetazolamide was tapered off, and hydroxyurea was restarted with no worsening in her ophthalmologic exam. We report this case due to the rare occurrence of all 3 conditions, and while intracranial hypertension has been reported in SCD, the diagnostic workup for papilledema in hemoglobinopathies is not well defined. This case helps delineate the presentation and diagnostic workup of papilledema in SCD.

Acute Effects of Ketamine on Intracranial Pressure in Children With Severe Traumatic Brain Injury.

OBJECTIVES: The acute cerebral physiologic effects of ketamine in children have been incompletely described. We assessed the acute effects of ketamine on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in children with severe traumatic brain injury (TBI). DESIGN: In this retrospective observational study, patients received bolus doses of ketamine for sedation or as a treatment for ICP crisis (ICP > 20 mm Hg for > 5 min). Administration times were synchronized with ICP and CPP recordings at 1-minute intervals logged in an automated database within the electronic health record. ICP and CPP were each averaged in epochs following drug administration and compared with baseline values. Age-based CPP thresholds were subtracted from CPP recordings and compared with baseline values. Trends in ICP and CPP over time were assessed using generalized least squares regression. SETTING: A 30-bed tertiary care children's hospital PICU. PATIENTS: Children with severe TBI who underwent ICP monitoring. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We analyzed data from 33 patients, ages 1 month to 16 years, 22 of whom received bolus doses of ketamine, with 127 doses analyzed. Demographics, patient, and injury characteristics were similar between patients who did versus did not receive ketamine boluses. In analysis of the subset of ketamine doses used only for sedation, there was no significant difference in ICP or CPP from baseline. Eighteen ketamine doses were given during ICP crises in 11 patients. ICP decreased following these doses and threshold-subtracted CPP rose. CONCLUSIONS: In this retrospective, exploratory study, ICP did not increase following ketamine administration. In the setting of a guidelines-based protocol, ketamine was associated with a reduction in ICP during ICP crises. If these findings are reproduced in a larger study, ketamine may warrant consideration as a treatment for intracranial hypertension in children with severe TBI.

Pediatric myelin oligodendrocyte glycoprotein antibody associated disease-Asymmetric papilledema and elevated ICP are two of the chameleons: A case report.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody (MOGA) associated diseases are inflammatory immune-mediated demyelinating disorders with relapse potential involving the central nervous system. Multiple unusual clinical manifestations of those disorders were reported, making treatment decisions difficult. CASE PRESENTATION: A healthy 12-year-old obese boy presented with headache and bilateral asymmetric papilledema. The patient had a negative medical history. His neurological and general examinations were unremarkable, his initial magnetic resonance imaging showed elevated intracranial pressure (ICP) only. A lumbar puncture revealed increased opening pressure and pleocytosis. The MOGA titer was 1:320. He needed acetazolamide and steroid therapy. After 2 months of medication, weight loss, exercise, the patient symptoms significantly improved, papilledema resolved, and visual function improved. CONCLUSION: MOGA-associated disorders have a variety of clinical features, so a high index of suspicion is required for their diagnosis. Papilledema and an elevated ICP are 2 of the chameleons of MOGA-associated disorders. MOGA test may be useful in patients with elevated ICP and inflammatory cerebrospinal fluid profiles. An investigation of the possible association between those disorders and high ICP is warranted.

Effect of continuous infusion of hypertonic saline solution on survival of patients with brain injury: a systematic review and meta-analysis.

BACKGROUND: The objective was to determine the effects of continuous infusion of hypertonic saline solutions on outcomes of patients with brain injury. METHODS: Preferred Reported Items for Systemic Reviews and Meta-Analysis guidelines were followed. We searched the MEDLINE and COCHRANE clinical trials register (through December 2021) and reference lists of articles. We included all clinical trials conducted in brain-injured patients hospitalized in intensive care units evaluating continuous infusion of hypertonic saline solution (osmolarity above 308 mOsm/L). Two reviewers extracted data that were checked by two others. The primary outcome was the in-hospital mortality rate. The main secondary outcomes were the rates of intracranial hypertension, an unfavorable neurological outcome at day 90, and adverse events. RESULTS: We identified 23 clinical trials reporting the use of continuous infusion of hypertonic saline solution in brain-injured patients. The primary outcome was available in 10 studies (n = 1883 patients). The odds ratio (OR) for in-hospital death with the intervention was 0.68 (95% confidence interval (CI), 0.54-0.85, I2 = 0%). In the subgroup of studies including only traumatic brain-injured patients (7 studies, n = 1521 patients), the OR for the primary outcome was 0.74 (95%CI 0.57-0.95) with the intervention. The OR for intracranial hypertension and unfavorable neurological outcome at day 90 were 0.66 (95%CI 0.49-0.88, I2 = 42%, n = 787 patients) and 0.61 (95%CI 0.46-0.81, I2 = 15%, n = 956 patients), respectively. Regarding safety, the OR of acute kidney injury and severe hypernatremia were 0.82 (95%CI 0.47-1.44, I2 = 0%) and 3.38 (95%CI 2.16-5.27, I2 = 24%). CONCLUSIONS: Continuous hypertonic saline solution infusion reduced in-hospital mortality without increasing the risk of unfavorable neurological outcome at day 90 in brain-injured patients hospitalized in intensive care units. Given the inclusion of observational and heterogeneous studies, further randomized studies are needed before developing recommendations for implementation at the bedside. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021221367. Registered 13 May 2021.

Co-administration of Ketamine in Pediatric Patients with Neurologic Conditions at Risk for Intracranial Hypertension.

BACKGROUND: Ketamine has traditionally been avoided as an induction agent for tracheal intubation in patients with neurologic conditions at risk for intracranial hypertension due to conflicting data in the literature. The objective of this study was to evaluate and compare the effects of ketamine versus other medications as the primary induction agent on peri-intubation neurologic, hemodynamic and respiratory associated events in pediatric patients with neurologic conditions at risk for intracranial hypertension. METHODS: This retrospective observational study enrolled patients < 18 years of age at risk for intracranial hypertension who were admitted to a quaternary children's hospital between 2015 and 2020. Associated events included neurologic, hemodynamic and respiratory outcomes comparing primary induction agents of ketamine versus non-ketamine for tracheal intubation. RESULTS: Of 143 children, 70 received ketamine as the primary induction agent prior to tracheal intubation. Subsequently after tracheal intubation, all the patients received adjunct analgesic and sedative medications (fentanyl, midazolam, and/or propofol) at doses that were inadequate to induce general anesthesia but would keep them comfortable for further diagnostic workup. There were no significant differences between associated neurologic events in the ketamine versus non-ketamine groups (p = 0.42). This included obtaining an emergent computed tomography scan (p = 0.28), an emergent trip to the operating room within 5 h of tracheal intubation (p = 0.6), and the need for hypertonic saline administration within 15 min of induction drug administration for tracheal intubation (p = 0.51). There were two patients who had clinical and imaging evidence of herniation, which was not more adversely affected by ketamine compared with other medications (p = 0.49). Of the 143 patients, 23 had pre-intubation and post-intubation intracranial pressure values recorded; 11 received ketamine, and 3 of these patients had intracranial hypertension that resolved or improved, whereas the remaining 8 children had intracranial pressure within the normal range that was not exacerbated by ketamine. There were no significant differences in overall associated hemodynamic or respiratory events during tracheal intubation and no 24-h mortality in either group. CONCLUSIONS: The administration of ketamine as the primary induction agent prior to tracheal intubation in combination with other agents after tracheal intubation in children at risk for intracranial hypertension was not associated with an increased risk of peri-intubation associated neurologic, hemodynamic or respiratory events compared with those who received other induction agents.

Dural Venous Sinus Stenting in Idiopathic Intracranial Hypertension: A National Database Study of 541 Patients.

BACKGROUND: Dural venous sinus stenting (VSS) is an effective intervention for patients with idiopathic intracranial hypertension (IIH) refractory to medical treatment. Our goal was to evaluate the efficacy by utilizing a large multi-institutional sample. METHODS: Five hundred forty-one patients >18 years old who underwent VSS within 3 years of IIH diagnosis were queried using Current Procedural Terminology and International Classification of Diseases, Tenth Revision codes from the TriNetX Analytics Network. Patient demographics, baseline symptoms, procedures, and clinical outcomes were evaluated within 1 year postoperatively. Outcomes examined were headache, tinnitus, blindness/low vision, optic nerve sheath fenestration (ONSF), cerebrospinal fluid (CSF) shunt, and use of medications (acetazolamide, methazolamide, furosemide, topiramate, tricyclic antidepressants, and valproate) for IIH. Prestent and poststent data were compared using Fisher exact test, and the odds ratios were computed using the Baptista-Pike method. RESULTS: The mean age at VSS was 36.7 ± 10.6; 92% were female, 65% of patients were Caucasian, 25% were Black/African American, 1% were Asian, and 9% were of other/unknown race. Within the 1-year follow-up, acetazolamide and topiramate use were significantly reduced post-VSS (P < 0.0001∗; odds ratio, 0.45; confidence interval, 0.35-0.57 and P = 0.03∗; odds ratio, 0.71; confidence interval, 0.52-0.95, respectively). Also, headaches, visual disturbance, dizziness/giddiness, and tinnitus significantly improved post-VSS (P < 0.005∗). Finally, the number of CSF shunt procedures and ONSF procedures demonstrated no significant change post-VSS (P > 0.05). CONCLUSIONS: VSS is an effective and safe procedure resulting in significant improvement of headaches, visual impairment, dizziness, and tinnitus, acetazolamide and topiramate usage were lower after VSS in patients with IIH. The paucity of pre-VSS and post-VSS CSF shunt and ONSF procedure data does not provide enough evidence to establish significance.

Salted or sweet? Hypertonic saline or mannitol for treatment of intracranial hypertension.

PURPOSE OF REVIEW: The aim of this review article is to present current recommendations regarding the use of hypertonic saline and mannitol for the treatment of intracranial hypertension. RECENT FINDINGS: In recent years, a significant number of studies have been published comparing hypertonic saline with mannitol in patients with acute increased intracranial pressure, mostly caused by traumatic brain injury. Albeit several randomized controlled trials, systematic reviews and meta-analysis support hypertonic saline as more effective than mannitol in reducing intracranial pressure, no clear benefit in regards to the long-term neurologic outcome of these patients has been reported. SUMMARY: Identifying and treating increased intracranial pressure is imperative in neurocritical care settings and proper management is essential to improve long-term outcomes. Currently, there is insufficient evidence from comparative studies to support a formal recommendation on the use of any specific hyperosmolar medication in patients with acute increased intracranial pressure.

Acetazolamide modulates intracranial pressure directly by its action on the cerebrospinal fluid secretion apparatus.

BACKGROUND: Elevated intracranial pressure (ICP) is observed in many neurological pathologies, e.g. hydrocephalus and stroke. This condition is routinely relieved with neurosurgical approaches, since effective and targeted pharmacological tools are still lacking. The carbonic anhydrase inhibitor, acetazolamide (AZE), may be employed to treat elevated ICP. However, its effectiveness is questioned, its location of action unresolved, and its tolerability low. Here, we determined the efficacy and mode of action of AZE in the rat . METHODS: We employed in vivo approaches including ICP and cerebrospinal fluid secretion measurements in anaesthetized rats and telemetric monitoring of ICP and blood pressure in awake rats in combination with ex vivo choroidal radioisotope flux assays and transcriptomic analysis. RESULTS: AZE effectively reduced the ICP, irrespective of the mode of drug administration and level of anaesthesia. The effect appeared to occur via a direct action on the choroid plexus and an associated decrease in cerebrospinal fluid secretion, and not indirectly via the systemic action of AZE on renal and vascular processes. Upon a single administration, the reduced ICP endured for approximately 10 h post-AZE delivery with no long-term changes of brain water content or choroidal transporter expression. However, a persistent reduction of ICP was secured with repeated AZE administrations throughout the day. CONCLUSIONS: AZE lowers ICP directly via its ability to reduce the choroid plexus CSF secretion, irrespective of mode of drug administration.